Dead Circuit, Breaker Shows Power, What to do?

Old 1925 vintage house, a lot of original wiring, 3 year old 200 amp box, never had any problems....

Until today, when I turn on a 60w ceiling light upstairs, and the light goes out after about 1 second. Figured the bulb had blown.... But later, i noticed that the entire circuit is dead!

Checked power with a voltmeter at the breaker box - 125 volts from breaker to ground. Checked at two different light switches on the circuit, both close and far away from breaker box. Both show no voltage.

Am I looking at a wire break somewhere? What do you guys think? Thanks.

 

You might want to read this post at the top of the page: http://www.doityourself.com/forum/el...rminology.html

 

Thanks Ray. I should have seen that first.

Ok. All breakers are still on. Switched them off to back on. 125 volts out of the wire coming from the breaker, so I think I can rule out the breaker.

All GFCIs in house, garage, and outside are untripped.

If a wire came loose at a fixture or a switch, wouldn't the rest of the lights work? I wired up most of the ceiling lights in this house and when I had one disconnected, the rest still worked.

OK, now I realize that some of the stuff on the circuit works and some doesn't. I guess there's a break somewhere between where stuff works and where it doesn't?

Lights upstairs all work except for the room where I was when I noticed the light blow...

 

Problem can be at the last working fixture or first non-working fixture. Wire nuts need to be removed and checked for corrosion or broken springs inside or just replaced with new ones.

 

Before the bulb blew, was it REALLY bright? If so, you may have an open neutral on that circuit which is part of a multiwire circuit.

 

Is the circuit with the problem an "Original" circuit or a newer circuit?

 

Original wiring throughout most of it, connected to new wiring into a new 200A box.... 15 amp breaker. A lot of stuff on this circuit, but I never blow the breaker even when my wife blow dries her hair.

Light was not really bright before it blew.

Having a minor setback because I accidentally blew out my multimeter by touching two hot leads while in ohms mode.

Going to get a new multimeter and try again... or maybe just call an electrician friend.

 

If original wiring, half the receptacles and lights in the house could easily be on this circuit. If your wife is using a hair dryer on 1925 vintage wiring, you are asking for trouble (which you seem to have). Ask your electrician friend, I think he'll suggest a complete rewire.

 

You are dead on with what he has already told me.

He's not available until next week, so I'll be playing with this myself until then....

Also, I guess my other question is, is there an easy way to determine which is the last good fixture or the first bad one? Or do I just take apart every fixture on the circuit? Approximately half work and half don't. However, all the fixtures on that circuit on the first floor are out while some on the second floor still work....

 

Turn the circuit breaker off in the area and see what else goes off. Normally circuits are arranged by area so if a receptacle works in the room but the next one doesn't it would be common for bot to be on the same circuit. Other than x-ray vision this is pretty much an easter egg hunt.

 

A 1925 vintage home most likely has knob & tube wiring. I know of no easy way to determine where your problem could be except to start taking apart all non-working fixtures and receptacles to look for the problem. The attic might be a good place to start looking around.

 

Often in older houses original receptacles spidered out from a light fixture rather then being daisy chained so first I'd pull any lights in the same room as the non-working receptacles. If you see a rats nest of wires then it is a good bet some receptacles are fed from the lights.

I'd look for burnt wires first. With a load like a hair dryer that would not be unexpected. If nothing obvious I'd redo all connections in the box with new wire nuts. Be very careful the insulation may flake off the wires just touching them. You may find connections that are soldered, wrapped in rubber tape, then friction tape. If the leads are long enough I'd just cut below the splice because getting them apart cab be very difficult and you don't want to damage the insulation on the wires with excessive handling.

 

If you don't already have one, get a receptacle tester. Spend the extra couple of bucks to get the one that will also test whether your GFCI protection is working the way it should. Example: GFCI Receptacle Tester.

Using that, you can determine the status of every live receptacle. Correct any faults you find as you go, and work toward the interface between the working and non-working receptacles.

Note: Knob-and-tube wiring is still code compliant, so long as the circuit isn't extended.

 

You may run into switched neutrals which was common on K&T systems.