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Circuit dead but circuit breaker not tripped...what to check?

Circuit dead but circuit breaker not tripped...what to check?

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  #1  
Old 09-22-01, 12:41 PM
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Unhappy

Hi folks,

I'm trying to diagnose and fix a recent electrical problem.

I went to turn on a table lamp in one of our bedrooms recently and the lamp "popped" (as if the bulb was blowing) and then everything in the room went dark. At the time, the only thing running in that room was a PC.

I went immediately to the circuit breaker panel and was surprised to see that none of the breakers had been tripped.

The circuit that isn't working consists of three recepticles in one room (one of which is controlled by a wall switch), and one in an adjacent room.

None of the recepticles has power.

I've already used a tester to test each circuit breaker (one end on the neutral bus bar and the other on the downstream side of each circuit breaker), and I got a "hot" indication on each one, so I'm assuming the circuit breakers are all functioning OK.

I've pulled each of the recepticle covers as well as the wall switch cover and noticed nothing obvious (everything still connected, no discoleration or burn marks).

Another post seemed to indicate checking for a loose connection at the neutral bar. Is this a good place to start?

Also, I've noticed that each of these recepticles uses the "rear-entry" style connection, not the side screws. Other posts indicated that these could be potential problem areas. (Although the entire house is presumably wired in this manner and we've never seem this problem before.)

House is circa 1970.

Thanks for any and all suggestions!

Regards,

Bates Marshall
 
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  #2  
Old 09-22-01, 01:06 PM
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Bates;
you have the infamous 'backstabbed' devices, and i highly suspect your prob is there. It's also unlikly that only 4 receptacles would be served by one breaker, so you probably have a partial circuit out here.
1)---Turn off the Main
2)---Pigtail your affected and/or suspect devices
3)---Turn on your main & check it out.
4) repeat 1--3 until results are positive

Good Luck !
 
  #3  
Old 09-23-01, 08:41 AM
Wgoodrich
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I agree with wirenuts. I also suspect a bad connection on a back stabbed receptacle as first suspect then a bad connection in a wire nut in one of the boxes including switch boxes and receptacle boxes as the second suspect.

Also about every 5 years or even more often, you should retighten the screws on the neutral bar, grounding bar and breakers in the panel. The heating and cooling during use tend to work these loose. After thirty years working in the field I would have gotten rich due to loose connections in panels and just replacing a switch or receptacle. Only problem is I had to pay my employees. I tried all those years to break those employees from wanting a pay check every Friday. I tried to explain just the priveledge of working for me should be enough. Never did convince them and blew all my income tightening screws in panels and replacing receptacles that were back stabbed on having to pay those employees. Never could figure out why I coudn't retrain them away from wanting that weekly pay check.

Also one thing that I want to point out as a very common mistake while performing diagnosis of a partial dead branch circuit. People always tend to check the dead receptacles but forget to check the last live receptacle. Often times the loss of power to that partial circuit is found in the last live receptacle at the power out cable of that live receptacle going to the first dead receptacle. Be sure to check the live receptacle suspected to be on that dead branch circuit. Your problem may be hiding there.

One other thought is John Nelson's favorite, A GFI may be on this circuit somewhere also that may have tripped when the lamp popped. This GFI device may be in the middle of that branch circuit. Worth checking also. Remember those GFIs tend to hide in the most unlikely location look hard for a hidden GFI when you look they love to hide.

Let us know what you find

Wg
 
  #4  
Old 09-23-01, 01:03 PM
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Thanks for the prompt responses WG and wirenuts!

I had taken the time to search through the archives last night before posting, so I had an idea of what the recommended trouble-shooting actions might be.

So...today I replaced all of the known dead back-stabbed receptacles with new wire-nut receptacles as well as the toggle switch which controls one of them.

I also checked all of the connections to the neutral bar in the service panel and found them all to be sound. Incidentally, my panel has both ground (bare copper) and neutral (white) wires terminating on what I'm referring to as the neutral bar. Is that correct terminology, and is that indeed what I'm seeing?

This house was originally built with no GFI circuits. However, an addition in 1981 brought a new external backyard outlet with a GFI. I have checked that GFI and pressed the reset button on it just to be extra safe. I'll continue looking for additional GFI circuits, but after scouring the house looking "in the most unlikely of places", I don't think there are any more lurking.

The suggestion to check the receptacles in some adjacent working areas is a good one. I'll go ahead and do this while I wait for more of your GREAT advice.

Thanks again for the help.

Regards,

// Bates
 
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