Transformer?? Sorry For The Long Post.

woodchuck2

Wondering if any of you huys have stumbled acrrossed something like this before. I got an emergency call from a friend of mine yesterday that some items in his home was either dim "brown out" or burning up. He lives in a mobile home and has a detached 3 car garage, both are powered from a 200 amp diconnect below the meter socket. The mobile home is 100 amp and the garage is 100 amp. I tested the grid side of the meter and averaged 98-108 volts on one leg and 110-132 on the other leg with no load. This did not change with garage on and home off but did change with garage off and home on, one leg would drop to 38-45 volts and the other would have 145-240 volts. I assumed there was a ground or nuetral being backfed due to a short causing one buss to pull off the other in the panel. I worked approx. 12 hours total tracing circuits, pulling everything apart looking for something miswired or a possible short. I was able to control one or several circuits from different breakers than what the circuit was hooked into. Same with switches, i was controlling some lights/recepticles from different switches although the light/rec was on a isolated circuit. I couldnt find a damn thing wrong other than some grounds missing and one rec that was miswired. I went back to the panel to check voltage again and it was normal with everything off, i tried the garage again with the home off and this time the voltage above the meter changed. I shut off the garage and told the customer to hook up his generator, i reinstalled everything in the home, put all the breakers back his panel and wired that back up, turned everything on one at a time and now have no problems in the home. The owner stated he just had the services replaced 4 yrs ago and it is all in conduit, new panel in home and garage and he stated this surge/brown-out has been ongoing for about 6 yrs. I have been to his home before and noticed the brown outs but he had a GC doing all the work at the time and now the GC " i am not bashing GC's either" wants no part of this problem. The owner has lost one TV, a new laptop, several scanners, his oven, alot of light bulbs, several clocks and his wifes treadmill. Now, i have only once seen a bad transformer on another job that caused a brown-out on one buss but no power surge and it took me several weeks to convince the grid company that the transformer was the problem. Just wondered if anyone here has seen such high power surges on one buss due to a bad transformer?

mdshunk

Classic loose neutral on the service or feeder conductors. You need to find it.

woodchuck2

I checked all of those from the disconnect in to the home, all wires in the meter socket appear to be tight when wiggled. It was pouring rain out so i wasnt going to put a tool in to check how tight. This is effecting the home and garage and the only thing those two have in common is the disconnect itself. All grounds and nuetrals are on seperate buss bars too. The grid company is coming to inspect/test today. Hopefully they find it.

woodchuck2

Just spoke with the grid company's tech, he verified that it is definetly the transformer. This doesnt seem like it would be a common problem but this is the second transformer problem that i have diagnosed in the last 4 months. Any of you other fella's having transformer problems on calls?

Magnettica

A) If you had any sort of short circuit your overcurrent protection would sense this and trip the circuit breaker. If this hasn't happened, there is no short.

Remember, there are only 3 things that can trip a circuit breaker:

1) Overload, 2) Short circuit, 3) Ground fault

B) If you have "98-108 volts on one leg and 110-132 on the other" on the "grid side" (line side of the meter), then the problem is on the power companies end, case closed. They are responsible for providing their residential customers with 120/ 240 volt single phase service.

Good luck!

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Bkessler

I would say about once or twice a year, although I cannot verify it was the transformer in each case but at least that there was a problem with the utility side of the weather head connectors.

woodchuck2

The Grid Company replaced the transformer after they themselves tested it. I tried to put a load on it when i first tested it at the disconnect and the only time the voltage varied was with the house on and is the reason why i suspected the home to be the problem. The transformer didnt show erratic voltage for both loads until the second day i was there trying to diag the problem. To be honest i dont have anything to load test the meter itself so i was using the buildings to load the meter. My bad, i will have to put together an electric heater element for a tester i guess. The home is nightmare in itself too, there have been to many people doing the wiring in it who are questionable in their skills. Another reason why i suspected the home to be a problem . I dug out 5 buried junction boxes from the walls if that says anything. Instead of using 3-wire they used several runs of 2-wire, we all know what fun that can be to diag when there is a problem. The owners have had other contractors there before to diag this problem and suspected the transformer but the grid company never found anything and stated that if they had power than there wasnt a problem.

woodchuck2

I would have to agree but after seeing this mess i had gotten into, who knows what i was going to find. The GC looked at me and said "its all yours now, good luck" . I thought for awhile that there were two circuits bonded from two different busses somewhere in a juntion box and they were backfeeding each other. I was just looking to deep into the problem and not following the obvious. Thanks for the replys.

brian11973

In regards to the question of the any one having a transformer issue: Yes

A while back, me & coworker had wired a home, about fifth or sixth home in the development, in the the country. The first home the state inspector realized that the water line was plastic. We thought he was crazy for making run ground to the meter. On this house he made us do two ground rounds (OOPS!). The excavator dug though the underground, which I fixed. Later, after the HO moved in, she had a problem. Not much, just getting shocked off of everthing metal in the house, lights acting weird & such.

Well, the builder is ranting something fierce. The splice was now under the concrete drive. Calling the electrican that fixed the wire a hack. You should have seen his face, when I told him that I fixed the wire & there was nothing wrong with it. The excavator hadn't hit the neutral anyway's.

Turns out to be a bad neutral ( hi voltage, that's what the electric co said)feeding the transformer, hit by the excavator after he hit the underground by the house. The excavator worked for & was the builders father