Fluctuating voltage

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Oakey

Oakey

Senior Member
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New Jersey
Hello ..I am new to the forums so I dont know if this has ever been discussed before. I have a customer who claims that there electric bills are outrageous..over $550 a month.It is a 1980's house with a 200 amp main. Checked for leakage in the ground, shut off individual breakers and accounted, one at a time, for all rhe power being used and saw no excess usage. They have electric dryer and of course central A/C. Water heater is on the hot water boiler but no well water, so no pump.However when I checked the electric stove (which is 40 amps) I noticed the amperage would fluctuate between 12 amps and 22 amps on each leg every 15 seconds or so. It is wired with 8/2 SEU so Ill probably change it to 8/3 RX. Any ideas why it would do this? Thx for any ideas
 
Re: Fluctuating voltage

With it drawing 22 amp the range should be warm to touch I would think.
Unplug the oven (OPEN THE BREAKER FIRST)
check current readings on cable feeding the range receptacle.
IF zero then problem is in range.
What do you know about range wiring?
 
Re: Fluctuating voltage

Like George said.

The range eye thermostat has a built in heater which controls the temperature of the eye it was probably cycling off and on to maintain a low temperature if you didn't have it turned all the way to high.

I would check else where.

How about the emergency strip heat, I would rule that out now before it gets to cold.Could be it is cutting in and the AC tries to compensate. :)
 
Re: Fluctuating voltage

Hi, I am assuming that you had used an amprobe on the 8/2 wire feeding the stove. It all depends on where you were reading the current. If you were reading the current on the 8/2 hot legs to the stove, then it can only be the stove that is causing this to happen. It sounds to me that the oven part of the stove is kicking on and off for some reason. It could be a bad oven control or in the case of a digital control, it could be a bad circuit board or something. You would not see the oven heating element get red if it is cycling that fast. Something is wrong in the stove itself. You say the current cycles from 12 amps to 22 amps. What elements on the stove are "ON" when you are making this test? If every 15 seconds the current is going to 22 amps, I think in the course of a month that could easily run up a high electrical bill.
 
Re: Fluctuating voltage

Turn on a known load, something like a water heater which is known wattage. turn off everything else and see if the meter is reading close to the power being used. Resistive load is easier to calculate because power factor is 1 so VA = watts.

You can also turn on more loads, and use your meter to measure amperage on the lines to make it go a little faster. It may take a while, but you can make a pretty good check on the meter.
 
Re: Fluctuating voltage

Thx for all the helpful hints! To give some more info..I turned on one element on the stove and also the oven to give it some load. They were both calling and had not made temp yet as I went straight to the panel to check amperage. I used a fluke amprobe by the panel to test all these things. I did check everything else in the house the stove just happened to be last... it fluctuated for the whole ten minutes I watched the amprobe and I was wondering if this is normal for resistive heat but by the answers here its not. I will print out and check all of the suggestions made here to see if I get any answers to this. Unfortunately I know nothing of internal stove repair.
 
Re: Fluctuating voltage

Forget the stove. It's not on enough to drive up the bill. Sounds normal to me anyway. The range top elements do not have a thermostat, so they are always on a sort of % on/off setting even when just turned on. The bottom oven element also cycles once the temperature gets up.

I have heard of water heater elements getting a hole in them so they heat very little, and consequently use a lot of power. The ones I have known for sure that happened with have been in a steam table/vat heater setup with several elements in parallel. I think I could see how it might happen in a standard dual element electric water heater.

You may also want to recommend the homeowner has an AC company check the condition of the unit, not so much for current draw, as for performance. Ours will get choked with lint in the evaporator every few years even with us regularly changing filters. Effeciency goes down severely, the unit spends more time running and if the house still stays cool, no-one really notices except for the bill.

Looking forward to the fall weather! time to check the evaporator coil before winter heating season.

Jim
 
Re: Fluctuating voltage

Ask the POCO to check the meter. Sometimes the POCO charges on estimate basis without recording the meter.
 
I dont mean to bring up an old thread but just 2 days ago we solved the mystery of the big power bill. My customer noticed his outside receptacle cover was open..one he never uses. I loaned him my video camera and what do you know...Mr nice neighbor that he is great friends with was plugging in his extension cord, running into his garage where he operates a wood shop building furniture and sucked up power till about 4:00.
And to think we swam in this guys pool and drank his beer July 4th. What a jerk!
 
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