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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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7th Apr 2015, 9:31 pm | #61 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,195
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Re: Late 50s(?) domestic electrical distribution boards
Hi Most meters measure the current in the phase (live) conductor and the neutral is simply a link and low current connection to the voltage coil.
Done this way it will discourage anyone trying to shunt or bypass the current coil and reduce the electricity bill and they could get a severe shock. Ed |
8th Apr 2015, 12:17 am | #62 |
Hexode
Join Date: Jan 2012
Location: Weymouth, Dorset, UK.
Posts: 422
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Re: Late 50s(?) domestic electrical distribution boards
Yes that's what I was trying to get across in my earlier post I don't think its a common arrangement just something the pocos do to save on a bit of wire
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8th Apr 2015, 12:33 am | #63 |
Heptode
Join Date: Dec 2010
Location: Barnstaple, N.Devon, UK.
Posts: 557
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Re: Late 50s(?) domestic electrical distribution boards
Re post 60,
Hi John, that Wylex probably dates from the late 60's and is not an RCD but an Earth Leakage Trip. It's also rated at 100ma so not up to modern regs. David. |
8th Apr 2015, 6:46 am | #64 |
Heptode
Join Date: Apr 2003
Location: Cornwall, UK.
Posts: 989
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Re: Late 50s(?) domestic electrical distribution boards
That is certainly an RCD. These Wylex RCDs first appeared in the mid 1970's and we're very good quality. This style was available into the 1990s.
You are correct identifying that its rated tripping current is 100mA, so in this situation where it is probably protecting 13 amp socket outlets, would not comply. SimonT
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The honesty of imperfection.......... |
8th Apr 2015, 7:35 pm | #65 |
Heptode
Join Date: Dec 2010
Location: Barnstaple, N.Devon, UK.
Posts: 557
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Re: Late 50s(?) domestic electrical distribution boards
Oops. I missed the Current Operated bit there. I won't make the excuse that it was late, more a case of failing eyesight.
David. |
9th Apr 2015, 12:12 am | #66 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,273
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Re: Late 50s(?) domestic electrical distribution boards
100mA would be fitted to guard against a poor earth loop resistance or fire, a bit like a voltage operated ELCB. 30mA of course is the maximum for personal shock protection but wouldn't have been mandatory when that Wylex was installed.
When installing 3 phase with earth rod in the early 90's I used a T300mA RCD as the mains incomer and then local 30mA RCDs for all final circuits.
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Kevin |
9th Apr 2015, 9:10 am | #67 |
Nonode
Join Date: Aug 2010
Location: Resolven, Wales; and Bristol, England
Posts: 2,609
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Re: Late 50s(?) domestic electrical distribution boards
That isn't an RCD - It's an ELCD (Earth Leakage) which is not current under the 17th Ed!
ELCD's this old are usually useless for their specified purpose as well, just try testing the trip time on one!!
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Richard Index: recursive loop: see recursive loop Last edited by mole42uk; 9th Apr 2015 at 9:11 am. Reason: spelling |
9th Apr 2015, 9:42 am | #68 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,005
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Re: Late 50s(?) domestic electrical distribution boards
ELCDs often also fail to trip if there's a fortuitous additional low-resistance path from the earth of the domestic wiring to another well-earthed conductor. A good example being when you have an immersion-heater which someone has wired up using a 13-amp plug plugged into an ELCB-protected ring-main socket, as I discovered some years back.
ELCBs also don't play well with amateur radio RF earth connections. |
9th Apr 2015, 7:42 pm | #69 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,273
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Re: Late 50s(?) domestic electrical distribution boards
I think RCD and current-operated earth leakage circuit breaker are names for the same thing
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Kevin |