Ask the Experts-NGC-Home Wiring

[John Croucher]

I have a wall outlet that quit working instantly when the microwave was turned on.  The outlet is fed from the panel box to the outlet with no branch lines.  There is power at the breaker feeding the line.  No power at the wire end where it connects to the receptacle.  There are three different wires going up the wall from the basement up into the floor and behind the drywall toward the bad receptacle.  Will a non contact voltage detector work to find the wire that is not carrying current if there is no load at the receptacle?  And can I trace the wire from the panel box to find where there is most likely a wire staple that has penetrated the wires and finally shorted out/broke? 

The refrigerator also shares this receptacle.  My Wife and I both commented that the refrigerator was making a unusual noise the night before.  These leads me to believe that the wire was about to finally burn into from the high resistance.  Hitting the microwave start button finished it off.  I have found other wires in my home that have had staples in them and shorted out. 

I can reach most of the wire except where it goes up through the floor and drywall above.  Should I isolate any other wires from the spots that I check for voltage to prevent cross readings? 

3 wire romex house wiring, black, white, copper.

[dguzzi]

  I have had bad GFCI outlets that act up and cause strange things like that. Is the outlet in question downstream from one?

[jcctx]

Tighten connector screw at the breaker and the grounding screw as well; check actual connections at plug. If nothing found just run a new wire as that is cheaper than all the other options!!!

[Tom]

The wall/switch outlets usually wear out first.  The contacts in them bear the load and they fail.  I've rarely replaced breaker switches in the load center.  My guess is that the wall outlet contacts died and it needs replacing.  As mentioned could be a GFCI in-line that died.

Sounds like you stuck a meter on the outlet?  That would be were you start to see if the line is hot.  Fortunately, this electrical work is easier than a wiring loom on a motorcycle.  Good luck.   

[Howard R]

Yes, a non-contact voltage monitor will work, get one that is designed to be held in proximity to the wire & it will tell you if voltage is present.  No need for a load on the circuit.  Good ones are about $20, cheap ones more like $10.  Did the breaker trip and you reset it, and if so does it stay on or trip again immediately?  If a staple had shorted out the wire, it probably wouldn't heal itself unless, as you suspect, the wire broke somewhere before the staple.  Shoule be pretty easy to find the fault & fix it.

[blackcat]

I was doing some plumbing work on one of the bathroom sinks when the wrench that was on the cold water line contacted the hot water line and it sparked scaring the shyte out of me. I got out a meter and realized that the lines were live, then I checked a couple of more metal spots, including the door hinges and they all were showing power!  I had recently replaced all of the hot and cold water lines in the house with PEX and wondered if I had done something to cause the problem, but realized that wasn't the cause of the issue. Turns out that when the electricians installed the GFCI in the box next to the sink, it was a tight fit and the hot pole touched the side of the box which transferred to the metal lath in the plaster walls. They did wrap electrical wire around the receptacle but one small portion was exposed, probably from forcing it into the older style box.

The point is, anything can happen when it comes to electricity so keep looking for the problem.

[Tom]

 Checking with a meter helps determining what failed.   

[John Croucher]

Chased the wire back to panel. Black wire from receptacle to panel has a spliced black Wire nut connection in panel.

Is a wire nut code?

Now the strange part. The panel box has a two 100 amp breaker going to detached man cave.  I turned off the main breaker and back on.  All the house exterior sensor lights are staying on and man cave lights don't come on.

In man cave two gfi breakers working, no power on three light breakers.   The water heater breaker was off. I turned it on and the lights came on?  What the heck, I had to laugh.  Any ideas?

[Mike Tashjian]

First problem microwave not working on circuit.  Many  times  I find receptacles that have wires pushed in as they were very common.  They tend to fail on either  the hot(black wire) or neutral(white wire).  The non contact tester will tell you if there is voltage present on a wire but will also get interference from a nearby wire passing close.  So a quick way to check is with a VOM set for AC and see if you get voltage across the hot(short straight opening) and neutral(taller straight opening) and then across the short and ground(round  hole). I like to check the offending outlet first and move towards the panel. I will remove wires that are pushed in and use the screw terminals on all outlets. Your problem could be at any downstream outlet.   Wire staples are not a common issue compared to failing receptacles.   Flipping a breaker is going to make many sensor light turn on, so that is why they lit up. turning them on and off again should reset them.  I can't tell from your picture but wire nuts are not usually allowed in panels except for generator transfer panel connections.  Some breakers allow 2 connections but some areas do not allow it.  Guessing the water heater breaker is double tapped and that would not be right in most cases.

[RinkRat II]

   Hi John, my only question is why the top #4 or 6 gauge wire not connected to the breaker or is that an optical illusion in your picture?

    Paul B

[antmanbee]

   Hi John, my only question is why the top #4 or 6 gauge wire not connected to the breaker or is that an optical illusion in your picture?

    Paul B

I thought the same thing. Also the wire looks too thin for a 100A breaker to a likely distant detached man cave. Is it aluminum? Hard to tell all this from the picture.

[John Croucher]

I thought the same thing. Also the wire looks too thin for a 100A breaker to a likely distant detached man cave. Is it aluminum? Hard to tell all this from the picture.

Looking at the picture, you may be right  The top wire looks broke. Maybe why the Man cave lights are flashing on and off.  Will pull cover and report back.