OK, moved into 1974 mobile home two months ago, everything was working. Had an incident much like a breaker tripping, but none were. One day of flickering devices, then back to normal except none of the 220V appliances work. Stove turns on but doesn't get hot, dryer buzzes but doesn't turn on, etc. Also some weird behavior, turning the breaker to the hot water heater off made the lights in the kitchen go out, but then turning the stove on with the breaker still off made them turn on (I have junctions inside receptacles, i.e. through the "tab").

OK, so when I test the box, I have 122-124V on one side/branch, and 100-108V on the other, they fluctuate a little. All of the breakers have at least 100V between them and the ground bars. I turned the master off and measured about 2-4 ohms resistance between neutral and ground in several of the problem receptacles.

If I can figure out which wire is causing a problem at the box, I can track it down and replace whatever (pigtail, receptacle, switch, or wire if need be)... I'm just not sure where to start.

Should I pull the neutrals one by one and test them for... voltage against hot? Where should I start? Thanks in advance.

  • Hello Jason, welcome! You will get more response to your question if you clean up your wording a bit. Being a little more formal with your sentence structure may help your question be more understandable and attractive to answer. – Edwin Sep 28 '14 at 16:59
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    "None of the 220 works" sounds like a lose leg. Describe the terminations of your service drop. Are you testing using a wiggy or a volt-ohm meter? Use a wiggy. When all is back to normal, make sure turning off the HWH doesn't still kill the kitchen lights. Probably, it pulls enough juice to arc a circuit but the lights alone don't. – Mazura Sep 30 '14 at 1:52

Posting this for continuity, the results.

I actually had an open hot on one leg or branch of the breaker box, that much I knew. Here is how I found out, and what I did.

OK, so I finally got the old lady to rest long enough to unplug all the breakers (physically removed from breaker box). Still had low voltage on one breaker bar. We have a master breaker outside, near the meter.

enter image description here

It's at the top, this was a reference picture I took. Normally has a cover on it.

Ok, so I test the two at the meter... and they're both good there... so the problem is in what I find is called the "service entrance", the wiring from the meter to the breaker box. I should say now, the following repair should NOT be done by someone unfamiliar with general construction principles, and home wiring guidelines. There are laws governing how this type of repair should be done (search "service entrance" for your particular state), and not following these rules and guidelines could result in death, shock, and fines.

So my line runs about four feet underground to the trailer, lift the skirt and the rest is aboveground. According to the guidelines for Indiana, it should be 24in deep, in conduit. It was not. Not 24in deep. Not in conduit. It was 100A cable, run diagonally from ground level to about 18in down where it leaves the meter in sch. 80 PVC. And, just as I expected, I found this:

Big Problem

So, I wasn't sure about which cable to get, so I got 200A cable, thinking, I have at least 100A in breakers just for the outlets. Get cable, enough conduit to completely cover the wire, pulled out the old wire, pushed the new wire through, re-connected on both sides, reconnected all the breakers, and done. We have our hot water, stove, and dryer working again. In addition, the wiring was now up to code, the code violation being the source of the original problem. "Call an electrician" they said, when I can do a better job myself at 10% of the cost. HA! Did-It-mYself!

enter image description here

New wire, not fully connected, in brand new conduit... the lighter, L-shaped conduit under the skirt, going up into the breaker box is visible, that was the only conduit present before the repair. Gaps in the conduit were sealed with FiberFix.

I want to add a few things. 200A cable is NOT easy to work with... it is a little like bending rebar. I used my tubing cutter to strip the insulation... and a hacksaw to trim the ends. Second, this repair is not for the "home handyman", you really need to know what you are doing with electricity and wiring, 240v will travel right up the wooden handle of a shovel. Also, as I said, this is work that is supposed to be done by a licensed electrician or contractor, to "code", so unless you feel competent either fulfilling or violating said code, let someone more competent do such work. Another issue is grounding, if you mess with your service entrance cable, you ABSOLUTELY POSITIVELY need to make sure that the ground at the meter is solid. Faulty ground at your meter means faulty ground in every single outlet in your home, a shock hazard, a fire hazard, and potential death to all your electronics that rely on it.

I hope this helps someone.

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It sounds to me like you have a loose neutral wire, I would recommend turning off the main breaker followed immediately by all of the other breakers.

Then call an electrician.

While the electrician is on their way unplug all sensitive electronics.

The reason for this near paranoia like response is that there is a possibility of devices getting a full 220/240 VAC when they were only expecting 110/120 VAC.
If you started by switching off any non-paired breaker you would increase the chance for that to happen. This is because currently you probably have a near equal load on both halves of your service.

I have heard of the neutral coming disconnected when a house is being lifted off its foundation in preparation for either moving the building or replacing its foundation. ( My grandfather used to do both )
It could also happen if the connection wasn't tight enough at either end of the cable that brings power to your house, eventually coming loose due to excessive heating.

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  • Sorry, Edwin, for my unsufficient grammar... I was panicking a little that day. – Jason Brown Oct 12 '14 at 21:19
  • A little more background... we cannot afford to call an electrician, but I am an electronics technician, just more used to 1-5V and much smaller components if you know what I mean. I had planned to rewire the entire trailer... just not so soon! I am capable of doing any electrical work inside our trailer... So, what I am looking for is a way to isolate the problem circuit without tearing all of our wall panelling off. – Jason Brown Oct 12 '14 at 21:22
  • ADDITIONAL INFO: So I broke down and got a receptacle tester. Have an outlet in the living room where the vacuum cleaner works at about 50% power, so did that, and the tester (which read normal before) then read "open hot". – Jason Brown Oct 12 '14 at 21:31
  • Before we moved in, the prior owner did some electrical: new HWH installed... new branch (supposedly) for external AC compressor (not used currently). I replaced the receptacle for our dryer to make it compatible with our dryer. All "220", HWH, dryer, stove, were working normally for two months before this problem happened. IN ADDITION: I am afraid that many of our outlets/lights are "daisy chained" together, i.e. the kitchen branch goes through an outlet in the living room (through the tab on the receptacle) – Jason Brown Oct 12 '14 at 21:31
  • @JasonBrown You need to test the voltage between the one hot leg and the neutral in the main breaker box while you have an unbalanced load. If it changes by a large percentage, and the lugs where the feeder wires are attached are tight, you will need to contact your electric utility as it will be on their end. ( be very careful doing that as the feeder wires are effectively unfused ) – Brad Gilbert Oct 13 '14 at 15:57

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