Troubleshooting tips and tricks...

Status
Not open for further replies.
S

sw_ross

Senior Member
Location
NoDak
Looking for people's favorite tricks and tips for troubleshooting a circuit where the breaker consistently trips.

It's a receptacle circuit that has 3 receps. As soon as you try to plug a load in (various loads were used) the prong tips arc'd to the Recep contacts and the breaker tripped. Voltage checked out good L-N & L-G. The original install was about 6 years ago. Everything is NMB and plastic boxes. Standard breakers.

I took the boxes apart, nothing looked amiss. I changed out the Recep that initially arc'd thinking there was an issue with it but same thing happened with new. I remade up the pigtails in the boxes but nothing looked bad.

Additional test was to plug in lamp (which works fine in other receps) while the breaker was off, when I turned the breaker on it instantly trips and won't hold.

Checked the panel out for visible issues with terminations. Nothing visible. Might try and move Line to a different breaker to rule out breaker issue.

Looking for suggestions of tests to play around with tomorrow.
Thanks!
 
Tip: Wire a high-wattage incandescent bulb in-line at the breaker as a combo current-limiter (so the breaker can stay on) and status indicator (as you find the problem) using either a rubber socket or a receptacle with a lamp plugged into it.

Ground wire close to hot terminal of receptacle? What receptacles are you talking about? Kitchen, bath, or outdoors? As Hal suggests, it could be a mis-wired GFCI.
 
Does it happen on all three of the receps or only one? (which one in the line?)
Try disconnecting any down-stream recep's, does it still trip?
If you remove the first recep and hard-wire a lamp towards the breaker, does it trip?

Basically, divide and conquer.
 
LarryFine said:
Tip: Wire a high-wattage incandescent bulb in-line at the breaker as a combo current-limiter (so the breaker can stay on) and status indicator (as you find the problem) using either a rubber socket or a receptacle with a lamp plugged into it.

Ground wire close to hot terminal of receptacle? What receptacles are you talking about? Kitchen, bath, or outdoors? As Hal suggests, it could be a mis-wired GFCI.
Click to expand...

funny, I was just thinking about the days of past when you could screw in a light bulb into a fuse base to "de-illuminate" the problem.. lucky for me I have a box of incandescents laying around. anyhow... sounds like the red flag is when the return is completed with a load... I bet you could make the circuit trip by pressing on the recept with the handle end of your hammer- ie, bad make up. as in the nick on the white is 1mm from the over stripped hot... ?
 
This is actually a hotel room! Recep circuit dedicated to that room. No gfci Recep or breaker involved.

I was able to identify which one was the HR. I plan to use the high wattage bulb with a rubber socket today. I'm kinda wondering about the NMB being nicked when stripped. I'll look more at that today.

The story was that the tripping was intermittent but I couldn't get it to hold at all. Maybe a nick in the NMB as it comes into box has the conductors so close it doesn't trip until there's a load?

No new construction or new wall hanging's from what they told me.

I was actually surprised to find NMB being used. I would've expected EMT and/or MC. Is NMB used a lot on hotels? This one just has 2 stories, I know there's a height limit for use of NMB.

Anyways, thanks for the advice.
 
If possible, find the first receptacle on the line. Disconnect the other receptacles and see if the breaker trips under the circumstances you described. If so then there is a problem between that location and the breaker panel. Otherwise, if it doesn't trip the breaker add one receptacle to the circuit at a time and see if if anything changes. Seeing as how there are only 3 receptacles you won't have far to go. On more extensive circuits I usually try to split the circuit in half and work backwards or forwards to find the problem.
 
goldstar said:
If possible, find the first receptacle on the line. Disconnect the other receptacles and see if the breaker trips under the circumstances you described. If so then there is a problem between that location and the breaker panel. Otherwise, if it doesn't trip the breaker add one receptacle to the circuit at a time and see if if anything changes. Seeing as how there are only 3 receptacles you won't have far to go. On more extensive circuits I usually try to split the circuit in half and work backwards or forwards to find the problem.
Click to expand...

That was the last thing I did before running out of time yesterday. Found which was the HR, hooked a Recep up to it only. It still tripped. I need to get a better look at that NMB coming into the box for stripping issues. Insulators foamed up the openings so much I'll have to dig my way through the foam to find the NMB.

Hopefully it's not an issue somewhere in the wall with stapling that has gotten worse with age. This wing of hotel is 6 years old. They said no issues until now with this circuit.
 
sw_ross said:
Looking for people's favorite tricks and tips for troubleshooting a circuit where the breaker consistently trips.

It's a receptacle circuit that has 3 receps. As soon as you try to plug a load in (various loads were used) the prong tips arc'd to the Recep contacts and the breaker tripped. Voltage checked out good L-N & L-G. The original install was about 6 years ago. Everything is NMB and plastic boxes. Standard breakers.

I took the boxes apart, nothing looked amiss. I changed out the Recep that initially arc'd thinking there was an issue with it but same thing happened with new. I remade up the pigtails in the boxes but nothing looked bad.

Additional test was to plug in lamp (which works fine in other receps) while the breaker was off, when I turned the breaker on it instantly trips and won't hold.

Checked the panel out for visible issues with terminations. Nothing visible. Might try and move Line to a different breaker to rule out breaker issue.

Looking for suggestions of tests to play around with tomorrow.
Thanks!
Click to expand...
Thought about jus fitting a new breaker?
 
Besoeker said:
Thought about jus fitting a new breaker?
Click to expand...

That’s also on my list of possibilities. If I don’t find issues at the recep location I’ll try changing out the breaker. I’m thinking the odds of breaker failure is less than issue in recep box. But it is possible if the issue was intermittent and then full on maybe the breaker got tired of tripping... That sometimes happens to me as the day goes on, especially fridays!?
 
sw_ross said:
It's a receptacle circuit that has 3 receps. As soon as you try to plug a load in (various loads were used) the prong tips arc'd to the Recep contacts and the breaker tripped.
Click to expand...

sw_ross said:
Maybe a nick in the NMB as it comes into box has the conductors so close it doesn't trip until there's a load?
Click to expand...

If a breaker trips it's normally either a short circuit or bad breaker.

Did you check resistance between hot and ground and hot and neutral. You will probably find the circuit is shorted. Now you can check out the circuit with the power off using your
meter to determine when the circuit is shorted or not by wiggling the wires around.

Could even be the staple right before the box. Hotel and Motel wiring is notoriously bad.
 
K8MHZ said:
I wouldn't without checking the circuit with an ohmmeter. I don't think that's been done yet, has it?
Click to expand...

It certainly doesn't sound like and that's not a trick it's just standard troubleshooting procedure.

If you have enough of a short to trip a breaker you can normally see it with an ohmmeter.
 
sw_ross said:
That’s also on my list of possibilities. If I don’t find issues at the recep location I’ll try changing out the breaker. I’m thinking the odds of breaker failure is less than issue in recep box. But it is possible if the issue was intermittent and then full on maybe the breaker got tired of tripping... That sometimes happens to me as the day goes on, especially fridays!?
Click to expand...
Surely it would be a cheap, cheap, and simple thing to do? I think it's the first thing I would have tried given the reported symptoms,
 
Besoeker said:
Surely it would be a cheap, cheap, and simple thing to do? I think it's the first thing I would have tried given the reported symptoms,
Click to expand...

It will take you longer to get the cover off a panel than it will take to see if you have a short with an ohmmeter . Out in the real world you will find a dozen short circuits for every bad breaker as to the cause of tripping.
 
growler said:
It will take you longer to get the cover off a panel than it will take to see if you have a short with an ohmmeter . Out in the real world you will find a dozen short circuits for every bad breaker as to the cause of tripping.
Click to expand...
If the breaker trips only when an appliance is plugged in.............
Voltage checked out good L-N & L-G.
Click to expand...
 
If the breaker trips only when an appliance is plugged in.............
Click to expand...

Then I can't see it being a wiring problem especially when the same thing happens regardless of what receptacle you use. The first thing I would do is replace the breaker.

-Hal
 
Update-

Yes I did ohm out the conductors. That was the first thing I did after checking voltage.

Turns out it was the microwave that was tripping the breaker each time I tried to plug it in. I thought for sure I had also tried the lamp as well but I guess I was mistaken.

Yesterday When the maintenance guy showed me the issue my first thought was an issue with the micro but I got distracted because I thought I tried the lamp and had the same issue. Should've gone with my gut and double checked things better yesterday but was short on time.

First thing I did today was try the micro in 2 other circuits with the same results.

Live and learn...
 
Status
Not open for further replies.
Top