Breaker Tripping With Little or No Load

[Little Bill]

I had a prospective customer call me with this problem. The 15A breaker trips randomly with little load and sometimes no load.

Now before anyone says "have you tried this, have you looked at this?"
I haven't been there and only know what he told me on the phone.:happyno:

Here are the details as I got them:

Home is a mobile home

15A breaker serves one bath and master bedroom

Breaker has been changed

Someone (supposedly an electrician) has been there and didn't find anything. He did change a wall switch that he said was "buzzing" and also changed the GFCI in the bath.
He said the breaker didn't trip for about 3 weeks after the electrician was there. Then it started again. The electrician didn't have any more ideas and wouldn't come back!

HO says sometimes he comes home from work and the breaker is tripped and no one was home while he was gone.

The last time it tripped, he was home and says only two night lights were on.

GFCI never trips
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Ok I know something has to have an intermittent short for a breaker to trip with no load.
Anyone have any thoughts on this? Or anyone ever have such a problem?

I plan on megging the circuit if he wants me to come out. I just thought I might cut down on the TS time by getting some ideas on this before I go.

 

[A/A Fuel GTX]

That's a tough one. Random issues are the worst kind. Sit there all day watching your Amprobe

 

[qcroanoke]

1. Don't believe anything he tells you.
2. Check the buss where the breaker is for corrosion or burned areas. Move the breaker.

 

[GoldDigger]

I think that carefully removing ALL loads and then meggering the wiring is your best bet.
That "switch buzzing" sounds an awful lot like the switch reacting to an arcing load somewhere downstream, so that may give you a clue where to look.
And, of course, ask him about the lights flickering.

 

[augie47]

A time or two when I was trying to find that "mystery load" on a mobile home it turned out to be a receptacle with heat trace cable under the home. Seems they are often on the bath circuit. Worth taking a look.

 

[jeremysterling]

bathroom exhaust fan?

 

[hurk27]

Older Mobile homes had a GFCI in the panel that fed both bath receptacles and an outside receptacle and sometimes the heat trace receptacle would be on it.

Most newer MH's will have a GFCI receptacle in one of the baths that will feed the other baths receptacles and then they feed the outside receptacles, in these all the ones I have seen the heat trace receptacle was on it's own circuit.

I suspect that one of the outside receptacles has water getting into it which to me should be tripping the GFCI which could have been bad or they tied a underground feed to a post light and it's bad???

What is the year of the trailer? remember MH's are manufactured to HUD rules and not to the NEC to which they are up to 10 years behind the NEC. they only update CFR 24 Part 3280.800 every 10 years or longer so the 1994-2004 was based on the 1993 NEC, the 2007 is based on the 2005 NEC with amendments.

Unplug anything in the heat trace receptacle or outside receptacles, if it goes away then check these loads, look for outside receptacles with signs of rust on the terminals, signs of water getting in them.

Also if it is an older home keep in mind that someone might have changed out the GFCI in the panel to a regular breaker, if so look for outside receptacles not GFCI potected which have been required by HUD back to the late 70's also check to see if the GFCI receptacle in the bath has a set of load wires which most likely feed either another bath receptacle and or the outside receptacles, if these were put on the line side of the GFCI then the other bath (if there is one) or outside receptacles would no longer be GFCI protected, might have been done because of this problem.

The two most common problems I have found was a post light plugged into an outside receptacle or heat trace receptacle, or the heat trace went bad.

once in a great while I would find a outside receptacle that was so badly rusted it would short or just loose power.

Depending upon the MH manufacture, most would hit the heat trace first then run to one of the bath receptacle then to the outside receptacle then to the other bath if there is one, but every manufacture does it different.

 

[Little Bill]

Older Mobile homes had a GFCI in the panel that fed both bath receptacles and an outside receptacle and sometimes the heat trace receptacle would be on it.

Most newer MH's will have a GFCI receptacle in one of the baths that will feed the other baths receptacles and then they feed the outside receptacles, in these all the ones I have seen the heat trace receptacle was on it's own circuit.

I suspect that one of the outside receptacles has water getting into it which to me should be tripping the GFCI which could have been bad or they tied a underground feed to a post light and it's bad???

What is the year of the trailer? remember MH's are manufactured to HUD rules and not to the NEC to which they are up to 10 years behind the NEC. they only update CFR 24 Part 3280.800 every 10 years or longer so the 1994-2004 was based on the 1993 NEC, the 2007 is based on the 2005 NEC with amendments.

Unplug anything in the heat trace receptacle or outside receptacles, if it goes away then check these loads, look for outside receptacles with signs of rust on the terminals, signs of water getting in them.

Also if it is an older home keep in mind that someone might have changed out the GFCI in the panel to a regular breaker, if so look for outside receptacles not GFCI potected which have been required by HUD back to the late 70's also check to see if the GFCI receptacle in the bath has a set of load wires which most likely feed either another bath receptacle and or the outside receptacles, if these were put on the line side of the GFCI then the other bath (if there is one) or outside receptacles would no longer be GFCI protected, might have been done because of this problem.

The two most common problems I have found was a post light plugged into an outside receptacle or heat trace receptacle, or the heat trace went bad.

once in a great while I would find a outside receptacle that was so badly rusted it would short or just loose power.

Depending upon the MH manufacture, most would hit the heat trace first then run to one of the bath receptacle then to the outside receptacle then to the other bath if there is one, but every manufacture does it different.

He said the home was a 1995.
I asked about outside receptacles and he was sure they were on a different circuit than the tripping circuit.
Of course I will only take what he said "with a grain of salt" and look into all possible places that I can think of.

I would have thought the GFCI would have tripped if the outside receptacles were on it. Could have been bad but he said it was changed.

I don't know when I will get to go and check it out. The customer has strange work hours and hard to make a time. Plus I'm pretty busy but will try and make time as this intrigues me!