Electrical demons

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Jules

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Ok had a small panel change in a short term rental. Cottage about the size of a hotel room. Bed room, wet bar and fridg, bath room. Feeder 100 amp underground from main house.

The panel needed a change out, corrosion and generally a weak/loose buss. Circuits consist of general 120 lighting, a 120 water heater and two 240V. Wall heater and hot tub.

Lights are dim and flicker and one phase of main feeder reads around 80v. This corrects itself if the 240 heater is on and returns when off. This is what was happening with the old panel and really felt the new panel wouldn't correct it but it was a start and needed replacement at any rate.

so once again heater on all is fine heater off things are wierd. Turn heater breaker off problem so I don't see it being a faulty heater.
 
Sounds like you have a bad neutral from the power company. If one phase of the feeder reads 80v I suspect the other reads 160V
 
With the voltage coming back to close to normal with 240 volt load on, I would expect a problem with one of the ungrounded conductors and not the grounded conductor. This would be something on the line side of the panel, given that the panel was just replaced.
 
By any chance, does the HO frequently shut off power to the cottage by flipping its main in the house? Since the house is okay, its not a poco problem. Id guess that breaker is bad or one of the ungrounded conductors in the feeder is damaged, causing serious voltage drop.

eta: if the lights happen to all be on one leg, it could be a bad neutral. Since you didnt mention any brighter than normal lights or burnt up appliances, the other leg probably doesnt have 160V on it. The 240V heater will not care if it gets 120/120 or 240/0, or any combination inbetween. welcome to the forum.
 
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Check voltage at the main house.
If the voltage at the feeder leaving the house to the cottage is ok , then you have a problem with the Feeder to the Cottage. Probably the original problem not the panel.
 
Jules said:
Ok had a small panel change in a short term rental. Cottage about the size of a hotel room. Bed room, wet bar and fridg, bath room. Feeder 100 amp underground from main house.

The panel needed a change out, corrosion and generally a weak/loose buss. Circuits consist of general 120 lighting, a 120 water heater and two 240V. Wall heater and hot tub.

Lights are dim and flicker and one phase of main feeder reads around 80v. This corrects itself if the 240 heater is on and returns when off. This is what was happening with the old panel and really felt the new panel wouldn't correct it but it was a start and needed replacement at any rate.

so once again heater on all is fine heater off things are wierd. Turn heater breaker off problem so I don't see it being a faulty heater.
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Description needs to be more precise!

Circuits consist of general 120 lighting, a 120 water heater and two 240V. Wall heater and hot tub. Is the 120 WH on the same or different side than the lights that flicker

Lights are dim and flicker and one phase of main feeder reads around 80v. -- as already asked, what does the other side read. This corrects itself if the 240 heater is on and returns when off assume either of the 240 heaters ? .

so once again heater on all is fine again, be specific about which heater heater off things are weird have you measured the voltage across the 240 heaters at the high side of the switch both when on and off - what are the values ? . Turn heater breaker off problem so I don't see it being a faulty heater problem Very unclear phrase - turning heter breaker off does what? - problem goes away with heater breaker off but only turning heater itself off has the problem?

You could have anything from an open high side to a shorted 240 heater. Please do a more complete attempt at trouble shooting and the answer will likely be obvious to you (if you know basic circuit theory)
 
Jules said:
Feeder 100 amp underground from main house.


Lights are dim and flicker and one phase of main feeder reads around 80v. This corrects itself if the 240 heater is on and returns when off. This is what was happening with the old panel and really felt the new panel wouldn't correct it but it was a start and needed replacement at any rate.

so once again heater on all is fine heater off things are wierd. Turn heater breaker off problem so I don't see it being a faulty heater.
Click to expand...

Sounds like one phase is backfeeding through the heater so leave the heater and all double pole breakers off. Then start trouble-shooting. Check the output of the breaker feeding the sub panel from the house (main) panel. Either you have the correct voltage there or you don't. If you do have the correct voltage at the breaker feeding the sub panel you are going to have to check out and probably replace or repair that undreground feeder cable.

If it's just a bad breaker then the homeowner is lucky so they should buy lottery tickets.
 
Bad neutral from the house. Had about the same problem in my house after rebuilding from a fire. Problem was poco. Loose neutral at the pole. Blew out 2 recessed led kits. Lucky that was all. The backfeed makes it "weird"

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I'm with Don. An open neutral will not have the symptom of a 120V load not working until a 2-pole breaker is on. I've seen it a few times, some circuits, especially lights, don't work. Then when a stove or dryer or maybe even HVAC come on the nonworking circuit starts working. It is back feeding through one leg of the 240V.

OP needs to check and see if he has 120V from each leg to neutral and also to ground. Check both from the feeder panel and the subpanel. One leg is lost somewhere, either at the feeder panel or the feeder itself somewhere along the way.
 
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