Sudden light brownouts with well pump running

[maradcliff]

I just noticed this today. I was running some water when I walked in the barn. All of a sudden the barn lights went brown for a split second, like there was a very heavy draw on the power. I dont have any other heavy loads on my electrical service.

At first I thought it was either a power company surge, or the switch for my barn lights was getting bad. Minutes later, I am still running water when I walk in the garage and turn on the lights. Same thing happens. That eliminates the switch. Still the possibility the power company was having problems. However, I am wondering if this could be something with the well pump. It's a 220V submercible. Never had problems with it, but it's getting old. Yet, the water continued to flow as it should.

The control box for the well is in the garage. It has a large capacitor in it. I am wondering if that capacitor could be starting to fail, and made a split second short circuit? Is that possible?

Of course I considered a wire that could be fraying inside the well casing and shorting as the pump kicks in or out, the pump itself going bad, or maybe it has nothing to do with the well at all, and there is a wiring problem somewhere. However, this is a farm with multiple overhead triplex feeds to different buildings. Since I noted the problem in different buildings (on different overhead feeds), it seems that if it's not the well, then there is a problem in my main panel, or one of those overhead wires is momentarily arcing to a tree branch or inside itself.

Today I will check for branches and any other noticable overhead wire issues that I can see. Hopefully it was just the power company. It has not happened since. I have used water, but not running it constantly like I was when that occurred.

Anyone got any suggestions? Could a failing pump capacitor do that?

Mark

[RBM]

It's not unusual or abnormal for a slight dimming of lights to occur when large motors start. Often the starting current is around four times the running current. Any loose or deteriorated connections in that circuit would exaggerate the dimming. With an ammeter connected at the pump control box, you could determine if the pump is drawing excessive current and has a problem

[w_tom]

If lights go so dim as to be brown, then you have an electrical problem. It could be a simple loose screw or it could be something endangering the entire building.

Collect symptoms. For example 120 volt lights take power from one half of AC electric or other. Which lights dim and which lights do not? The information would then help identify which 120 volt side (both sides combine to create 240 volts) has a wiring problem.

Monitoring that voltage with a digital meter to record how low voltage drops would put a number to the problem's seriousness.

Any power lines go underground? Maybe a cable has corroded seriously. Finding it now would avoid future failures such as a burned out pump.

Any wires overhead? Maybe a compression fitting has corroded or is cracking. Finding it would again avoid other hardware damage - and get it fixed while weather is so convenient.

You did not define how large the motor is. However if capacitor is causing a brownout that excessive, then both sides of 240 volts - all

120 volt AC lights - would dim. But if any lights go brown, then you have a serious problem - no way around that fact.

[e-mail] wrote:

[Bob]

Capacitors don't gradually fail - they either open or short. I'd guess either a pump problem, wire/connection problem, or a silt buildup problem.

Bob

[maradcliff]

Yea, this was a complete brownout. The lights always dim a little when the pump kicks in and I am used to that. But this was a total brownout.

All wires are overhead in the form of triplex. As I said in original message this is two separate triplex cables (garage and barn) two separate mains and breaker boxes. The only common items are the two

200A pullout cartridge fuses directly below the meter on the main pole, which comes right off the transformer. After those fuses, every building has it's own breaker box and mains. (except small sheds being fed off the larger buildings).

So, I had a brownout in the garage and another in the barn. Each is a separate system. That only leaves the mains on the pole. Everything looks normal there.

However, I should note that I have not had another brownout since that day. The pump has run a lot and everything has been normal since. This leads me to believe that the whole problem was from the power company. These rural companies tend to have problems, but most of the time the power just goes off for a minute and comes back on. In fact I called them once because at exactly the same time each day the power would go off for a minute. They said they found a bad switching device on the lines feeding my area. I am wondering if something like this is happening again. Guess I'll watch and see if it happens again.

Thanks for the advice.

Mark

[Tony Hwang]

Hi, Be logical then. Turn off pump and see what happens.

[w_tom]

Probable that your utility created that brownout. But verify that lights do not share only one side of the 240 volts. Inspection performed either inside breaker box or by measuring between hot (black) wires of two separate light circuits. A 120 volt bulb socket should measure 240 volts between sockets from different circuit breakers. This only to confirm all lights that dimmed were on separate sides of

240 volts. Your report suggests a utility generated problem meaning this suggestion is only to expedite solutions to future (similar) problems.

If utility power is so unreliable, c> All wires are overhead in the form of triplex. As I said in original