Smoothing electric surging from sump pumps

[Paul_NJ]

I've come to find this forum greatly helpful on just about any question as there are so many sources of expertise and experience. Oftentimes I start here because I don't know where else to ask.

My friend has two large (1/2 HP) sump pumps in her basement, which due to a high water table cycle every 30 minutes or so in the wetter months. They seldom run at the same time, but any time one or the other kick on, all the house lights, and appliances, dim momentarily. They are both 110v motors, I've checked to ensure each are on separate breakers (20A) as well as on different sides of the buss bars, and there is adequate (150A) current capacity to the house. None of the major appliances are electric. It certainly seems there should be adequate capacity although I haven't put an Amprobe on to see what the inrush current is when the pumps kick on.

Are there devices that can be installed to smooth these electrical surges? I know about surge protectors to protect electronic devices, but this would be more of a "surge smoother" I would think. Surely this must be a common problem. Any suggestions would be greatly appreciated.

[beaconlight]

I would check that the neutral has a good ground first and that all the connections are tight including the feed. Has she an old house that the breaker box and not the incoming feed from the utility was upgraded or possibly between the meter and the box. I had a somewhat similar problem that turned out to be a bad connection from Edison to the house. The tape was a different color on that side (heat discolored). I dont think you could see that today with the gell filled connectors they use but I would feel them with the back of my fingers. This way if get accidently crossed up your fingers will close pulling you off the connection.

Bill

[Ron L]

Paul. Just a quick check....... See what your wire size is and feet from motor to breaker box is. Look at the chart below for reference. You may be drawing too many amps and getting a voltage drop due to wire size. To be on the safe side, change the wire size to 12 ga. if not already (it looks like 35 feet is maximum for 14 ga. wire with one each of these motors). BTW - I like Bill's idea about not grabing the wire when you get shocked, BUT remember..... you can get electrocuted through the back of your hand as well as the front ...
Hope this helps ..............

[400lbsonacubseatspring]

If it is greatly annoying, I would go with Lurker Carl's solution, and make it a UPS system, using a marine battery, automatic battery charger, and a power inverter on each pump. That way the draw will be more constant, rather than impulsive, plus, in the event of blackout, you are protected for a while.

I raised my water heater 2ft above the floor level last year, and now I just let mine flood. At worst my coal gets wet.

[Paul_NJ]

Thanks for the responses.

Bill: can I check how well the neutral is grounded without special test equipment? It's a probably a 20 year old panel, and the ground is to a water pipe - not a driven ground as is required by today's code. So all there is besides that is the screw from the neutral bar into the grounded panel.

Ron: I'll check the wire, but one pump is about 30 feet from the panel while the other is about 6 feet. And they each dim the lights when they kick on.

Tom: But wait a minute - maybe I just don't know: is this a condition to be expected and lived with? When my air compressor or table saw with 2 HP motors kick on in the barn, all my lights don't dim like when these 1/2 HP pumps do. I've never had sump pumps before, but is this a normal behavior? If the amp surge on a pump is large enough to pull the voltage to the whole house down enough to dim all of the lights, wouldn't the breakers to those pumps trip?

I'm really confused

[Lurker Carl]

Paul, that is not normal behavior unless those pumps have a lot of debris binding the impellers. Do other large electrical loads cause the dimming as well? Your neighbor needs to get a competent electrician looking at that problem.

I have 3 of those 1/2 hp pumps in my basement and there wasn't any noticable dimming when they switched on. I converted to 12V battery power to prevent flooding when the electric goes out.

[400lbsonacubseatspring]

It's a probably a 20 year old panel, and the ground is to a water pipe - not a driven ground as is required by today's code. So all there is besides that is the screw from the neutral bar into the grounded panel.



I'm really confused

Ok....there's your problem, Paul. Drive a good ground stake, and I bet all the problems will be gone.

In my one rental property, touching the copper pipes in the basement would give you a shock in dry weather. The lights would dim when someone rang the doorbell. We drove a groundstake and ran a cable to it, and all has been well ever since.

I doubt that it's actually a voltage drop in your case, but if the ground is weak, it will only carry so much current to earth. The pumps may have difficulty drawing as much amperage as they need to in order to start.

The only time my lights dim in this house is when the big 220 AC compressor comes on. The little 220, and the 110 don't affect things at all.

[cowboy]

The guy next door to me was having some work done on the pole behind him. We were talking to linemen while they worked and they said the older taps (whatever they are) degrade (croade?) over time and changed them for him. I could not see what he did but it was on or near the transformer on the pole.

Billy

[ejhottel]

This is not that unusual a condition. When we had a reciprocating well pump with a one horsepower motor the lights not only dimmed when the motor started, but also on every upstroke of the pump. At least you could tell when the pump was running and if it was delivering water. I can still see every time my brother-in-law's 1HP pump starts (200 Amp service).
The size of the wiring from the power panel to the pumps is not the cause of voltage dips occuring on other branch circuits (lights dimming). This can only be caused by excessive voltage drop in the conductors feeding the panel. I would connect an analog voltmeter or test lamp at the input to your power panel (as close to the electric meter as you can get) and observe what occurs when the appropriate pump starts. If the voltage dips more than 2% at that point you might want to take it up with your power supplier.
Aside note, air compressors and saws seldom start under load but sump pumps do.
Also if you used 240 volt pumps there would only be half as much voltage dip.
Good Luck,

[Marion(57 Loboy)]

I don't think there's a problem here at all with surging or voltage drop. I doubt there is blockage in the impellers also.
The dimming lights effect is caused by the 110volt motor throwing the electricity out of phase. Change to 220volt and you'll never know the pumps even turn on unless you hear them.

[Paul_NJ]

I think I'm beginning to get what you guys are saying. If the 150 amp capable service voltage is being drawn down by a single 1/2HP pump enough to dim the lights, then there must be a problem with the service's capacity.

Maybe it's deteriorated service bugs like Billy mentioned restricting current flow and dropping voltage under load before the panel.

Jack, I'll connect a voltmeter where the service enters the panel and see how the voltage changes during the surges. I'll also take a closer look at the pumps and see if they are dual voltage.

Lurker, it's good to hear that your 1/2HP pumps operate without dimming the lites so at least I know it's supposed to do. Perhaps the flowrate of these pumps is too great for the discharge piping and they really backpressure, causing a large surge current. I've heard some motors can have a starting current 8 times operating current. However then I'd think that unless you had a slow blow breaker (which they don't) , the breaker would trip. Guess I ned to put an Amprobe on the pump and see what it does draw. It also makes sense to see if another large load will cause the same voltage dip.

Tom, I'll check voltage on my neutral and see if the ground is bad.

Thanks to you all. Now I have an action plan to investigate further.

Paul