House Wiring Problem

luvflyin

luvflyin

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Got a wall outlet that is a half hot. One of the plug ins is controlled by a wall switch. When it is turned off it still has voltage. A very little bit, but the needle on the volt meter does move. ???
 
How are you determing it "has voltage." Long runs of unterminated wiring can induce enough current to light up some cheesy neon bulb testers.
 
It's called capacitive coupling/leakage. The same reason a neon bulb lights up when one end touches the live wire and the other end touches an insulated person.

Now, it could be that someone mis-wired the switch to to break the neutral instead of the live. Make a test fixture with a 5W LED bulb (the ones that have LED filaments) and see if it lights up between live/neutral and live/ground.
 
Get an outlet tester, like the one I linked below. It will tell you if the outlet is mis-wired.

This is a less expensive model but it will do what you need. There are fancier ones with more information available, too.

 
I suspect the switch is bad
 
Can something miswired elsewhere in the house be back feeding the neutral? Is that possible?
 
flyingron said:
How are you determing it "has voltage." Long runs of unterminated wiring can induce enough current to light up some cheesy neon bulb testers.
Click to expand...
It’s just volt meter with a needle. The needle moves so there is voltage.
 
Larry in TN said:
Get an outlet tester, like the one I linked below. It will tell you if the outlet is mis-wired.

This is a less expensive model but it will do what you need. There are fancier ones with more information available, too.

Click to expand...
I got one of those for a problem I had with some wiring I had done on another house a long time ago. I can’t find it, I probably left it there. I’ll get another one. Thx for the reminder.
 
luvflyin said:
It’s just volt meter with a needle. The needle moves so there is voltage.
Click to expand...
The problem is that meters have VERY HIGH IMPEDENCE (because you don't want them to disturb the circuit you are making the measurement on). The problem is that there is an induced voltage there, but as soon as you put a trivial load present it gets dissipated.

The classic place you find this is when there is no load (nothing plugged in) and the switch is off.
 
flyingron said:
The problem is that meters have VERY HIGH IMPEDENCE (because you don't want them to disturb the circuit you are making the measurement on). The problem is that there is an induced voltage there, but as soon as you put a trivial load present it gets dissipated.

The classic place you find this is when there is no load (nothing plugged in) and the switch is off.
Click to expand...
I experienced this installing new lights in our kitchen. The circuit had induced(phantom) voltage and it took me a while to figure it out and move forward with the project.
 
Larry in TN said:
Get an outlet tester, like the one I linked below. It will tell you if the outlet is mis-wired.
Click to expand...

Handy little item. I have a couple.

The fellow that built and wired the garage addition to our N GA house was obviously not a skilled electrician.

1) At the sub-panel, the neutral wire from the main panel dead-headed. Apparently all the receptacles relied on the bonded ground wire to work at all. I’ll see if I can dig out a photo.

2) All the garage outlets had the neutral and hot reversed. The tester caught that and it was easily remedied. Had never been an issue, but I suppose there was some shock hazard involved.
 
Here's how the panel was wired. Trace the large white neutral wire.

31822993634_406a3c5fb4_c.jpg


It sure seems all the neutrals and grounds were on the same bus. With the main neutral out of play, the only return appeared to be the rather small ga ground wire.

This is the "after" with grounds getting their own bus and neutrals properly feeding the receptacles.

51340979288_58ae058771_c.jpg
 
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FastEddieB said:
It sure seems all the neutrals and grounds were on the same bus. With the main neutral out of play, the only return appeared to be the rather small ga ground wire.
Click to expand...
Wow!

After my parents passed, when I was selling their house, the buyer's inspector found that the ground and neutral were bonded at the sub-panel. It was that way for 20 years!

At my house, I replaced all of my conventional outlets with decora-style with screwless plates. At one outlet I found an incredible mess. The electrician(?) had cut the Romex too short and made a big mess trying to fix it.


Outlet.jpg

I cleaned it up with Wagos and pigtails to the deivce.
 
It sounds like you have a shared neutral. That’s a no-no, and your problem illustrates why.
 
Larry in TN said:
Wow!

After my parents passed, when I was selling their house, the buyer's inspector found that the ground and neutral were bonded at the sub-panel. It was that way for 20 years!

At my house, I replaced all of my conventional outlets with decora-style with screwless plates. At one outlet I found an incredible mess. The electrician(?) had cut the Romex too short and made a big mess trying to fix it.


View attachment 153202

I cleaned it up with Wagos and pigtails to the deivce.
Click to expand...
I admit, I admire the ingenuity, but am appalled at the potential for trouble. There's a reason those wire nuts are green....
 
My garbage disposal and dishwasher are on a split outlet. One day, my son called me to the kitchen because the disposal wouldn't turn off, but didn't sound like it was fully running.

The tab that you break off to split the outlet was somehow passing some voltage and letting out some but not all of the magic smoke.
 

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We dont have this shared Neutral problem in chicagoland. EVERYTHING must be emt, even residential. But the bright side is the emt is also the ground.
 
pfarber said:
The neutral is basically ground... so wouldn't a breaker pop if a hot and a neutral made a baby?
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This appears to be a sub panel and neutrals and grounds need to be separated. If this was a main they could be bonded together.
 
pfarber said:
The neutral is basically ground... so wouldn't a breaker pop if a hot and a neutral made a baby?
Click to expand...
Yes, and no.

Neutral is a conductor. It is part of the circuit path whenever electricity is being used. Ground is not.

As you note, ground and neutral are tied at the first point of disconnect, but not at any subsequent sub-panels. One is part of the normal circuit path and the other is not.

A GFCI is looking for an unbalance between the current on the line (hot) and neutral which would be indicative of the return path being something other than the neutral, such as the ground or someone touching something they should not touch. That allows a much faster trip, before the current ramps up to the point where the circuit breaker would trip from excessive load. The standard C.B. protects the wiring, not a person touching the wrong thing.

A dead short from hot to neutral certainly will trip a C.B., but not until the short draws high current. Shorts can be other than dead shorts, though, and may not allow enough current flow to trip immediately.
 
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