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Author Topic: Switched Neutral  (Read 995 times)

Frank DeWitt

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Switched Neutral
« on: June 10, 2014, 11:18:11 pm »

I'm working way up in the clock tower of a old church doing some mechanical work to the old clock and the light switch is flakey.  about 10 tries to get it to stay on.   I need to come back in a week with some more parts so I tell the church about it.  Would I change the switch when I am up there?  It's going to be hard to get an electrician to climb 5 ladders to change a switch.  also, there is another switch at the foot of the tower that kills all the power to the tower.  OK,  Turn off the power, climb the tower, check everything, trust nothing.  SWITCHED NEUTRAL ARE YOU KIDDING ME.

Fixed it, no one was hurt.

This stuff really does happen.
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Mike Sokol

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Re: Switched Neutral
« Reply #1 on: June 11, 2014, 12:09:50 am »

SWITCHED NEUTRAL ARE YOU KIDDING ME.
This stuff really does happen.

Many (or maybe even most) K&T wiring used switched neutrals all the time. And you have to be especially careful when you find new Romex installed in a old building that once had K&T. That's because sometimes an "electrician" would splice Romex onto the existing K&T wiring inside the walls to save money and fool the inspectors. And, of course, that's where RPBG (Reverse Polarity Bootleg Ground) outlets are born.

Frank - How did you find the switched neutral? Did you measure first or were you "surprised"?  I've found them both ways, I'm sorry to say.

Lyle Williams

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Re: Switched Neutral
« Reply #2 on: June 11, 2014, 04:29:00 am »

The temporary construction wiring standard down here in Australia now requires all switches and breakers to be double pole.  A countermeasure against crazy wiring practices.  Down here the construction standards are the most up-to-date (a decade+ ahead of the shows&carnivals standard).  It also seems to anticipate/address more poor practices than the other standards.
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Frank DeWitt

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Re: Switched Neutral
« Reply #3 on: June 11, 2014, 02:10:27 pm »

Frank - How did you find the switched neutral? Did you measure first or were you "surprised"?  I've found them both ways, I'm sorry to say.

I didn't take a meter up with me  (as it is, the trap doors are so small I can not put things in my pockets, and I need both hands to climb the vertical ladders so I put a few tools in a cloth bag at the end of a rope.  I knew the power was off and checked that the lights didn't work, but even when I KNOW the power is off I use a old habit I developed when I was a field service tech. 
1   Make sure the power is off
2.  Before doing anything else use a screwdriver to short the screw over the power wire to the box ground.
3.  Examine the big black spot on the screwdriver.

Repeat

When I was a field service tech the local maintenance guy would sometimes take offense. I would show him the screw driver with the scars from previous customer sites.

Usually it was the wrong breaker, not a switched neutral.
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Jeff Harrell

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Re: Switched Neutral
« Reply #4 on: June 16, 2014, 06:11:22 am »

i'v encountered that a number of times. i was helping my landlord install a celling fan in his house and the guy that wired it had the neutral on the switch. that can be a shocking experience.
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Stephen Swaffer

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Re: Switched Neutral
« Reply #5 on: June 16, 2014, 07:55:36 am »

Here is a fuse "box" I came across this week while estimating some electrical repairs.  A breaker panel had already been installed in tis home-I was very surprised to see this when I opened an unmarked wooden panel  I thought it was just an access panel.  Feeder comes in lower left through DP knife switch.  This a 120 V circuit-one main and 4 branch circuits, but fuses in every wire-obviously including the neutral.

Not poor workmanship-this was "state of the art" when it was installed!
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Steve Swaffer

Mike Sokol

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Re: Switched Neutral
« Reply #6 on: June 16, 2014, 03:08:47 pm »

Here is a fuse "box" I came across this week while estimating some electrical repairs.  A breaker panel had already been installed in tis home-I was very surprised to see this when I opened an unmarked wooden panel  I thought it was just an access panel.  Feeder comes in lower left through DP knife switch.  This a 120 V circuit-one main and 4 branch circuits, but fuses in every wire-obviously including the neutral.

Not poor workmanship-this was "state of the art" when it was installed!

It's a beauty, and totally terrifying by today's standards. One of the theaters in my town had exposed knife switches and fused hot/neutral wires feeding the theatrical lighting up until about 30 years ago. So the lighting operator stood in front of an bunch of hot knife switches with exposed, live bus bars everywhere. I remember when OSHA made them put a chicken-wire wall behind the lighting panel so a performer running by didn't push the lighting guy into the mass of hot/exposed wiring. That would have left a mark.

Good times...  8)

Jeff Harrell

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Re: Switched Neutral
« Reply #7 on: June 16, 2014, 10:00:51 pm »

Here is a fuse "box" I came across this week while estimating some electrical repairs.  A breaker panel had already been installed in tis home-I was very surprised to see this when I opened an unmarked wooden panel  I thought it was just an access panel.  Feeder comes in lower left through DP knife switch.  This a 120 V circuit-one main and 4 branch circuits, but fuses in every wire-obviously including the neutral.

Not poor workmanship-this was "state of the art" when it was installed!
EEEEEEEEK ! RUN AWAY RUN AWAY ! BAD BUNNY RABBIT !
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Stephen Swaffer

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Re: Switched Neutral
« Reply #8 on: June 17, 2014, 11:35:07 am »

I remember when OSHA made them put a chicken-wire wall behind the lighting panel so a performer running by didn't push the lighting guy into the mass of hot/exposed wiring.

Maybe I am not hearing/picturing this correctly?  But if I am standing in front of a mass of hot/exposed wiring, the last thing I want "protecting" me is a presumably grounded metal fence!?!
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Steve Swaffer

Jonathan Johnson

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Re: Switched Neutral
« Reply #9 on: June 17, 2014, 11:37:10 am »

This a 120 V circuit-one main and 4 branch circuits, but fuses in every wire-obviously including the neutral.

Not poor workmanship-this was "state of the art" when it was installed!

The picture isn't clear enough to tell for sure, but I would not be surprised if those are 30A time-delay fuses "protecting" 14 AWG wire.

I really like the plaster "box".
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Stop confusing the issue with facts and logic!
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