Portable Generator for running Sump Pump-What Size??

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Old 07-16-14, 07:06 AM
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Portable Generator for running Sump Pump-What Size??

I need a reliable way to back-up my sump pump in case the power goes out. For now I have decided to go with a portable generator but my problem is what size generator to buy. Please keep in mind I will only run the sump pump off the generator.

My sump pump is a 1/2hp in size. Every site I go to I get different results on what size I need for running watts and start up watts. The spec's on my pump are volts-115 and the amp's are 4.7.

One site says a 1/2hp pump needs 3000 watts to start and 1200 for running. Another site says 1050 running watts and 2150 starting watts. So what size generator will run my 1/2hp sump pump? Thank You for your input!
 
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Old 07-16-14, 07:11 AM
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Welcome to the forums.

As long as you're getting a generator, what's the reason for not putting things like the fridge and a couple lights and such on it?
 
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Old 07-16-14, 07:59 AM
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That is something to think about and I have thought about it. We have had 2 storms here this past month and I lucked out twice. First storm lost power for 5 hours and I had to scoop water out of the sump pump basin to prevent flooding of our finished off basement.

Where I lucked out I was able to fill a 5 gal bucket and dump it(did this 34 times)to keep ahead of the incoming water. The last storm we got 5.5 inches of rain in less than 3 hours but lucked out again cause we never lost power. The pump was running every 30 seconds. If we had lost power there was no chance of keeping up with the incoming water.

So for right now I guess my top priority is making sure that pump has power to it. Maybe it would be best just to buy a decent size generator to run the pump and a couple of other things. But do you have a size of generator that would run just the pump? One site it tells you to take your pumps volts(115)multiply that by the amps(4.7) and you come up with only 540 running watts. Then you take that number(540) and multiply that by 2.5 and you come up with 1351 starting watts.

With those figures your talking of only needing a small $150 generator as opposed to a $300+ I would need for the larger generator. So I could go both ways. Thanks for your reply.
 
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Old 07-16-14, 08:58 AM
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Once you get up into the size generator you need there is little difference in price so you might as well go bigger. It will give you extra capacity to run the fridge and maybe some lights and a TV if you're feeling luxurious. Since the generator has a governor for the most part it will burn as much fuel as needed to generate the power required. So, while a bigger generator will burn more fuel it's not as bad as it sounds and you can roughly think of fuel burn being directly related to how much power you consume.

When you mention a $150 generator I personally think you're wasting your money especially for a little 2 stroke model. Most/all of them are going to be too small to reliably start your pump. I really think you need to consider something $300+. While you may get lucky with something no name or a store brand I think you are better off with something having a name branded engine to make finding replacement parts and maintenance easier.
 
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Old 07-16-14, 09:50 AM
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Both of you bring up very good points. Your correct when you say not much difference in price with going to a generator that will power more than just the pump. Yes it would be wise to get one that could power the fridge and a couple of lights.

So thats how I'm going to go. Should I go with the heavy duty extension cord? I figure might as well. Will stick with a name brand thats for sure. Thanks for the input I do appreciate it.
 
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Old 07-16-14, 12:07 PM
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Thread moved to electrical......................
 
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Old 07-16-14, 02:33 PM
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Yes, heavy duty extension cords are a very good idea. Expensive, but a good idea. Most cheap extension cords have thin conductors. If running separate cords from the generator your pump and fridge I would look for a 14ga cord. There are heavier 12ga and 10ga cords but unless you are running cords more than 100 feet I would not go the extra expense and weight.

Many generators have one big honk'n socket. With the proper cord you could run one main, big cord into your house with an outlet box at the end. Then from there you could run individual cords to your pump, fridge and anything else you want to power.
 
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Old 07-16-14, 02:55 PM
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But if you pumps are hardwired you will need to use an inlet and transfer switch to connect the extension cord. Better to just use a transfer panel at the house and move the pumps and one or two household general purpose 120 volt circuits to the transfer panel.
 
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Old 07-16-14, 06:50 PM
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If the finished basement is that important and if your sump gets as much water and as fast as you mentioned, I think I'd also think about installing a 2nd pump so that if one fails you'll always have the 2nd pump operating. You might also think about a permanently installed standby generator with automatic transfer switch powered by natural gas.
 
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Old 07-17-14, 05:41 AM
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My relatives have a finished basement that takes on a lot of water. They have two sumps & pumps. After the second time of having to totally gut and re-do the basement after a power outage flood they bought a generator which worked fine but... they were always tied to the home. They were afraid to leave when winter storms were forecast and summer thunderstorms were a constant thread. Eventually they broke down and installed a permanent standby generator wired to the house with an automatic transfer switch. After that they were free to leave home whenever they felt like it and they've not had a flooded basement since in spite of several multi-day power outages.
 
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