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Author Topic: Odd Power Outage  (Read 4126 times)

Art Welter

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Odd Power Outage
« on: July 16, 2016, 01:50:55 pm »

Odd Power Outage

Moved in to a refurbished 1954 rental house with a combination of old and new wiring. Although all the outlets have been replaced with new three pin outlets, none tested so far have a properly working earth ground, measuring between a few volts to around 60 volts from either neutral or hot to the earth ground. Testing from (what should be) the hot pin to the floor or walls or equipment chassis gives a voltage reading, testing from neutral gives no (or under a volt or so) voltage reading, so polarity seems correct even though lacking a ground.

The two south bedrooms ceiling fan/lights and outlets all share the same 15 amp circuit breaker.

The odd outage:
When a 120VAC/300mA 9VDC transformer (an old BellSouth unit used to charge a DirtDevil) was plugged in to the west outlet, it worked but the east outlet died, causing the uninterruptible power supply plugged in to that outlet warning beeper to sound. Removing the transformer from the outlet would result in the power coming back on. Plugging a lamp in to the east outlet caused no problem with the west outlet, and the transformer could be plugged into the west outlet with no problem.

Cause of the odd outage:
The new receptacles had been wired using the push-in back terminals designed (and labeled) for 14 AWG solid core wire. The old 16AWG wire was too small to make a decent connection in the 14 AWG hole, when the transformer was plugged in, it opened the (weak) connection feeding the east outlet. When the outlet was pulled from the box for inspection, the neutral feeding the other outlet fell out of the push-in terminal.

Re-wiring the outlets using the side screw terminals cured the problem, and reduced the voltage drop on the last outlet considerably.

Adventures in moving...

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Kevin Graf

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Re: Odd Power Outage
« Reply #1 on: July 16, 2016, 03:48:12 pm »

With an old two wire system, the new receptacles should have GFCI protection.
Small form-factor GFCIs are available to fit in the old smaller outlet boxes if needed.
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Corey Scogin

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Re: Odd Power Outage
« Reply #2 on: July 16, 2016, 04:42:40 pm »

If they'll fit, it's best to add leads for the receptacle and wire-nut the incoming, outgoing, and receptacle taps instead of the receptacle being inline...if that's not what you did.
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Mike Sokol

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Re: Odd Power Outage
« Reply #3 on: July 16, 2016, 05:40:02 pm »

Push-In terminations are evil...
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Stephen Swaffer

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Re: Odd Power Outage
« Reply #4 on: July 16, 2016, 10:19:31 pm »

True enough that 3 wire receptacles on a 2 wire system with no ground should be GFCI; however, in the typical modern home outside of the kitchen, bath and computer desk, how many appliance actually have a 3 wire plug?  If the appliances you are plugging in are 2 wire, then the ground is irrelevant.  I don't advocate doing that-but if you are aware and pay attention that would not be my first concern in this case.

If in fact that is wired with #16 wire that is a major issue. Nothing smaller than #14 is allowed for building wiring-and breakers of the appropriate size are going to special order.  Yes, I have seen it-in fact I pulled some #18 out of some kitchen wiring a little over a year ago.  They were spliced without boxes in the wall use automotive style tap connectors.

I agree with Mike-even though new push in style terminations reject #12 so they can only be used on 15 amp circuits they are still a really, really bad idea.
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TJ (Tom) Cornish

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Re: Odd Power Outage
« Reply #5 on: July 17, 2016, 08:06:21 am »


I agree with Mike-even though new push in style terminations reject #12 so they can only be used on 15 amp circuits they are still a really, really bad idea.
My house was built in 1995 but much of it was done with #14 wire and back stab connections. When we first moved in, running the laser printer in the office which was apparently at the end of 8 or so receptacles caused the voltage to drop below 90v. I rewired the receptacles using the screws and instead of a 30v drop for maybe a 1000w load, I get about 8.

Back stab wiring should be illegal. For the hour or two it may save when building a house, it creates a lot of hassle for the occupants and potential fire danger - that energy lost to the voltage drop has to go somewhere.
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Bob Leonard

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Re: Odd Power Outage
« Reply #6 on: July 17, 2016, 11:28:45 am »

Art,

I'm surprised that there was #16 wire used in the house to begin with. My house was built just after 1900, originally knob and tube, then armored, then romex, and all to a 6 circuit 30 amp box with fuses. None of that was less than #14, and all of that has been ripped out and replaced with #12 and the main run the length of the house being #12 THNN running through 1.5" EMT. If I were you Art I would make my first (long term) project replacing that wire with some good #12 copper. And when you run to the switches and outlets make sure you put a hook on the end, tighten the screws good and tight, and then tape around the outlet/switch to insulate the screw heads, and tape any wire nuts used as well. That keeps you from being knocked on your ass when you reach into the box to pull the outlet/switch back out again.
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Tom Bourke

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Re: Odd Power Outage
« Reply #7 on: July 17, 2016, 11:39:49 am »

Push-In terminations are evil...
Agree, my favorite type of outlet has holes in the back where you insert the strait stripped end of wire and then turn the screw to clamp it.  Those tend to be higher end outlets.
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Bob Leonard

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Re: Odd Power Outage
« Reply #8 on: July 17, 2016, 07:08:28 pm »

Agree, my favorite type of outlet has holes in the back where you insert the strait stripped end of wire and then turn the screw to clamp it.  Those tend to be higher end outlets.

I was going to mention that Tom. Many of the push in connections work fine with #12 and tightening the screw clamps the wire just as if the wire had been wrapped around the screw. You can usually tell these outlets and switches from the rest of the crowd because very one I have used or seen 1) Is made in the USA, and 2) The screws are backed out and not tightened at the factory.
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Stephen Swaffer

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Re: Odd Power Outage
« Reply #9 on: July 19, 2016, 10:29:48 pm »

Push-In terminations are evil...

I agree-I pulled this one out last summer-the only thing that prevented a fire here was it was in a metal box on metal liner on a steel frame building-no combustibles anywhere close.
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Steve Swaffer

ProSoundWeb Community

Re: Odd Power Outage
« Reply #9 on: July 19, 2016, 10:29:48 pm »


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