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off topic: old house wiring?

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  off topic:  old house wiring? hancock4@bbs.cpcn.com - 2015-12-09 11:01 -0800
    Re: off topic:  old house wiring? Jon Elson <jmelson@wustl.edu> - 2015-12-09 14:17 -0600
      Re: off topic:  old house wiring? Dan Espen <despen@verizon.net> - 2015-12-09 16:18 -0500
        Re: off topic:  old house wiring? hancock4@bbs.cpcn.com - 2015-12-09 13:38 -0800
          Re: off topic: old house wiring? philo <philo@privacy.net> - 2015-12-09 17:38 -0600
          Re: off topic:  old house wiring? Jon Elson <jmelson@wustl.edu> - 2015-12-10 13:54 -0600
    Re: off topic:  old house wiring? Morten Reistad <first@last.name.invalid> - 2015-12-09 21:43 +0100
      Re: off topic:  old house wiring? hancock4@bbs.cpcn.com - 2015-12-09 13:19 -0800
        Re: off topic:  old house wiring? "Osmium" <r124c4u102@comcast.net> - 2015-12-12 10:38 -0600
          Re: off topic:  old house wiring? "gareth" <no.spam@thank.you.invalid> - 2015-12-12 16:53 +0000
          Re: off topic:  old house wiring? Morten Reistad <first@last.name.invalid> - 2015-12-12 18:06 +0100
            Re: off topic:  old house wiring? "Osmium" <r124c4u102@comcast.net> - 2015-12-12 11:31 -0600
            Re: off topic:  old house wiring? hancock4@bbs.cpcn.com - 2015-12-12 11:25 -0800
          Re: off topic:  old house wiring? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-12 18:41 +0000
            Re: off topic:  old house wiring? "Osmium" <r124c4u102@comcast.net> - 2015-12-12 17:14 -0600
              Re: off topic:  old house wiring? Bob Eager <news0005@eager.cx> - 2015-12-12 23:31 +0000
              Re: off topic:  old house wiring? Michael Black <et472@ncf.ca> - 2015-12-12 21:42 -0500
      Re: off topic: old house wiring? Peter Flass <peter_flass@yahoo.com> - 2015-12-09 16:22 -0500
        Re: off topic: old house wiring? hancock4@bbs.cpcn.com - 2015-12-09 13:42 -0800
          Re: off topic: old house wiring? Peter Flass <peter_flass@yahoo.com> - 2015-12-09 17:11 -0500
          Re: off topic: old house wiring? cmadams@cmadams.net (Chris Adams) - 2015-12-09 19:41 -0600
        Re: off topic: old house wiring? Morten Reistad <first@last.name.invalid> - 2015-12-10 01:54 +0100
          Re: off topic: old house wiring? Dave Garland <dave.garland@wizinfo.com> - 2015-12-09 22:42 -0600
            Re: off topic: old house wiring? Jon Elson <jmelson@wustl.edu> - 2015-12-14 17:28 -0600
              Re: off topic: old house wiring? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-15 08:19 +0000
                Re: off topic: old house wiring? Morten Reistad <first@last.name.invalid> - 2015-12-15 09:48 +0100
                Re: off topic: old house wiring? hancock4@bbs.cpcn.com - 2015-12-16 09:53 -0800
          Re: off topic: old house wiring? "Ranger" <r5432@gmail.com> - 2015-12-10 17:44 +1100
          Re: off topic: old house wiring? Peter Flass <peter_flass@yahoo.com> - 2015-12-10 15:23 -0500
            Re: off topic: old house wiring? scott@slp53.sl.home (Scott Lurndal) - 2015-12-10 20:49 +0000
            Re: off topic: old house wiring? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-10 23:48 +0000
              Re: off topic: old house wiring? Michael Black <et472@ncf.ca> - 2015-12-10 23:12 -0500
                Re: off topic: old house wiring? mausg@mail.com - 2015-12-11 10:12 +0000
                Re: off topic: old house wiring? "Osmium" <r124c4u102@comcast.net> - 2015-12-11 08:31 -0600
                  Re: off topic: old house wiring? "gareth" <no.spam@thank.you.invalid> - 2015-12-11 14:47 +0000
                    Re: off topic: old house wiring? "Osmium" <r124c4u102@comcast.net> - 2015-12-11 09:06 -0600
                      Re: off topic: old house wiring? "gareth" <no.spam@thank.you.invalid> - 2015-12-11 15:49 +0000
                        Re: off topic: old house wiring? hancock4@bbs.cpcn.com - 2015-12-11 09:37 -0800
              Re: off topic: old house wiring? mausg@mail.com - 2015-12-11 10:08 +0000
                Re: off topic: old house wiring? cmadams@cmadams.net (Chris Adams) - 2015-12-11 08:38 -0600
                  Re: off topic: old house wiring? mausg@mail.com - 2015-12-11 16:24 +0000
                Re: off topic: old house wiring? Morten Reistad <first@last.name.invalid> - 2015-12-11 15:17 +0100
                  Re: off topic: old house wiring? hancock4@bbs.cpcn.com - 2015-12-11 09:30 -0800
                    Re: off topic: old house wiring? Stephen Sprunk <stephen@sprunk.org> - 2015-12-11 12:43 -0600
                      Re: off topic: old house wiring? hancock4@bbs.cpcn.com - 2015-12-11 11:09 -0800
                        Re: off topic: old house wiring? Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-11 22:56 +0000
                      Re: off topic: old house wiring? Michael Black <et472@ncf.ca> - 2015-12-11 14:47 -0500
                        Re: off topic: old house wiring? "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:13 -0600
        Re: off topic: old house wiring? Stephen Sprunk <stephen@sprunk.org> - 2015-12-09 22:39 -0600
          Re: off topic: old house wiring? "Osmium" <r124c4u102@comcast.net> - 2015-12-09 23:12 -0600
            Re: off topic: old house wiring? Stephen Sprunk <stephen@sprunk.org> - 2015-12-10 00:59 -0600
          Re: off topic: old house wiring? Morten Reistad <first@last.name.invalid> - 2015-12-10 09:48 +0100
            Re: off topic: old house wiring? Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-10 12:40 +0000
            Re: off topic: old house wiring? Stephen Sprunk <stephen@sprunk.org> - 2015-12-10 11:02 -0600
              Re: off topic: old house wiring? Jon Elson <elson@pico-systems.com> - 2015-12-11 22:01 -0600
                Re: off topic: old house wiring? Stephen Sprunk <stephen@sprunk.org> - 2015-12-12 00:48 -0600
                  Re: off topic: old house wiring? Morten Reistad <first@last.name.invalid> - 2015-12-12 11:16 +0100
        Re: off topic: old house wiring? Jon Elson <jmelson@wustl.edu> - 2015-12-14 17:25 -0600
          Re: off topic: old house wiring? hancock4@bbs.cpcn.com - 2015-12-16 09:45 -0800
      Re: off topic:  old house wiring? scott@slp53.sl.home (Scott Lurndal) - 2015-12-10 14:06 +0000
      Re: off topic:  old house wiring? "capek@ieee.org <Peter Capek>" <peter.capek@gmail.com> - 2015-12-12 11:50 -0800
        Re: off topic:  old house wiring? "Osmium" <r124c4u102@comcast.net> - 2015-12-12 16:56 -0600

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#154911 — off topic: old house wiring?

At the end of WW II, in the late 1940s and early 1950s, a
zillion houses were built for the returning servicemen and
their new families.  Actually, during the war itself a 
fair number of "defense" housing units were built to
house workers at key defense plants.

Anyway, based on the other thread, I was wondering 
what kind of shape is their electrical wiring in?
It's been 60-65 years, and insulation can decay
over time.

While I suspect most homeowners have upgraded their
main service to more power, I don't think they 
underwent the expense to rewire every room in the
house--they could get rather expensive, especially
for simple houses and modest-income residents.

(As mentioned, our family didn't bother upgrading
to 100 amp as it was rather expensive, we could
make do with our one a/c and 60 amp.  but we no 
longer live in that house.)


Also, what about buildings?  I drove by my old
elementary school which was built with fluorescent
lights in 1948; I noticed the fixtures were replaced.
Presumably, given that the school district is broke,
that they had no choice but to do a replacement.
Modern lamps are supposed to be more energy efficient.

For commercial buildings, I sense that over time
changing requirements require a full reconstruction
anyway, which would include rewiring.

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#154914

hancock4@bbs.cpcn.com wrote:

> At the end of WW II, in the late 1940s and early 1950s, a
> zillion houses were built for the returning servicemen and
> their new families.  Actually, during the war itself a
> fair number of "defense" housing units were built to
> house workers at key defense plants.
> 
> Anyway, based on the other thread, I was wondering
> what kind of shape is their electrical wiring in?
> It's been 60-65 years, and insulation can decay
> over time.
Well, this stuff is likely the old cloth-covered Romex, with some kind of 
early plastic-y insulation on the wires.  I've seen a fair amount of it.
As long as you don't handle it roughly, it seems to be quite stable.  Bit, 
it WON'T have ground wires in it, so any rework would require it to all come 
out.  My mother in law's house was built in the 60's, and has no grounds 
anywhere, either.

People keep telling her she can just put 3-prong outlets in, but that's 
wrong, without ground wires.

Jon

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#154922

Jon Elson <jmelson@wustl.edu> writes:

> hancock4@bbs.cpcn.com wrote:
>
>> At the end of WW II, in the late 1940s and early 1950s, a
>> zillion houses were built for the returning servicemen and
>> their new families.  Actually, during the war itself a
>> fair number of "defense" housing units were built to
>> house workers at key defense plants.
>> 
>> Anyway, based on the other thread, I was wondering
>> what kind of shape is their electrical wiring in?
>> It's been 60-65 years, and insulation can decay
>> over time.
> Well, this stuff is likely the old cloth-covered Romex, with some kind of 
> early plastic-y insulation on the wires.  I've seen a fair amount of it.
> As long as you don't handle it roughly, it seems to be quite stable.  Bit, 
> it WON'T have ground wires in it, so any rework would require it to all come 
> out.  My mother in law's house was built in the 60's, and has no grounds 
> anywhere, either.
>
> People keep telling her she can just put 3-prong outlets in, but that's 
> wrong, without ground wires.

You'd think so, but not quite:

http://www.thisoldhouse.com/toh/article/0,,20065922,00.html

In short, if you've got BX cable, and check if it's grounded,
you're good to go.

If you don't have ground, you just need to label the outlet.

-- 
Dan Espen

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#154925

On Wednesday, December 9, 2015 at 4:18:08 PM UTC-5, D_J_E wrote:
> If you don't have ground, you just need to label the outlet.

The old outlets didn't have a spot for the grounding plug.

People used to buy adapters, and just leave the ground wire
dangling.

In our old house, our wiring did not have grounding.  But
there was something connected to the cold water pipe with
a "DO NOT REMOVE" tag on it.

obcomp:  IBM typewriters did not have a ground plug, but were
marked "double insulated, no grounding required".

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#154931 — Re: off topic: old house wiring?

On 12/09/2015 03:38 PM, hancock4@bbs.cpcn.com wrote:
> On Wednesday, December 9, 2015 at 4:18:08 PM UTC-5, D_J_E wrote:
>> If you don't have ground, you just need to label the outlet.
>
> The old outlets didn't have a spot for the grounding plug.
>
> People used to buy adapters, and just leave the ground wire
> dangling.
>
> In our old house, our wiring did not have grounding.  But
> there was something connected to the cold water pipe with
> a "DO NOT REMOVE" tag on it.
>
> obcomp:  IBM typewriters did not have a ground plug, but were
> marked "double insulated, no grounding required".
>


My house was built in 1898 and wired in 1932.

The 1932 wiring is hardwall conduit and BX with rubber and cloth wire.

I recently did some rewiring and replaced quite a bit of the original 
wiring and it was still in good shape.

In the 35 years I've been in this house there was only one problem.

Back in those days they twisted and soldered the connections, then 
taped. One of the solder joints went bad and the connection was lost.

I have no way of knowing if it was a poor connection to begin with or if 
heat caused the problem...but at any rate the wiring itself was still ok

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#154981

hancock4@bbs.cpcn.com wrote:

> On Wednesday, December 9, 2015 at 4:18:08 PM UTC-5, D_J_E wrote:
>> If you don't have ground, you just need to label the outlet.
> 
> The old outlets didn't have a spot for the grounding plug.
> 
> People used to buy adapters, and just leave the ground wire
> dangling.
> 
> In our old house, our wiring did not have grounding.  But
> there was something connected to the cold water pipe with
> a "DO NOT REMOVE" tag on it.
That is the ground for the phone co's lightning arrestor block.

Jon

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#154917

In article <4bfe5610-cbb3-4dd2-a711-f9af1720f640@googlegroups.com>,
 <hancock4@bbs.cpcn.com> wrote:
>At the end of WW II, in the late 1940s and early 1950s, a
>zillion houses were built for the returning servicemen and
>their new families.  Actually, during the war itself a 
>fair number of "defense" housing units were built to
>house workers at key defense plants.
>
>Anyway, based on the other thread, I was wondering 
>what kind of shape is their electrical wiring in?
>It's been 60-65 years, and insulation can decay
>over time.
>
>While I suspect most homeowners have upgraded their
>main service to more power, I don't think they 
>underwent the expense to rewire every room in the
>house--they could get rather expensive, especially
>for simple houses and modest-income residents.
>
>(As mentioned, our family didn't bother upgrading
>to 100 amp as it was rather expensive, we could
>make do with our one a/c and 60 amp.  but we no 
>longer live in that house.)
>
I am a little taken aback by these numbers. We have
a three-phase 63A intake, which is HUGE in Europe.
We do get 63 x 235 x 1.71 ~= 25 kW. by that. Enough
for several rapid electric car chargers plus a lot
of house.

24A x 3 can be used in some flats.

>Also, what about buildings?  I drove by my old
>elementary school which was built with fluorescent
>lights in 1948; I noticed the fixtures were replaced.
>Presumably, given that the school district is broke,
>that they had no choice but to do a replacement.
>Modern lamps are supposed to be more energy efficient.
>
>For commercial buildings, I sense that over time
>changing requirements require a full reconstruction
>anyway, which would include rewiring.

One thing that was invented ca 1936 was PEX; the isolation
material we still use. If the isolation is good PEX then
the wires are still good, after 75+ years.

-- mrr


 

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#154923

On Wednesday, December 9, 2015 at 3:45:23 PM UTC-5, Morten Reistad wrote:
> I am a little taken aback by these numbers. We have
> a three-phase 63A intake, which is HUGE in Europe.
> We do get 63 x 235 x 1.71 ~= 25 kW. by that. Enough
> for several rapid electric car chargers plus a lot
> of house.

In the US, the basic voltage is 120V, but I think in Europe it's 240V.
So, I think you can get twice as much power for the same amperage.

In the US, very heavy appliances--water heater, stove, a/c, dryer,
electric heat, are 240.  In some areas, all of those (except a/c)
are powered by gas, which is cheaper than electricity for heating.
In many places, oil heat is used.

In some ways, we now use less power than before, such as flat screen
TV's vs the big color tubes, and CFLs for lighting.  Some homes
have floodlights for the yards, and they used to be 150W lamps,
now much less.

Our appliances eat up power.  I remember my mother originally had
a hand rug sweeper, later she got an electric.  Hair dryers came
out at some point.  Toaster ovens replaced simple toasters.
Electric mixers vs. hand units, and electric power tools rather
than hand tools.  computers instead of a manual typewriter.

Question--would anyone know how many watts a simple table radio 
using tubes consumed?

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#155112

<hancock4@bbs.cpcn.com> wrote:

> Question--would anyone know how many watts a simple table radio
> using tubes consumed?

I would say something less than 117 Watts.  There were several "sets" of
vacuum tubes, designed especially to work together in a transformerless
AC-DC design. They all had the same heater (filament)current and when the
set was used the voltages added up to 117 (volts). I think the most common
was 35W4, 50L6, 12SA7, 12SG7 and12SQ7,  There's some guesswork in there and
I think the 12SG7 is wrong, but a few minutes work doesn't come up with a
better guess.  There were also special provisions to allow the use of a dial
lamp with the mix, a tap on the heater of the 35W4.   The heater current was
the same on all of them, that was the key point of the design, and it was
0.15 Amp. The only other current draw was the plate current and it is hard
to imagine it using up the remainder if an Ampere, so ISTM that 117 Watts is
on the high side of the error band  (The heaters and dial lamp only use 17
Watts.)

I expect the above tube complement, after correcting for my errors,  was
used on millions of US table radios going into WW II.  Eerlier (1935 or so)
there had been radios that used a special resistive power cord to get things
to work out, the power cord got warm when the radio was in use. These power
cords were typically  wrapped in brown fabric so they looked odd.

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#155115

"Osmium" <r124c4u102@comcast.net> wrote in message 
news:dd30soFpud0U1@mid.individual.net...
> I would say something less than 117 Watts.  There were several "sets" of
> vacuum tubes, designed especially to work together in a transformerless
> AC-DC design. They all had the same heater (filament)current and when the
> set was used the voltages added up to 117 (volts).

In Brit, the P series were 300mA for series heater connection, eg PCF80
a triode-hexode, with the E series being 6.3V heaters, such as the ECF80

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#155118

In article <dd30soFpud0U1@mid.individual.net>,
Osmium <r124c4u102@comcast.net> wrote:
><hancock4@bbs.cpcn.com> wrote:
>
>> Question--would anyone know how many watts a simple table radio
>> using tubes consumed?
>
>I would say something less than 117 Watts.  There were several "sets" of
>vacuum tubes, designed especially to work together in a transformerless
>AC-DC design. They all had the same heater (filament)current and when the
>set was used the voltages added up to 117 (volts). I think the most common
>was 35W4, 50L6, 12SA7, 12SG7 and12SQ7,  There's some guesswork in there and
>I think the 12SG7 is wrong, but a few minutes work doesn't come up with a
>better guess.  There were also special provisions to allow the use of a dial
>lamp with the mix, a tap on the heater of the 35W4.   The heater current was
>the same on all of them, that was the key point of the design, and it was
>0.15 Amp. The only other current draw was the plate current and it is hard
>to imagine it using up the remainder if an Ampere, so ISTM that 117 Watts is
>on the high side of the error band  (The heaters and dial lamp only use 17
>Watts.)
>
>I expect the above tube complement, after correcting for my errors,  was
>used on millions of US table radios going into WW II.  Eerlier (1935 or so)
>there had been radios that used a special resistive power cord to get things
>to work out, the power cord got warm when the radio was in use. These power
>cords were typically  wrapped in brown fabric so they looked odd.

In my youth I reparied several old ca 1945-1952 tube radios, and was
a regular user of the public tube tester at the tube pusher in town.

I also measured the effect draw; this was typically 60-80 watts with the
radio well warm and the sound turned down. It peaked at nearly 200W when
turned on, went rapidly (2-3 seconds) to below 100, and settled on something
in the 60-80 range. With full sound they typically drew 10-15 W more. 

These were Blaupunkts, Grundigs and Norsk Radiofabrikk ones. 

Pre-WW2 ones typically drew more.

-- mrr

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#155119

"Morten Reistad" wrote:

> In my youth I reparied several old ca 1945-1952 tube radios, and was
> a regular user of the public tube tester at the tube pusher in town.
>
> I also measured the effect draw; this was typically 60-80 watts with the
> radio well warm and the sound turned down. It peaked at nearly 200W when
> turned on, went rapidly (2-3 seconds) to below 100, and settled on 
> something
> in the 60-80 range. With full sound they typically drew 10-15 W more.

Yes, I forgot the peak!  The dial lamp flashed scarily bright for a fraction 
of a second when the set was first turned on.  One side effect of the 
arrangement I described was that you shouldn't simply ignore a bunted out 
dial lamp; it was an essential part of the set, not a luxury. 

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#155122

On Saturday, December 12, 2015 at 12:14:12 PM UTC-5, Morten Reistad wrote:
 
> In my youth I reparied several old ca 1945-1952 tube radios, and was
> a regular user of the public tube tester at the tube pusher in town.
> Pre-WW2 ones typically drew more.

My family had a GE AM-FM tube table radio that I think dated from
the early 1960s.  Nothing fancy.  Why it wasn't transistor, I don't 
know.  I think (but don't recall fo sure) that it had AFC with the FM.
(In 1965 I got a plain tape recorder that was tube based.  Around
1966 we got a portable TV set that had a few tubes ni it beyond 
the picture tube.)

Thanks to all for their comments.

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#155121

On 2015-12-12, Osmium <r124c4u102@comcast.net> wrote:

> I think the most common was 35W4, 50L6, 12SA7, 12SG7 and12SQ7,
> There's some guesswork in there and I think the 12SG7 is wrong,
> but a few minutes work doesn't come up with a better guess.

You're looking for 12SK7.  And 35W4 was the rectifier in the
later sets using 7-pin miniature tubes; the one used in the
octal version you're thinking of was 35Z5.

(The 7-pin miniature version used 12BE6, 12BA6, 12AV6, 50C5,
and 35W4.)

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

-- 
/~\  cgibbs@kltpzyxm.invalid (Charlie Gibbs)
\ /  I'm really at ac.dekanfrus if you read it the right way.
 X   Top-posted messages will probably be ignored.  See RFC1855.
/ \  HTML will DEFINITELY be ignored.  Join the ASCII ribbon campaign!

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#155127

"Charlie Gibbs" wrote:

> On 2015-12-12, Osmium <r124c4u102@comcast.net> wrote:
>
>> I think the most common was 35W4, 50L6, 12SA7, 12SG7 and12SQ7,
>> There's some guesswork in there and I think the 12SG7 is wrong,
>> but a few minutes work doesn't come up with a better guess.
>
> You're looking for 12SK7.  And 35W4 was the rectifier in the
> later sets using 7-pin miniature tubes; the one used in the
> octal version you're thinking of was 35Z5.
>
> (The 7-pin miniature version used 12BE6, 12BA6, 12AV6, 50C5,
> and 35W4.)
>
> https://en.wikipedia.org/wiki/All_American_Five

Thanks, 12SK7 it is. That is strange how my mind messed up the two series 
and let 35W4 be octal.  Even after reading your post, the 35Z5 refuses to 
come to my mind, as though I had never heard of it.

The linked article says that the chassis may be connected to one side of the 
line - I don't think I ever saw that happen in practice on a radio.  I don't 
even know haw dangerous a 120 V power line really is to a healthy teenager. 

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#155128

On Sat, 12 Dec 2015 17:14:46 -0600, Osmium wrote:

> The linked article says that the chassis may be connected to one side of
> the line - I don't think I ever saw that happen in practice on a radio. 
> I don't even know haw dangerous a 120 V power line really is to a
> healthy teenager.

I've seen that many times, a long time ago. No transformer, just a 
dropper/barretter[1]. And with a two pin plug, often the chassi could be 
at line rather than neutral.

Oh, this is in the UK, with 230V power! And only a 30A fuse upstream.

[1] https://en.wikipedia.org/wiki/Iron-hydrogen_resistor
-- 
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
 http://www.mirrorservice.org

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#155133

On Sat, 12 Dec 2015, Osmium wrote:

> "Charlie Gibbs" wrote:
>
>> On 2015-12-12, Osmium <r124c4u102@comcast.net> wrote:
>> 
>>> I think the most common was 35W4, 50L6, 12SA7, 12SG7 and12SQ7,
>>> There's some guesswork in there and I think the 12SG7 is wrong,
>>> but a few minutes work doesn't come up with a better guess.
>> 
>> You're looking for 12SK7.  And 35W4 was the rectifier in the
>> later sets using 7-pin miniature tubes; the one used in the
>> octal version you're thinking of was 35Z5.
>> 
>> (The 7-pin miniature version used 12BE6, 12BA6, 12AV6, 50C5,
>> and 35W4.)
>> 
>> https://en.wikipedia.org/wiki/All_American_Five
>
> Thanks, 12SK7 it is. That is strange how my mind messed up the two series and 
> let 35W4 be octal.  Even after reading your post, the 35Z5 refuses to come to 
> my mind, as though I had never heard of it.
>
> The linked article says that the chassis may be connected to one side of the 
> line - I don't think I ever saw that happen in practice on a radio.  I don't 
> even know haw dangerous a 120 V power line really is to a healthy teenager. 
>
I once took a VTVM (voltmeter that had a power supply that ran from the AC 
line) and I just wasn't thinking, so I connected the ground wire to the 
"ground" of an AC/DC tv set (that was common for portable sets, at least 
in the B&W days).  The insulation on that ground wire burned off fast, the 
fuse took longer to go.

Nowadays, the equivalent of those old radios is switching supplies.  The 
initial circuitry is right across the AC line, but it converts it to DC, 
which then powers an AC oscillator at a higher frequency, so the voltage 
can be stepped down with a much smaller transformer (since it can operate 
at hundreds of Hertz rather than 50/60Hertz of the line frequency).  Up 
till that transformer, the circuitry is as unsafe as those old radios.

   Michael

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#154924 — Re: off topic: old house wiring?

Morten Reistad <first@last.name.invalid> wrote:
> In article <4bfe5610-cbb3-4dd2-a711-f9af1720f640@googlegroups.com>,
>  <hancock4@bbs.cpcn.com> wrote:
>> At the end of WW II, in the late 1940s and early 1950s, a
>> zillion houses were built for the returning servicemen and
>> their new families.  Actually, during the war itself a 
>> fair number of "defense" housing units were built to
>> house workers at key defense plants.
>> 
>> Anyway, based on the other thread, I was wondering 
>> what kind of shape is their electrical wiring in?
>> It's been 60-65 years, and insulation can decay
>> over time.
>> 
>> While I suspect most homeowners have upgraded their
>> main service to more power, I don't think they 
>> underwent the expense to rewire every room in the
>> house--they could get rather expensive, especially
>> for simple houses and modest-income residents.
>> 
>> (As mentioned, our family didn't bother upgrading
>> to 100 amp as it was rather expensive, we could
>> make do with our one a/c and 60 amp.  but we no 
>> longer live in that house.)
>> 
> I am a little taken aback by these numbers. We have
> a three-phase 63A intake, which is HUGE in Europe.
> We do get 63 x 235 x 1.71 ~= 25 kW. by that. Enough
> for several rapid electric car chargers plus a lot
> of house.
> 

100 amps seems to have been the minimum here for many years.  I don't know
if newer construction supports more, though I wouldn't be surprised.

-- 
Pete

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#154926 — Re: off topic: old house wiring?

On Wednesday, December 9, 2015 at 4:22:47 PM UTC-5, Peter Flass wrote:
> 100 amps seems to have been the minimum here for many years.  I don't know
> if newer construction supports more, though I wouldn't be surprised.

I don't know what new US construction has, but I think it's dependent
on how much heating appliances (eg stove) can use gas.  We have 
electric heat and need a lot of current just for that.

The electric company once gave us an electric heat discount in
the winter, which helped, but I think they discontinued that.

A lot of folks got heat pumps, which do save some energy, but the
units do seem to require frequent repairs and last only about
12 years, and are very expensive.  I question if the energy
saved (over plain resistance heat) justifies the higher maint
and purchase cost.

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#154927 — Re: off topic: old house wiring?

<hancock4@bbs.cpcn.com> wrote:
> On Wednesday, December 9, 2015 at 4:22:47 PM UTC-5, Peter Flass wrote:
>> 100 amps seems to have been the minimum here for many years.  I don't know
>> if newer construction supports more, though I wouldn't be surprised.
> 
> I don't know what new US construction has, but I think it's dependent
> on how much heating appliances (eg stove) can use gas.  We have 
> electric heat and need a lot of current just for that.
> 
> The electric company once gave us an electric heat discount in
> the winter, which helped, but I think they discontinued that.
> 
> A lot of folks got heat pumps, which do save some energy, but the
> units do seem to require frequent repairs and last only about
> 12 years, and are very expensive.  I question if the energy
> saved (over plain resistance heat) justifies the higher maint
> and purchase cost.
> 

I think they're also very sensitive to the temperature differential between
inside and outside. If it's 45° or 75° outside it's not too hard to keep
the inside temp in the 70s.  If it's 15° or 105° it's a little harder.

-- 
Pete

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