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Medical devices and US 220V electrics

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  Medical devices and US 220V electrics RBlack <news@rblack01.plus.com> - 2017-05-25 13:05 +0100
    Re: Medical devices and US 220V electrics Winfield Hill <hill@rowland.harvard.edu> - 2017-05-25 05:55 -0700
    Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-05-25 17:26 +0300
      Re: Medical devices and US 220V electrics Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-05-25 10:27 -0400
        Re: Medical devices and US 220V electrics George Herold <gherold@teachspin.com> - 2017-05-25 08:39 -0700
          Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-25 12:40 -0400
      Re: Medical devices and US 220V electrics Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-25 15:03 +0000
        Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-05-25 20:09 +0300
      Re: Medical devices and US 220V electrics RBlack <news@rblack01.plus.com> - 2017-05-25 16:56 +0100
        Re: Medical devices and US 220V electrics Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-25 16:42 +0000
        Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-05-25 20:38 +0300
        Re: Medical devices and US 220V electrics whit3rd <whit3rd@gmail.com> - 2017-05-25 10:48 -0700
        Re: Medical devices and US 220V electrics Neon John <no@never.com> - 2017-05-28 15:48 -0400
        Re: Medical devices and US 220V electrics rickman <gnuarm@gmail.com> - 2017-05-29 01:08 -0400
      Re: Medical devices and US 220V electrics Cursitor Doom <curd@notformail.com> - 2017-05-25 17:51 +0000
        Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-05-25 21:25 +0300
      Re: Medical devices and US 220V electrics "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> - 2017-05-26 11:55 -0400
        Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-26 17:38 -0400
          Re: Medical devices and US 220V electrics "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> - 2017-05-26 20:32 -0400
            Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-26 22:20 -0400
              Re: Medical devices and US 220V electrics "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> - 2017-05-27 00:33 -0400
                Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-27 09:37 -0400
    Re: Medical devices and US 220V electrics legg <legg@nospam.magma.ca> - 2017-05-25 12:07 -0400
      Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-25 12:49 -0400
        Re: Medical devices and US 220V electrics Neon John <no@never.com> - 2017-05-28 15:56 -0400
          Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-28 16:59 -0400
        Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-05-30 12:37 +0300
          Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-30 17:41 -0400
      Re: Medical devices and US 220V electrics gregz <zekor@comcast.net> - 2017-05-30 06:58 +0000
    Re: Medical devices and US 220V electrics rickman <gnuarm@gmail.com> - 2017-05-25 12:15 -0400
      Re: Medical devices and US 220V electrics Jon Elson <jmelson@wustl.edu> - 2017-05-25 15:07 -0500
        Re: Medical devices and US 220V electrics John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-25 13:14 -0700
          Re: Medical devices and US 220V electrics Jon Elson <jmelson@wustl.edu> - 2017-05-25 16:34 -0500
        Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-25 18:47 -0400
          Re: Medical devices and US 220V electrics Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2017-05-27 01:46 +0200
            Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-26 19:53 -0400
              Re: Medical devices and US 220V electrics Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2017-05-27 02:05 +0200
                Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-26 22:21 -0400
                  Re: Medical devices and US 220V electrics Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2017-05-27 04:25 +0200
                    Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-26 22:33 -0400
                      Re: Medical devices and US 220V electrics Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2017-05-27 21:48 +0200
    Re: Medical devices and US 220V electrics Don Y <blockedofcourse@foo.invalid> - 2017-05-25 11:20 -0700
    Re: Medical devices and US 220V electrics Jon Elson <jmelson@wustl.edu> - 2017-05-25 14:57 -0500
      Re: Medical devices and US 220V electrics RBlack <news@rblack01.plus.com> - 2017-05-26 12:17 +0100
        Re: Medical devices and US 220V electrics tabbypurr@gmail.com - 2017-05-26 04:53 -0700
        Re: Medical devices and US 220V electrics Phil Allison <pallison49@gmail.com> - 2017-05-26 06:00 -0700
        Re: Medical devices and US 220V electrics rickman <gnuarm@gmail.com> - 2017-05-26 12:05 -0400
        Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-26 17:51 -0400
          Re: Medical devices and US 220V electrics George Herold <gherold@teachspin.com> - 2017-05-26 17:54 -0700
            Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-26 22:24 -0400
        Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-05-27 00:52 +0300
          Re: Medical devices and US 220V electrics Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-05-26 15:39 -0700
        Re: Medical devices and US 220V electrics Neon John <no@never.com> - 2017-05-28 16:34 -0400
          Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-28 17:26 -0400
            Re: Medical devices and US 220V electrics Neon John <no@never.com> - 2017-05-29 12:12 -0400
              Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-29 14:26 -0400
    Re: Medical devices and US 220V electrics Tim Wescott <tim@seemywebsite.really> - 2017-05-29 00:08 -0500
    Re: Medical devices and US 220V electrics David Lesher <wb8foz@panix.com> - 2017-05-29 20:24 +0000
      Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-29 16:37 -0400
        Re: Medical devices and US 220V electrics David Lesher <wb8foz@panix.com> - 2017-05-30 16:33 +0000
          Re: Medical devices and US 220V electrics Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-30 09:46 -0700
          Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-30 17:45 -0400
            Re: Medical devices and US 220V electrics David Lesher <wb8foz@panix.com> - 2017-05-31 03:31 +0000
              Re: Medical devices and US 220V electrics krw@notreal.com - 2017-05-31 17:58 -0400
                Re: Medical devices and US 220V electrics Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-01 07:54 +0000
                  Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-06-01 12:49 +0300
                    Re: Medical devices and US 220V electrics Neon John <no@never.com> - 2017-06-01 10:28 -0400
                      Re: Medical devices and US 220V electrics Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-01 14:45 +0000
                      Re: Medical devices and US 220V electrics Neon John <no@never.com> - 2017-06-01 18:47 -0400
                        Re: Medical devices and US 220V electrics Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-06-01 15:57 -0700
                          Re: Medical devices and US 220V electrics Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-06-02 07:21 +0000
                        Re: Medical devices and US 220V electrics krw@notreal.com - 2017-06-01 18:59 -0400
                Re: Medical devices and US 220V electrics David Lesher <wb8foz@panix.com> - 2017-06-03 14:00 +0000
                  Re: Medical devices and US 220V electrics krw@notreal.com - 2017-06-03 11:19 -0400
      Re: Medical devices and US 220V electrics upsidedown@downunder.com - 2017-05-30 01:16 +0300
        Re: Medical devices and US 220V electrics tabbypurr@gmail.com - 2017-05-29 22:31 -0700
          Re: Medical devices and US 220V electrics Phil Allison <pallison49@gmail.com> - 2017-05-29 23:06 -0700
            Re: Medical devices and US 220V electrics tabbypurr@gmail.com - 2017-05-29 23:25 -0700
              Re: Medical devices and US 220V electrics Phil Allison <pallison49@gmail.com> - 2017-05-29 23:39 -0700
                Re: Medical devices and US 220V electrics tabbypurr@gmail.com - 2017-05-30 00:19 -0700
              Re: Medical devices and US 220V electrics rickman <gnuarm@gmail.com> - 2017-05-30 10:40 -0400
      Re: Medical devices and US 220V electrics rickman <gnuarm@gmail.com> - 2017-05-30 10:37 -0400
    Re: Medical devices and US 220V electrics Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-30 16:58 -0700
      Re: Medical devices and US 220V electrics Don Y <blockedofcourse@foo.invalid> - 2017-05-30 22:15 -0700
        Re: Medical devices and US 220V electrics Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-31 07:38 -0700
      Re: Medical devices and US 220V electrics Don Kuenz <g@crcomp.net> - 2017-05-31 14:05 +0000
        Re: Medical devices and US 220V electrics Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-31 07:40 -0700
        Re: Medical devices and US 220V electrics Don Y <blockedofcourse@foo.invalid> - 2017-05-31 09:37 -0700

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#462013

On 27.05.17 4:33, krw@notreal.com wrote:
> On Sat, 27 May 2017 04:25:17 +0200, Sjouke Burry
> <burrynulnulfour@ppllaanneett.nnll> wrote:
>
>> On 27.05.17 4:21, krw@notreal.com wrote:
>>> On Sat, 27 May 2017 02:05:24 +0200, Sjouke Burry
>>> <burrynulnulfour@ppllaanneett.nnll> wrote:
>>>
>>>> On 27.05.17 1:53, krw@notreal.com wrote:
>>>>> On Sat, 27 May 2017 01:46:41 +0200, Sjouke Burry
>>>>> <burrynulnulfour@ppllaanneett.nnll> wrote:
>>>>>
>>>>>> On 26.05.17 0:47, krw@notreal.com wrote:
>>>>>>> On Thu, 25 May 2017 15:07:13 -0500, Jon Elson <jmelson@wustl.edu>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> rickman wrote:
>>>>>>>>
>>>>>>>>> No, 220 VAC is not common in the US, at least not in homes or offices.
>>>>>>>>> I don't know what hospitals might have.
>>>>>>>>
>>>>>>>> Actually, 120/208 Wye service is quite common in larger offices.  Might not
>>>>>>>> have it in the typical storefront-type building, but almost any multi-level
>>>>>>>> office building will likely have that system.  It gives lots of 120 V
>>>>>>>> single-phase outlets, and 208 V between any two hots.  Smaller air
>>>>>>>> conditioners would have 3-phase compressors off the 208 mains.  The building
>>>>>>>> I work in has 120/208 Wye in the offices, 120/208 Wye PLUS 230 Delta in the
>>>>>>>> lab space and 480 in the mechanical areas.
>>>>>>>>
>>>>>>>> 3 Phase is VERY rare in single-family homes, but common in apartment
>>>>>>>> buildings.  And, certainly, any hospital will have 3-phase panels throughout
>>>>>>>> the building.
>>>>>>>
>>>>>>> 3-Phase will certainly be common in large apartment buildings but
>>>>>>> it'll never be found inside a single apartment.  Think of the building
>>>>>>> as a neighborhood.  ;-)
>>>>>>>
>>>>>> Hmm... I have a 220/380 3 phase cable feeding into my house, although I
>>>>>> use only one of them.(In the dim past each house got current from
>>>>>> 1 of those 3 wires)
>>>>>
>>>>> My house?  Each house?  Please explain.
>>>>>
>>>> 3 houses, mine is the middle one, and each phase feeding 1 house.
>>>> That way, I end up with  a 3phase power cable.
>>>
>>> Why does the cable for the other two houses enter yours?  Row houses?
>>>
>> A row of 3. And why only one feed cable? I have no idea.
>
> OK, makes sense.  I can see why they feed only one.  The meters for
> all three units are on your wall, too, I suppose?
>
No. Just two armoured cables going to the neighbours through
the ceiling.

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#461701

On 5/25/2017 5:05 AM, RBlack wrote:
> Hi,
>
> We are working on a medical product, which will draw about 3 kW from the
> mains.  This is new territory for us, all our previous products were a
> few hundred watts max so an off-the-shelf auto-ranging PSU with a
> suitable IEC lead was OK for any country in the world.
>
> 3 kW is OK for a standard outlet in 220V countries, but for North
> America, Japan etc we are over the limit for a standard 110V outlet.

Note that US branch circuits are typically derated to 80%.  So, a 15A
branch circuit would nominally be loaded at 1440W; 20A at 1920W; etc.

> I only know as much about US electrical installations as I've read, a
> bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
> But how common are these in hospitals?  Anybody have any experience of
> this stuff?

I have a server with a NEMA 6-15 plug; another with a 6-20.  But, these
aren't typically encountered in residences.  OTOH, the stovetop uses
a 10-50 (or 10-30?), IIRC (there is a legacy issue, there).  Several
5-20's (garage, kitchen, furnace, yard, etc.)

> It has been suggested (not by me I hasten to add) that we split the
> loads within the product up and give it two 110V inlets, to get around
> the customer having to install a 'special' outlet for it.  This sounds
> like a Really Bad Idea and a regulatory nightmare to me, so if 220V
> outlets are commonly available anyway I can shoot it down before it gets
> too far.

No.  Design the product as you (i.e., others) would *expect* it to be
designed.  Hospitals *design* rooms to accommodate the bits of kit
that they will house (I am assuming your device is NOT something that
would be wheeled around -- portable -- to individual rooms, as needed).
E.g., you don't think the MRI runs off a standard 115V/20A outlet!

Note that you should also consider the repurcussions for your (unnamed)
bit of kit in the event of a power outage; big loads are hard to
"backup" -- would the facility want/need to keep your device operational
in the event of an outage?  (or, could its use be deferred?)

[toc] | [prev] | [next] | [standalone]

#461717

RBlack wrote:

> Hi,
> 
> We are working on a medical product, which will draw about 3 kW from the
> mains.  This is new territory for us, all our previous products were a
> few hundred watts max so an off-the-shelf auto-ranging PSU with a
> suitable IEC lead was OK for any country in the world.
> 
> 3 kW is OK for a standard outlet in 220V countries, but for North
> America, Japan etc we are over the limit for a standard 110V outlet.
> 
> I only know as much about US electrical installations as I've read, a
> bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
> But how common are these in hospitals?  Anybody have any experience of
> this stuff?
> 
> It has been suggested (not by me I hasten to add) that we split the
> loads within the product up and give it two 110V inlets, to get around
> the customer having to install a 'special' outlet for it.  This sounds
> like a Really Bad Idea and a regulatory nightmare to me, so if 220V
> outlets are commonly available anyway I can shoot it down before it gets
> too far.
Yup, multiple power sources require jumping through a bunch more regulatory 
hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
although most of those are battery-powered.  I guess there's other gear that 
also needs a 220 V outlet.  If the units are for soemthing else than patient 
rooms, I doubt there'd be any problem.

Jon

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#461788

On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
> RBlack wrote:
> 
> > Hi,
> > 
> > We are working on a medical product, which will draw about 3 kW from the
> > mains.  This is new territory for us, all our previous products were a
> > few hundred watts max so an off-the-shelf auto-ranging PSU with a
> > suitable IEC lead was OK for any country in the world.
> > 
> > 3 kW is OK for a standard outlet in 220V countries, but for North
> > America, Japan etc we are over the limit for a standard 110V outlet.
> > 
> > I only know as much about US electrical installations as I've read, a
> > bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
> > But how common are these in hospitals?  Anybody have any experience of
> > this stuff?
> > 
> > It has been suggested (not by me I hasten to add) that we split the
> > loads within the product up and give it two 110V inlets, to get around
> > the customer having to install a 'special' outlet for it.  This sounds
> > like a Really Bad Idea and a regulatory nightmare to me, so if 220V
> > outlets are commonly available anyway I can shoot it down before it gets
> > too far.
> Yup, multiple power sources require jumping through a bunch more regulatory 
> hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
> although most of those are battery-powered.  I guess there's other gear that 
> also needs a 220 V outlet.  If the units are for soemthing else than patient 
> rooms, I doubt there'd be any problem.
> 
> Jon
> 
Thanks for all the replies so far.  Still early in the development, I 
don't have all the requirements yet.

The product gets wheeled into the operating room and used for part of 
the procedure, then wheeled out into another room to be prepared for the 
next operation.  It needs power in both locations.
It doesn't have any patient applied parts, but as it's used in the 
vicinity of the patient it does fall under 60601 and related standards.

I knew about the dedicated 220V outlets in residential buildings for 
clothes driers, air conditioners etc, from previous discussions on here.  
I wouldn't expect to find these in a hospital building, hence my 
question about the 6-15 type.  

So, in summary:

- 220V supply is available in all buildings, but we can't expect to find 
a 220V outlet unused and available for use with our product on a given 
customer's premises, they typically have to be installed in each 
location as needed.

- A dedicated install is preferred anyway, to make sure the wiring, 
breakers, etc are rated adequately for the product.  Just because a type 
of outlet is rated for X amps, doesn't mean the wiring and breakers 
behind it are.

- Standard 110V outlets are everywhere, but we can't expect to be able 
to draw more than 10A continuously from one of these.

Somebody please correct me if I've misunderstood anything.

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#461790

On Friday, 26 May 2017 12:17:15 UTC+1, RBlack  wrote:
> On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
> > RBlack wrote:
> > 
> > > Hi,
> > > 
> > > We are working on a medical product, which will draw about 3 kW from the
> > > mains.  This is new territory for us, all our previous products were a
> > > few hundred watts max so an off-the-shelf auto-ranging PSU with a
> > > suitable IEC lead was OK for any country in the world.
> > > 
> > > 3 kW is OK for a standard outlet in 220V countries, but for North
> > > America, Japan etc we are over the limit for a standard 110V outlet.
> > > 
> > > I only know as much about US electrical installations as I've read, a
> > > bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
> > > But how common are these in hospitals?  Anybody have any experience of
> > > this stuff?
> > > 
> > > It has been suggested (not by me I hasten to add) that we split the
> > > loads within the product up and give it two 110V inlets, to get around
> > > the customer having to install a 'special' outlet for it.  This sounds
> > > like a Really Bad Idea and a regulatory nightmare to me, so if 220V
> > > outlets are commonly available anyway I can shoot it down before it gets
> > > too far.
> > Yup, multiple power sources require jumping through a bunch more regulatory 
> > hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
> > although most of those are battery-powered.  I guess there's other gear that 
> > also needs a 220 V outlet.  If the units are for soemthing else than patient 
> > rooms, I doubt there'd be any problem.
> > 
> > Jon
> > 
> Thanks for all the replies so far.  Still early in the development, I 
> don't have all the requirements yet.
> 
> The product gets wheeled into the operating room and used for part of 
> the procedure, then wheeled out into another room to be prepared for the 
> next operation.  It needs power in both locations.
> It doesn't have any patient applied parts, but as it's used in the 
> vicinity of the patient it does fall under 60601 and related standards.
> 
> I knew about the dedicated 220V outlets in residential buildings for 
> clothes driers, air conditioners etc, from previous discussions on here.  
> I wouldn't expect to find these in a hospital building, hence my 
> question about the 6-15 type.  
> 
> So, in summary:
> 
> - 220V supply is available in all buildings, but we can't expect to find 
> a 220V outlet unused and available for use with our product on a given 
> customer's premises, they typically have to be installed in each 
> location as needed.
> 
> - A dedicated install is preferred anyway, to make sure the wiring, 
> breakers, etc are rated adequately for the product.  Just because a type 
> of outlet is rated for X amps, doesn't mean the wiring and breakers 
> behind it are.
> 
> - Standard 110V outlets are everywhere, but we can't expect to be able 
> to draw more than 10A continuously from one of these.
> 
> Somebody please correct me if I've misunderstood anything.

Surely your primary question is one where you really need to know. No maybes. Asking people that aren't in this field won't get you that.


NT

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#461796

 RBlack wrote:

---------------
>

> 
> So, in summary:
> 
> - 220V supply is available in all buildings, but we can't expect to find 
> a 220V outlet unused and available for use with our product on a given 
> customer's premises, they typically have to be installed in each 
> location as needed.
> 
> - A dedicated install is preferred anyway, to make sure the wiring, 
> breakers, etc are rated adequately for the product.  Just because a type 
> of outlet is rated for X amps, doesn't mean the wiring and breakers 
> behind it are.
> 
> - Standard 110V outlets are everywhere, but we can't expect to be able 
> to draw more than 10A continuously from one of these.
> 
> Somebody please correct me if I've misunderstood anything.
>


** Standard US outlets are rated at 120V and 15 amps. 

   1800 VA.  



....  Phil 

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#461820

RBlack wrote on 5/26/2017 7:17 AM:
> On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
>> RBlack wrote:
>>
>>> Hi,
>>>
>>> We are working on a medical product, which will draw about 3 kW from the
>>> mains.  This is new territory for us, all our previous products were a
>>> few hundred watts max so an off-the-shelf auto-ranging PSU with a
>>> suitable IEC lead was OK for any country in the world.
>>>
>>> 3 kW is OK for a standard outlet in 220V countries, but for North
>>> America, Japan etc we are over the limit for a standard 110V outlet.
>>>
>>> I only know as much about US electrical installations as I've read, a
>>> bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
>>> But how common are these in hospitals?  Anybody have any experience of
>>> this stuff?
>>>
>>> It has been suggested (not by me I hasten to add) that we split the
>>> loads within the product up and give it two 110V inlets, to get around
>>> the customer having to install a 'special' outlet for it.  This sounds
>>> like a Really Bad Idea and a regulatory nightmare to me, so if 220V
>>> outlets are commonly available anyway I can shoot it down before it gets
>>> too far.
>> Yup, multiple power sources require jumping through a bunch more regulatory
>> hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray,
>> although most of those are battery-powered.  I guess there's other gear that
>> also needs a 220 V outlet.  If the units are for soemthing else than patient
>> rooms, I doubt there'd be any problem.
>>
>> Jon
>>
> Thanks for all the replies so far.  Still early in the development, I
> don't have all the requirements yet.
>
> The product gets wheeled into the operating room and used for part of
> the procedure, then wheeled out into another room to be prepared for the
> next operation.  It needs power in both locations.
> It doesn't have any patient applied parts, but as it's used in the
> vicinity of the patient it does fall under 60601 and related standards.
>
> I knew about the dedicated 220V outlets in residential buildings for
> clothes driers, air conditioners etc, from previous discussions on here.
> I wouldn't expect to find these in a hospital building, hence my
> question about the 6-15 type.
>
> So, in summary:
>
> - 220V supply is available in all buildings, but we can't expect to find
> a 220V outlet unused and available for use with our product on a given
> customer's premises, they typically have to be installed in each
> location as needed.
>
> - A dedicated install is preferred anyway, to make sure the wiring,
> breakers, etc are rated adequately for the product.  Just because a type
> of outlet is rated for X amps, doesn't mean the wiring and breakers
> behind it are.

Actually it does.  As someone pointed out the "rated" current would need 
to be derated appropriately, but the *entire* circuit will be capable of 
supplying that current.

> - Standard 110V outlets are everywhere, but we can't expect to be able
> to draw more than 10A continuously from one of these.
>
> Somebody please correct me if I've misunderstood anything.

If this is going to be used in a hospital OR and adjacent rooms, I think 
it won't be a problem getting you the power you need.  That is totally 
different from a hospital room or in a home.

One caveat, I requested a new outlet in an office building once, for an 
early laser printer (B sized).  We were told to ask for a dedicated 
circuit and did.  But out computers in the same room kept crashing.  We 
eventually found the printer was putting a lot of garbage on the line. 
Turns out "dedicated" wasn't an adequate specification to get a line all 
the way back to the circuit panel.  I expect the contractor was blowing 
smoke, but we had to use some different words for that, which I don't 
quite recall.  In US hospitals these truly dedicated circuits have an 
orange outlet.

-- 

Rick C

[toc] | [prev] | [next] | [standalone]

#461883

On Fri, 26 May 2017 12:17:12 +0100, RBlack <news@rblack01.plus.com>
wrote:

>On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
>> RBlack wrote:
>> 
>> > Hi,
>> > 
>> > We are working on a medical product, which will draw about 3 kW from the
>> > mains.  This is new territory for us, all our previous products were a
>> > few hundred watts max so an off-the-shelf auto-ranging PSU with a
>> > suitable IEC lead was OK for any country in the world.
>> > 
>> > 3 kW is OK for a standard outlet in 220V countries, but for North
>> > America, Japan etc we are over the limit for a standard 110V outlet.
>> > 
>> > I only know as much about US electrical installations as I've read, a
>> > bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
>> > But how common are these in hospitals?  Anybody have any experience of
>> > this stuff?
>> > 
>> > It has been suggested (not by me I hasten to add) that we split the
>> > loads within the product up and give it two 110V inlets, to get around
>> > the customer having to install a 'special' outlet for it.  This sounds
>> > like a Really Bad Idea and a regulatory nightmare to me, so if 220V
>> > outlets are commonly available anyway I can shoot it down before it gets
>> > too far.
>> Yup, multiple power sources require jumping through a bunch more regulatory 
>> hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
>> although most of those are battery-powered.  I guess there's other gear that 
>> also needs a 220 V outlet.  If the units are for soemthing else than patient 
>> rooms, I doubt there'd be any problem.
>> 
>> Jon
>> 
>Thanks for all the replies so far.  Still early in the development, I 
>don't have all the requirements yet.
>
>The product gets wheeled into the operating room and used for part of 
>the procedure, then wheeled out into another room to be prepared for the 
>next operation.  It needs power in both locations.
>It doesn't have any patient applied parts, but as it's used in the 
>vicinity of the patient it does fall under 60601 and related standards.
>
>I knew about the dedicated 220V outlets in residential buildings for 
>clothes driers, air conditioners etc, from previous discussions on here.  
>I wouldn't expect to find these in a hospital building, hence my 
>question about the 6-15 type.  
>
>So, in summary:
>
>- 220V supply is available in all buildings, but we can't expect to find 
>a 220V outlet unused and available for use with our product on a given 
>customer's premises, they typically have to be installed in each 
>location as needed.

As long as there is 120V in the building, 240V isn't a problem.
>
>- A dedicated install is preferred anyway, to make sure the wiring, 
>breakers, etc are rated adequately for the product.  

Not necessarily.  If I read your posts correctly, your device is not
permanently installed, so you really don't want a dedicated install.  

>Just because a type 
>of outlet is rated for X amps, doesn't mean the wiring and breakers 
>behind it are.

Yes, it does.  Of course the installing electrician could be a moron
but it is against code to put an outlet on a circuit that is larger
than the circuit will support.  Likewise fuses/wiring (wiring can be
smaller but not larger than the OC device).

>- Standard 110V outlets are everywhere, but we can't expect to be able 
>to draw more than 10A continuously from one of these.

15A (max) is perfectly acceptable from a NEMA 5-15 outlet on a 20A
circuit (by far the most common combination), particularly if it's not
a "permanent" installation.  Just remember that there may be other
stuff on the circuit (but this could be a problem even at 10A).

>Somebody please correct me if I've misunderstood anything.

I think a survey of your anticipated customer base is in order.  

[toc] | [prev] | [next] | [standalone]

#461928

On Friday, May 26, 2017 at 5:51:40 PM UTC-4, k...@notreal.com wrote:
> On Fri, 26 May 2017 12:17:12 +0100, RBlack <news@rblack01.plus.com>
> wrote:
> 
> >On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
> >> RBlack wrote:
> >> 
> >> > Hi,
> >> > 
> >> > We are working on a medical product, which will draw about 3 kW from the
> >> > mains.  This is new territory for us, all our previous products were a
> >> > few hundred watts max so an off-the-shelf auto-ranging PSU with a
> >> > suitable IEC lead was OK for any country in the world.
> >> > 
> >> > 3 kW is OK for a standard outlet in 220V countries, but for North
> >> > America, Japan etc we are over the limit for a standard 110V outlet.
> >> > 
> >> > I only know as much about US electrical installations as I've read, a
> >> > bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
> >> > But how common are these in hospitals?  Anybody have any experience of
> >> > this stuff?
> >> > 
> >> > It has been suggested (not by me I hasten to add) that we split the
> >> > loads within the product up and give it two 110V inlets, to get around
> >> > the customer having to install a 'special' outlet for it.  This sounds
> >> > like a Really Bad Idea and a regulatory nightmare to me, so if 220V
> >> > outlets are commonly available anyway I can shoot it down before it gets
> >> > too far.
> >> Yup, multiple power sources require jumping through a bunch more regulatory 
> >> hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
> >> although most of those are battery-powered.  I guess there's other gear that 
> >> also needs a 220 V outlet.  If the units are for soemthing else than patient 
> >> rooms, I doubt there'd be any problem.
> >> 
> >> Jon
> >> 
> >Thanks for all the replies so far.  Still early in the development, I 
> >don't have all the requirements yet.
> >
> >The product gets wheeled into the operating room and used for part of 
> >the procedure, then wheeled out into another room to be prepared for the 
> >next operation.  It needs power in both locations.
> >It doesn't have any patient applied parts, but as it's used in the 
> >vicinity of the patient it does fall under 60601 and related standards.
> >
> >I knew about the dedicated 220V outlets in residential buildings for 
> >clothes driers, air conditioners etc, from previous discussions on here.  
> >I wouldn't expect to find these in a hospital building, hence my 
> >question about the 6-15 type.  
> >
> >So, in summary:
> >
> >- 220V supply is available in all buildings, but we can't expect to find 
> >a 220V outlet unused and available for use with our product on a given 
> >customer's premises, they typically have to be installed in each 
> >location as needed.
> 
> As long as there is 120V in the building, 240V isn't a problem.
I have no idea, but I would guess most US hospitals have 240Vac 
outlets.  The OP mostly needs to find out what plug is 'standard'.

George H. 
> >
> >- A dedicated install is preferred anyway, to make sure the wiring, 
> >breakers, etc are rated adequately for the product.  
> 
> Not necessarily.  If I read your posts correctly, your device is not
> permanently installed, so you really don't want a dedicated install.  
> 
> >Just because a type 
> >of outlet is rated for X amps, doesn't mean the wiring and breakers 
> >behind it are.
> 
> Yes, it does.  Of course the installing electrician could be a moron
> but it is against code to put an outlet on a circuit that is larger
> than the circuit will support.  Likewise fuses/wiring (wiring can be
> smaller but not larger than the OC device).
> 
> >- Standard 110V outlets are everywhere, but we can't expect to be able 
> >to draw more than 10A continuously from one of these.
> 
> 15A (max) is perfectly acceptable from a NEMA 5-15 outlet on a 20A
> circuit (by far the most common combination), particularly if it's not
> a "permanent" installation.  Just remember that there may be other
> stuff on the circuit (but this could be a problem even at 10A).
> 
> >Somebody please correct me if I've misunderstood anything.
> 
> I think a survey of your anticipated customer base is in order.

[toc] | [prev] | [next] | [standalone]

#461943

On Fri, 26 May 2017 17:54:38 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

>On Friday, May 26, 2017 at 5:51:40 PM UTC-4, k...@notreal.com wrote:
>> On Fri, 26 May 2017 12:17:12 +0100, RBlack <news@rblack01.plus.com>
>> wrote:
>> 
>> >On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
>> >> RBlack wrote:
>> >> 
>> >> > Hi,
>> >> > 
>> >> > We are working on a medical product, which will draw about 3 kW from the
>> >> > mains.  This is new territory for us, all our previous products were a
>> >> > few hundred watts max so an off-the-shelf auto-ranging PSU with a
>> >> > suitable IEC lead was OK for any country in the world.
>> >> > 
>> >> > 3 kW is OK for a standard outlet in 220V countries, but for North
>> >> > America, Japan etc we are over the limit for a standard 110V outlet.
>> >> > 
>> >> > I only know as much about US electrical installations as I've read, a
>> >> > bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
>> >> > But how common are these in hospitals?  Anybody have any experience of
>> >> > this stuff?
>> >> > 
>> >> > It has been suggested (not by me I hasten to add) that we split the
>> >> > loads within the product up and give it two 110V inlets, to get around
>> >> > the customer having to install a 'special' outlet for it.  This sounds
>> >> > like a Really Bad Idea and a regulatory nightmare to me, so if 220V
>> >> > outlets are commonly available anyway I can shoot it down before it gets
>> >> > too far.
>> >> Yup, multiple power sources require jumping through a bunch more regulatory 
>> >> hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
>> >> although most of those are battery-powered.  I guess there's other gear that 
>> >> also needs a 220 V outlet.  If the units are for soemthing else than patient 
>> >> rooms, I doubt there'd be any problem.
>> >> 
>> >> Jon
>> >> 
>> >Thanks for all the replies so far.  Still early in the development, I 
>> >don't have all the requirements yet.
>> >
>> >The product gets wheeled into the operating room and used for part of 
>> >the procedure, then wheeled out into another room to be prepared for the 
>> >next operation.  It needs power in both locations.
>> >It doesn't have any patient applied parts, but as it's used in the 
>> >vicinity of the patient it does fall under 60601 and related standards.
>> >
>> >I knew about the dedicated 220V outlets in residential buildings for 
>> >clothes driers, air conditioners etc, from previous discussions on here.  
>> >I wouldn't expect to find these in a hospital building, hence my 
>> >question about the 6-15 type.  
>> >
>> >So, in summary:
>> >
>> >- 220V supply is available in all buildings, but we can't expect to find 
>> >a 220V outlet unused and available for use with our product on a given 
>> >customer's premises, they typically have to be installed in each 
>> >location as needed.
>> 
>> As long as there is 120V in the building, 240V isn't a problem.
>I have no idea, but I would guess most US hospitals have 240Vac 
>outlets.  The OP mostly needs to find out what plug is 'standard'.

"Find out" are the operative words but changing a plug is a trivial
matter (one all the time on household ovens and clothes dryers).
Service availability isn't quite as simple.  

[toc] | [prev] | [next] | [standalone]

#461884

On Fri, 26 May 2017 12:17:12 +0100, RBlack <news@rblack01.plus.com>
wrote:

>On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
>> RBlack wrote:
>> 
>> > Hi,
>> > 
>> > We are working on a medical product, which will draw about 3 kW from the
>> > mains.  This is new territory for us, all our previous products were a
>> > few hundred watts max so an off-the-shelf auto-ranging PSU with a
>> > suitable IEC lead was OK for any country in the world.
>> > 
>> > 3 kW is OK for a standard outlet in 220V countries, but for North
>> > America, Japan etc we are over the limit for a standard 110V outlet.
>> > 
>> > I only know as much about US electrical installations as I've read, a
>> > bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
>> > But how common are these in hospitals?  Anybody have any experience of
>> > this stuff?
>> > 
>> > It has been suggested (not by me I hasten to add) that we split the
>> > loads within the product up and give it two 110V inlets, to get around
>> > the customer having to install a 'special' outlet for it.  This sounds
>> > like a Really Bad Idea and a regulatory nightmare to me, so if 220V
>> > outlets are commonly available anyway I can shoot it down before it gets
>> > too far.
>> Yup, multiple power sources require jumping through a bunch more regulatory 
>> hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
>> although most of those are battery-powered.  I guess there's other gear that 
>> also needs a 220 V outlet.  If the units are for soemthing else than patient 
>> rooms, I doubt there'd be any problem.
>> 
>> Jon
>> 
>Thanks for all the replies so far.  Still early in the development, I 
>don't have all the requirements yet.
>
>The product gets wheeled into the operating room and used for part of 
>the procedure, then wheeled out into another room to be prepared for the 
>next operation.  It needs power in both locations.
>It doesn't have any patient applied parts, but as it's used in the 
>vicinity of the patient it does fall under 60601 and related standards.
>
>I knew about the dedicated 220V outlets in residential buildings for 
>clothes driers, air conditioners etc, from previous discussions on here.  
>I wouldn't expect to find these in a hospital building, hence my 
>question about the 6-15 type.  
>
>So, in summary:
>
>- 220V supply is available in all buildings, but we can't expect to find 
>a 220V outlet unused and available for use with our product on a given 
>customer's premises, they typically have to be installed in each 
>location as needed.
>
>- A dedicated install is preferred anyway, to make sure the wiring, 
>breakers, etc are rated adequately for the product.  Just because a type 
>of outlet is rated for X amps, doesn't mean the wiring and breakers 
>behind it are.
>
>- Standard 110V outlets are everywhere, but we can't expect to be able 
>to draw more than 10A continuously from one of these.
>
>Somebody please correct me if I've misunderstood anything.
>
>

I am quoting this out of memory for more than 30 years ago, so this
might not ne too accurate:

At least some decades ago in Europe 3 phase isolation transformers
were used to isolate the normal 220/380 V wye/delta feed primary from
the 220/380 isolated secondary in an operating theater. 

The secondary star point was grounded via a 1 Mohm resistor
https://en.wikipedia.org/wiki/Earthing_system#IT_network

So if you had a ground fault, that phase would go to 0 V, while the
two other phases went to 400 V. The star point went to 230 V above
ground and an alarm could then be generated.

Even with a single phase ground fault, there was no problem continuing
the operation. After the operation was completed, the ground fault
could be repaired, before starting the next operation.

[toc] | [prev] | [next] | [standalone]

#461902

Den fredag den 26. maj 2017 kl. 23.52.11 UTC+2 skrev upsid...@downunder.com:
> On Fri, 26 May 2017 12:17:12 +0100, RBlack <news@rblack01.plus.com>
> wrote:
> 
> >On Thu, 25 May 2017 14:57:18 -0500, Jon Elson (jmelson@wustl.edu) said:
> >> RBlack wrote:
> >> 
> >> > Hi,
> >> > 
> >> > We are working on a medical product, which will draw about 3 kW from the
> >> > mains.  This is new territory for us, all our previous products were a
> >> > few hundred watts max so an off-the-shelf auto-ranging PSU with a
> >> > suitable IEC lead was OK for any country in the world.
> >> > 
> >> > 3 kW is OK for a standard outlet in 220V countries, but for North
> >> > America, Japan etc we are over the limit for a standard 110V outlet.
> >> > 
> >> > I only know as much about US electrical installations as I've read, a
> >> > bit of Googling suggests the product will need a NEMA 6-15 220V outlet.
> >> > But how common are these in hospitals?  Anybody have any experience of
> >> > this stuff?
> >> > 
> >> > It has been suggested (not by me I hasten to add) that we split the
> >> > loads within the product up and give it two 110V inlets, to get around
> >> > the customer having to install a 'special' outlet for it.  This sounds
> >> > like a Really Bad Idea and a regulatory nightmare to me, so if 220V
> >> > outlets are commonly available anyway I can shoot it down before it gets
> >> > too far.
> >> Yup, multiple power sources require jumping through a bunch more regulatory 
> >> hoops.  Hospital rooms generally have a 240 V outlet for portable X-ray, 
> >> although most of those are battery-powered.  I guess there's other gear that 
> >> also needs a 220 V outlet.  If the units are for soemthing else than patient 
> >> rooms, I doubt there'd be any problem.
> >> 
> >> Jon
> >> 
> >Thanks for all the replies so far.  Still early in the development, I 
> >don't have all the requirements yet.
> >
> >The product gets wheeled into the operating room and used for part of 
> >the procedure, then wheeled out into another room to be prepared for the 
> >next operation.  It needs power in both locations.
> >It doesn't have any patient applied parts, but as it's used in the 
> >vicinity of the patient it does fall under 60601 and related standards.
> >
> >I knew about the dedicated 220V outlets in residential buildings for 
> >clothes driers, air conditioners etc, from previous discussions on here.  
> >I wouldn't expect to find these in a hospital building, hence my 
> >question about the 6-15 type.  
> >
> >So, in summary:
> >
> >- 220V supply is available in all buildings, but we can't expect to find 
> >a 220V outlet unused and available for use with our product on a given 
> >customer's premises, they typically have to be installed in each 
> >location as needed.
> >
> >- A dedicated install is preferred anyway, to make sure the wiring, 
> >breakers, etc are rated adequately for the product.  Just because a type 
> >of outlet is rated for X amps, doesn't mean the wiring and breakers 
> >behind it are.
> >
> >- Standard 110V outlets are everywhere, but we can't expect to be able 
> >to draw more than 10A continuously from one of these.
> >
> >Somebody please correct me if I've misunderstood anything.
> >
> >
> 
> I am quoting this out of memory for more than 30 years ago, so this
> might not ne too accurate:
> 
> At least some decades ago in Europe 3 phase isolation transformers
> were used to isolate the normal 220/380 V wye/delta feed primary from
> the 220/380 isolated secondary in an operating theater. 
> 
> The secondary star point was grounded via a 1 Mohm resistor
> https://en.wikipedia.org/wiki/Earthing_system#IT_network
> 
> So if you had a ground fault, that phase would go to 0 V, while the
> two other phases went to 400 V. The star point went to 230 V above
> ground and an alarm could then be generated.
> 
> Even with a single phase ground fault, there was no problem continuing
> the operation. After the operation was completed, the ground fault
> could be repaired, before starting the next operation.

sound similar to how I understand it is often done on ships, an ohmmeter 
from the floating star point to the hull, if it goes below some megaohm
someone has to go find out where the leak is

[toc] | [prev] | [next] | [standalone]

#462113

On Fri, 26 May 2017 12:17:12 +0100, RBlack <news@rblack01.plus.com>
wrote:


>I knew about the dedicated 220V outlets in residential buildings for 
>clothes driers, air conditioners etc, from previous discussions on here.  
>I wouldn't expect to find these in a hospital building, hence my 
>question about the 6-15 type. 

Something you need to realize is that 110/220 power hasn't existed in
the US since the 60s.  The standard single phase power is 120/240 or
if you're unlucky enough to be operating in a straight 3 phase
building, the single phase voltage will be 120/208.  All of these are
+- 5%.

The voltage where I live is on the high side, 125/250.  I think that
is not uncommon in rural areas where long runs of primary cable
resistance must be overcome.
 
>- A dedicated install is preferred anyway, to make sure the wiring, 
>breakers, etc are rated adequately for the product.  Just because a type 
>of outlet is rated for X amps, doesn't mean the wiring and breakers 
>behind it are.

There is a section in the code that calls out 80% capacity but in
practice I find that not the case.  I can set the current draw and
thus the output power of our 120 volt induction heater to whatever I
want.  

Except for the cheapest of cheap spec houses, modern wiring uses 20
amp breakers and NEMA 5-20 outlets.  An expansion on the differences
between 15 and 20 amp branches is here:

http://www.paragonweb.com/Kiln_Pointer.cfm?PID=446

I have tested a whole bunch of 20 amp 120 volt panel box breakers and
find that they all sustain 20 amps indefinitely.  The manufacturer can
supply a data sheet.  The typical long delay or "motor starting"
breaker will hold 40 amps for the better part of a minute.

>
>- Standard 110V outlets are everywhere, but we can't expect to be able 
>to draw more than 10A continuously from one of these.

I set our induction heaters to draw up to 19 amps and equip it with a
5-20P cord set.  No complaints in over 6 years.

Wiki page on the various NEMA types:

https://en.wikipedia.org/wiki/NEMA_connector

I suggest doing what I did and that is to design your power factor
controller so that the maximum amps can be limited with an adjustment
pot.  That way if you run into a situation with nuisance trips or a
weak breaker on a commonly used branch, you can turn the amp draw down
just a bit.

John

John DeArmond
http://www.neon-john.com
http://www.tnduction.com 
Tellico Plains, Occupied TN
See website for email address

[toc] | [prev] | [next] | [standalone]

#462123

On Sun, 28 May 2017 16:34:58 -0400, Neon John <no@never.com> wrote:

>On Fri, 26 May 2017 12:17:12 +0100, RBlack <news@rblack01.plus.com>
>wrote:
>
>
>>I knew about the dedicated 220V outlets in residential buildings for 
>>clothes driers, air conditioners etc, from previous discussions on here.  
>>I wouldn't expect to find these in a hospital building, hence my 
>>question about the 6-15 type. 
>
>Something you need to realize is that 110/220 power hasn't existed in
>the US since the 60s.  The standard single phase power is 120/240 or
>if you're unlucky enough to be operating in a straight 3 phase
>building, the single phase voltage will be 120/208.  All of these are
>+- 5%.
>
>The voltage where I live is on the high side, 125/250.  I think that
>is not uncommon in rural areas where long runs of primary cable
>resistance must be overcome.
> 
>>- A dedicated install is preferred anyway, to make sure the wiring, 
>>breakers, etc are rated adequately for the product.  Just because a type 
>>of outlet is rated for X amps, doesn't mean the wiring and breakers 
>>behind it are.
>
>There is a section in the code that calls out 80% capacity but in
>practice I find that not the case.  I can set the current draw and
>thus the output power of our 120 volt induction heater to whatever I
>want.  

AIUI, the 80% capacity rule is for dedicated circuits.  Any such spec
for utility circuits would be meaningless.   Likewise, it also doesn't
apply to devices plugged into the utility circuits.

>Except for the cheapest of cheap spec houses, modern wiring uses 20
>amp breakers and NEMA 5-20 outlets.  An expansion on the differences
>between 15 and 20 amp branches is here:

At least where I used to live, 15A circuits weren't allowed except for
wired lighting.

>http://www.paragonweb.com/Kiln_Pointer.cfm?PID=446

BTW, NEMA 5-15R is allowed on a 20A circuit. IOW, because you have a
NEMA 5-15R receptacle, doesn't mean that it's a 15A circuit, just that
the outlet is only rated for 15A.  It may be a simple matter of
replacing the receptacle on the existing circuit.  Though anything
else on the circuit may cause a problem.

[toc] | [prev] | [next] | [standalone]

#462178

On Sun, 28 May 2017 17:26:06 -0400, krw@notreal.com wrote:


>AIUI, the 80% capacity rule is for dedicated circuits.  Any such spec
>for utility circuits would be meaningless.   Likewise, it also doesn't
>apply to devices plugged into the utility circuits.

Since the same breaker is used in both cases, the differences are
moot.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com 
Tellico Plains, Occupied TN
See website for email address

[toc] | [prev] | [next] | [standalone]

#462193

On Mon, 29 May 2017 12:12:12 -0400, Neon John <no@never.com> wrote:

>On Sun, 28 May 2017 17:26:06 -0400, krw@notreal.com wrote:
>
>
>>AIUI, the 80% capacity rule is for dedicated circuits.  Any such spec
>>for utility circuits would be meaningless.   Likewise, it also doesn't
>>apply to devices plugged into the utility circuits.
>
>Since the same breaker is used in both cases, the differences are
>moot.

No, it's not.  It's about design.  A dedicated circuit has to be
designed for its load and they want the 80% derating.  The current in
a multi-drop utility branch can't be anticipated so such derating is
meaningless.  

[toc] | [prev] | [next] | [standalone]

#462146

On Thu, 25 May 2017 13:05:28 +0100, RBlack wrote:

> Hi,
> 
> We are working on a medical product, which will draw about 3 kW from the
> mains.  This is new territory for us, all our previous products were a

<snip>

> It has been suggested (not by me I hasten to add) that we split the
> loads within the product up and give it two 110V inlets, to get around
> the customer having to install a 'special' outlet for it.  This sounds
> like a Really Bad Idea and a regulatory nightmare to me, so if 220V
> outlets are commonly available anyway I can shoot it down before it gets
> too far.

That is a Really Bad Idea, medical or not.  And the reason it'll be a 
regulatory nightmare is because it _should_ be one.

North American wiring usually puts multiple sockets on one circuit, so 
chances are very high that both plugs would go into the same circuit, and 
just blow a breaker.

So, yea, you need to knock the power draw down by a _lot_ or accept the 
fact that your gizmo will need special circuits.

-- 
www.wescottdesign.com

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#462202

RBlack <news@rblack01.plus.com> writes:

>Hi,

>We are working on a medical product, which will draw about 3 kW from the 
>mains.  This is new territory for us, all our previous products were a 
>few hundred watts max so an off-the-shelf auto-ranging PSU with a 
>suitable IEC lead was OK for any country in the world.

>3 kW is OK for a standard outlet in 220V countries, but for North 
>America, Japan etc we are over the limit for a standard 110V outlet.

This always PO'ed me. I want a real electric snowblower, and
lawnmower. I lust for a British 30A 220V ring socket.... 

But all we have is wimpy circuits providing flea power. 

My only hope is more garages are getting electric car chargers;
lotsakilowatts!
-- 
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

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#462203

On Mon, 29 May 2017 20:24:21 +0000 (UTC), David Lesher
<wb8foz@panix.com> wrote:

>RBlack <news@rblack01.plus.com> writes:
>
>>Hi,
>
>>We are working on a medical product, which will draw about 3 kW from the 
>>mains.  This is new territory for us, all our previous products were a 
>>few hundred watts max so an off-the-shelf auto-ranging PSU with a 
>>suitable IEC lead was OK for any country in the world.
>
>>3 kW is OK for a standard outlet in 220V countries, but for North 
>>America, Japan etc we are over the limit for a standard 110V outlet.
>
>This always PO'ed me. I want a real electric snowblower, and
>lawnmower. I lust for a British 30A 220V ring socket.... 

Oh, good grief.  Just add a 240V circuit.
>
>But all we have is wimpy circuits providing flea power. 

Nonsense.

>My only hope is more garages are getting electric car chargers;
>lotsakilowatts!

There is nothing magic about EV chargers.  Just do it.

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#462308

krw@notreal.com writes:

>>This always PO'ed me. I want a real electric snowblower, and
>>lawnmower. I lust for a British 30A 220V ring socket.... 

>Oh, good grief.  Just add a 240V circuit.

No, reality. No one makes/sells 240V lawnmowers & snowblowers
here, because they would require outlets that most houses lack.

(If I was building myself one it would have a 3-phase motor with
the VFD back at the garage.)
-- 
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

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