Grounding or bonding issue?

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SJRibsman

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south Dakota
Hi, this concerns a trailer home. A new 100A G.E.-panel was installed. The outside trailerhome metallic paneling reads voltage. When a reading is checked on the paneling of the trailer, the voltage reading will differ at times when certain breakers are clicked on and off, the reading is checked at the ground rod. Also there is no ground wire coming from the meter can. I'm thinking that the wiring in the walls could be grounding and causing a short, but also, could the missing ground wire from the meter can cause this? By ordinace the trailer's new panel needs no bonding. Some advice was given that the panel should be bonded but, with the bonding screw tightened in to the panel, there was no difference to the situation. The main concern here is that someone could get terrible injured from this stray voltage. By the way the trailer is not in use as of yet, due to this matter! I would greatly appreciate any advice concerning this situation. SJR.
 
My first guess, bad neutral connection. The voltage will vary as different loads are applied. What are the other symptoms? some lights bright and others dim?

If the voltage is stable at the disco and not at the house panel, this is one possibility.
 
Does the service come directly to the trailer or is there a pedestal or pole mounted disconnect ahead of the trailer panel ?
 
jumper said:
I thought trailers had to have an disco, no?
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Agree, but at this point I was attempting to "troubleshoot" and thought it might have been installed without one.
Just trying to get a "picture".
 
jumper said:
Thank you. I have only worked on 3 trailers and really am not good at that code section. Never have figured out why the feeder EGC needs to be insulated.
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Nor have I, but that requirement sure comes as a surprise to most "home wring" electricians.
 
SJRibsman said:
Hi, this concerns a trailer home. A new 100A G.E.-panel was installed. ... I'm thinking that the wiring in the walls could be grounding and causing a short, but also, could the missing ground wire from the meter can cause this? .... SJR.
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I'd turn all breakers off except main outside and main inside and take the reading again...

I'll probably get run out of town for saying this, buy a AFCI breaker for yourself and install it (it seems on several circuits- and one at a time) on a circuit and test it. Please note that only the hot and neutral are monitored on AFCI's. See this pages of diagrams

If that this route is not to your tastes then get a megger and test the circuit(s) that are in question. You can megger a line and then break it apart down line to isolate the exact run that faulting. You might want to megger the SE from meter to trailer as well.

You can find some reading here on a "stitch in time-megger"

In both causes you will have to map out the circuit runs.
 
jumper said:
Thank you. I have only worked on 3 trailers and really am not good at that code section. Never have figured out why the feeder EGC needs to be insulated.
Click to expand...

Because if you used the neutral and regrounded it at the trailer, everything metal in the trailer would have a shock potential.
 
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