While my dad is building our house he has our new well pump at the site plugged into 4 extension cords until the electrical panel is installed. The pump is serving our current house about 50yds from the new house site.

Safety concerns aside (he is impossible to reason with sometimes), could this be causing a significant increase in power consumption over being plugged or wired directly? Our power bill is wildly expensive ($800/mo) for a small (800sf) house with a new energy rated fridge, new 7cf chest freezer that is rarely opened, washer/dryer and otherwise normal small appliances like coffee maker, tv, Xbox, small fan, etc.

The only other thing I can think of is maybe the the old water heater is drawing a lot of energy? I don’t know how to test and figure out where the “suck” is coming from. I just feel like it shouldn’t cost this much to power this modest house!

Appreciate any constructive thoughts. If I’m missing important information I’m sorry, I admit being pretty ignorant about power consumption but I do want to learn. I have to figure out how to get this bill down.

  • 20
    Rather than giving consumption in money terms, give it in kWh (per month). Electricity prices vary massively depending on location, apparently even within the USA (country assumed based more on imperial units than $). $800 is a lot, but knowing the actual consumption may help pin it down.
    – Chris H
    Commented Sep 1, 2023 at 9:50
  • 4
    Not related to consumption exactly, but for the health of the pump, the extension cords should be 12AWG. This will reduce voltage drop, compared to a smaller cord. Commented Sep 1, 2023 at 11:14
  • 3
    Is that 4 extension cords at 25' each or 4 at 150' each? You say the pump is 150 yards (150') from the new house, but that doesn't tell us where it's plugged in - often times, there's no power at a new construction site. Also, if they're light duty, indoor extension cords then you're very likely experiencing voltage drop as has been noted elsewhere, and this is causing issues for the pump. You may well end up having to replace the pump in addition to paying extra high electric bills.
    – FreeMan
    Commented Sep 1, 2023 at 12:05
  • 2
    How much (roughly) is $800 in kWh in the US ?
    – fraxinus
    Commented Sep 1, 2023 at 17:05
  • 2
    @fraxinus, figure $0.15/kWh, give or take. That's an obscene power bill. Something's very wrong.
    – isherwood
    Commented Sep 1, 2023 at 20:37

6 Answers 6


Go to Walmart and get Kill-A-Watt. It's a device you plug into a socket and plug the extension cord into it. Then you can see the power usage (in Watts) and also the daily usage if you leave it plugged in for whole day.

You can check the pump, and the heater.

But check what plugs do they use, so they actually fit into your kill-a-watt.

My prime suspect is a heater, they draw ridiculous amount of energy.

Theoretically, if you use very long cable, the pump may work slower due to voltage drop and you will use more electricity due to losses in the cable. But it is impossible to tell without measuring the voltage drop and knowing what kind of pump it is.

Connecting several extension cords is not recommended. For peace of mind, check that all the connections are not exposed to rain, and cover them if necessary.

  • I second this, I own a Kill-A-Watt device and it is extremely handy at tracking down high energy consuming devices! You can get daily, monthly and year power cost estimates after entering in your kWh price listed on your bill from the power company.
    – matt.
    Commented Sep 1, 2023 at 13:51
  • 1
    Also your local library may have one you can borrow for free. Mine does
    – nuggethead
    Commented Sep 2, 2023 at 2:08
  • @nuggethead Kill-a-watt is very useful and cheap enough that there is no excuse to not own one. Might be cheaper than gas you use to get to shop.
    – Thomas
    Commented Sep 5, 2023 at 9:03

I assume you US guys can observe your energy meter with live consumption data? Switch off each breaker in the house while someone observes the meter. That could help you to narrow it down.

A water heater ought to be the prime suspect. The well pump itself could have an always-on defect, perhaps due to undervoltage from the long extension cords.

Those extension cables would make it easy for you to measure the power: Apply one of those power meter plugs.


tl;dr: No, the extension cords are not causing your bill to be so high. However, do not do this because it is dangerous.

I will make a great many assumptions, including:

  • The average US rate per kWh is about 25 cents, so with a little bit of line charge and service fee, your $800/mo. bill is about 3 MWh (3,000 kWh).
  • The extension cords that you're running are 16 ga, single-phase grounded. This is normal for an ordinary orange outdoor extension cord.
  • Your well pump runs about 10 A, which seems like it would be approximately the ballpark for normal use for an 800 sqft. house.
  • I'm rounding because I've already done the math in my head and I know that a few percent plus or minus won't make a difference in the bottom line.

Given other normal assumptions, at about 0.1 ohms per conductor, so 0.2 ohms, for 150 feet (50 yards, as quoted), your voltage drop is 1 volt across these extension cords. That voltage drop at 10 A generates 10 W of lost power.

Let's assume this all goes to heat, which is reasonable for an order-of-magnitude calculation. That's about as much heat as a large LED light, spread out over 150 feet. At constant loading, your extension wouldn't be particularly warm to the touch. Summer ambient heat would cause a significantly larger temperature shift.

Also with this assumption, you are losing 720 Wh (0.720 kWh) per month to extension cord line loss. At 25 cents per kWh, that's about 18 cents a month. You're not even close to this being the cause of your astronomical energy bill, not by several orders of magnitude.

On the other hand, daisy-chaining extension cords is dubious at best and possibly dangerous. When selecting the correct extension cord, which are UL-rated by length and maximum current draw, one must select by total length, which would be the combined length of the cords in this case. That is, each cord must individually be of the correct ampacity for the entire length.

For a 10 A continuous load, let's call it 15 A because there are some other related factors, 16 ga is too small. 14 ga may be passable for a single cord, but you may have connector insertion losses from multiple cables. I'm not promising anything, but if it's a 12 ga extension cord, under perfect conditions, the cord rating is better than the nominal steady-state draw. This would mean that of three 50 ft cords spanning 150 feet, all three would have to be 12 ga.

If something goes wrong and the rotor locks, the well motor may draw very much more current. This could be to the order of 50 A or 100 A. Your extension cords would heat very quickly and things could go horribly wrong if you don't stop the pump and clear whatever is jamming it, quickly.

There are other hazards but the majority of ampacity calculations are centered around generation of parasitic heat, so this would cover some of the more-feared cases.

As a side note, your bill is high. I don't disagree with other posters' suggestions to check the heater and such, but you're still higher than ordinary. Check for some of these possibilities:

  • Your rate is somehow listed as higher than what it should be or your power company made a billing mistake.
  • Is someone else hijacking your power? This could be checked by shutting off your main breaker at night and seeing if anyone else's lights go off. Also check in the vicinity of your meter for wires that look out of place.
  • Are you running something that uses abnormal amounts of power? Are you mining Bitcoin? Do you run a growing operation? Do you regularly charge one or more Teslas?
  • 1
    +1 for the note at the end. The power cords, and for that matter the pump, are clearly not the right tree to be barking up, given the sheer amount of power we are talking about. I can imagine the pump drawing 50A if it jams, but it would have to have been drawing that continuously for a month. OP would surely have noticed that because (a) they would have no water, (b) the pump would be on fire. Commented Sep 2, 2023 at 16:57
  • > If something goes wrong and the rotor locks, the well motor may draw very much more current. This could be to the order of 50 A or 100 A. Your extension cords would heat very quickly and things could go horribly wrong if you don't stop the pump and clear whatever is jamming it, quickly. Would such a load not trip a breaker quite quickly?
    – Bob
    Commented Sep 3, 2023 at 13:30
  • @Bob hopefully yes but not definitely. Given this "average" breaker trip curve, if someone installed a 30 A breaker and the locked current for this particular pump is 50 A, trip times could be in minutes. Commented Sep 5, 2023 at 11:34

You mention a water heater. That could use a lot of power, but you'd expect to either notice steam escaping (possibly followed by smoke and flames) or lots of hot water flowing.

A bad leak on the output side of a water heater into somewhere it could drain away (a crawlspace on dirt, for example) would be just about possible. Even that should be noticeable by weak hot water flow when you do use it and warmth above where the leak is.

I'd still turn off its breaker as the first one when you test them, followed by any for space heating, air conditioning, and cooking.


Long-run extension cords drop efficiency by a few percent. In extreme cases 15%. You are saying you guys are using 2x to 4x more power than you ought to be.

I can think of two things that would use that much power that would not be immediately obvious; 1) someone is stealing power from you, 2) there is a current leak to ground.

Obvious things would be an electric heater running often or a malfunctioning pump or AC unit that was running very often. The pump would probably need to run nearly 24/7.

... Do you have electric cars?


There are two things to do to try and reduce your power bill.

  1. Switch everything off for 10 mins, and check if you power meter is till ticking over. If it is then find what you have missed. If you havent missed anything then someone else is using your power or you have a fault somewhere (unlikely, but possible).

  2. Get a pluggable energy meter (there are many out there that will measure amps or kilowatts). Plug it for a day behind each appliance and then total up the consumption.

  • This isn’t adding anything new. Both suggestions were already posted days before this answer.
    – nobody
    Commented Sep 3, 2023 at 16:45

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