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Solve This Service Call

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480sparky

480sparky

Senior Member
Location
Iowegia
Little Bill said:
Need more info. Did the 3-way switch, or wiring there of, have anything to do with the problem?
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No. It was just the HO showing off his new fancy tester that he thought the red light meant that's where the problem is. The red light simply indicated the presence of voltage.

Little Bill said:
I would find out what was on the circuit that trips the main when the breaker for that circuit is turned on.
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It was marked "Kitchen hall bath basement lights"

Little Bill said:
Unless the main isn't breaking contact on both legs, how is "half the house" going off?
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"Half the house" going off is simply the HO being confused.
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
480sparky said:
So how would you diagnosis this?
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Use solenoid tester to determine which black is the feed in, use that to identify the rest of the blacks.

Remember, I said that when we were under the impression that the 3-way is what turned off half of the house.
 
Little Bill

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
LarryFine said:
Use solenoid tester to determine which black is the feed in, use that to identify the rest of the blacks.

Remember, I said that when we were under the impression that the 3-way is what turned off half of the house.
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OP said the 3-way (and assoc. wiring) didn't have anything to do with the problem.
 
S

SSDriver

Senior Member
Location
California
Occupation
Electrician
I'm going with open neutral on a MWBC that was not put on a proper 2 pole breaker or did not use handle ties. I would look at all devices that were listed on breaker 14 and see if any are newer smart device switches that require a neutral and see if the HO made a crummy splice to the neutral and it pulled out. I would also ask the customer what doesn't work when breaker 14 is off and what doesn't work when you turn breaker 14 on.

EDIT: if its a newer house. It probably has romex. If it is a MWBC it might be on 3 wire romex and I can see what other circuit is using the same neutral by removing the cover on the panel. If so shut off that breaker and open up all boxes related to what doesn't currently have power.
 
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S

sw_ross

Senior Member
Location
NoDak
I would turn off all other single pole breakers, the see if turning on #14 still trips the main.
If the main does hold I would then start turning on the single pole breakers until you find the one that causes the main to trip again.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Occupation
EC
NCVT indication near a wall switch often means the yoke isn't connected to the EGC and is capacitively coupling the yoke to indicate it is "hot".

Used to have inspectors wave them past every switch when doing a final inspection, any of them having indication means we will be taking the plate off and checking grounding connections. Only had one time where a luminaire tested this way yet was bonded well, no idea why it set his tester off.
 
480sparky

480sparky

Senior Member
Location
Iowegia
sw_ross said:
I would turn off all other single pole breakers, the see if turning on #14 still trips the main.
If the main does hold I would then start turning on the single pole breakers until you find the one that causes the main to trip again.
Click to expand...

If turning on the 15a breaker in space 14 trips the main, I assumed there was a dead short between that and a circuit that was on the other leg in the panel. So I got the Fluke out and clipped one lead to the neutral bar and the other onto the terminal of the turned-off breaker. It read 122.4 volts.
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
480sparky said:
If turning on the 15a breaker in space 14 trips the main, I assumed there was a dead short between that and a circuit that was on the other leg in the panel. So I got the Fluke out and clipped one lead to the neutral bar and the other onto the terminal of the turned-off breaker. It read 122.4 volts.
Click to expand...
What about to the can? I would say can not bonded, circuit 14 is shorted to can by the connector or other means, grounds are on separate ground bar bonded to the can, miswire some where (probably by the HO trying to make it work)
Connecting circuit #14 to a opposite leg breaker. (Assuming the panel is service equipment)
 
480sparky

480sparky

Senior Member
Location
Iowegia
hillbilly1 said:
What about to the can? I would say can not bonded, circuit 14 is shorted to can by the connector or other means, grounds are on separate ground bar bonded to the can, miswire some where (probably by the HO trying to make it work)
Connecting circuit #14 to a opposite leg breaker. (Assuming the panel is service equipment)
Click to expand...

The fact that everything works, even with one breaker turned off, is a big clue.
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Time to insert a high-wattage bulb in series with the offending breaker to act as a combination current-limiter and indicator.
 
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