Troubleshooting

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ken44

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Austin, TX
I just got back from trying to troubleshoot a problem that a customer was having at the electrical service of a recently purchased repossessed mobile home, they called me because lamps started blowing out when they went to turn on the switches. When I arrived I turned on power at the meter (200 amp service with the grounded conductor being grounded by means of a split bolt to the wire that was going up the pole to the transformer) and checked line and load voltages, everything seemed to be in order at the pole, however when I went to the panel board at the mobile home, I found 230 volts from "A" phase to neutral explaining the burning lamp problem, at this point I had not turned the 200 amp breaker in the mobile home panel on yet, with it still off, I went outside to see the ground rod and wire, the person who did the work had put a plumbing fitting in line with the electrical PVC that had a hole in it and they ran the solid ground wire and the A/C wire out of that hole, then the ground wire was connected to a ground rod sticking 16" out of the ground and clamped by means of a rubber hose clamp! I touched the rod and got a shock, there was 60 volts from the ground rod to the earth, I keep getting a continuity reading of zero ohms between one ground bar and the "A" phase wire and when I go to the other side of the ground bar to "A" phase with my ohmmeter, I get around 400 ohms. A lot of weird stuff going on, can anyone help? The panel in the mobile home is a 200-amp siemens panel. The service at the pole is a 200 amp GE and was done poorly by the utility company, they used 20' of EMT going up the pole, there are no screws in the meter box at all and only one screw in the GE can.
 
Re: Troubleshooting

What ever you do, tell who ever that the power can not be turned on until this is resolved!

It sounds like at the service there is no connection between the grounding conductor and the grounded conductor, or a grounding conductor is not ran with the feeders to the trailer panel and since the trailer panel is require to have the grounding separated from the grounded conductors then there has to be a bond between them and the neutral has a bad connection somewhere maybe under ground as in a splice. this will liven up all the grounding on or in this trailer and is one of the main reasons the NEC and the HUD code 3280 does not allow this. There must be 4-wires that come in from the service or if there is a disconnect then it is allowed to have a 3-wire feeder between the service and this disconnect but it must be a 4-wire conductors from this disconnect to the panel in the trailer and only at the disconnect with a 3-wire feed must the grounding and grounded conductors be bonded together. as for grounding electrodes go one is required at each or all of these three points.
one ate the main service one at the disconnect ( because it is the bonding point of the neutral to the grounding conductor (3-wire) and one at the trailer. This is a must and has to be checked out at all points. But the first thing I would check for is see if there is a disconnect under the trailer where the neutral might have a bad connection. If the main service is father than 30' from the trailer then it is required to have a disconnect at the trailer but here we are required to keep it no closer than 24" from the trailer. This is in case there is a fire the fireman don't have to get to close to turn off the power. read article 550 in the NEC for more requirements for trailers. and if you can go to the HUD web site at www.hud.com and look up the CFR24 3280 documents for HUD rules and codes on manufactured homes. As HUD supersedes the NEC in all states and local jurisdictions.
 
Re: Troubleshooting

Sounds like phases are miss marked.Would remove them from both ends and check.This could be a result of an unhappy previous owner getting even.Make sure that white tape is on same wire on both ends
 
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