# 100 Amp Service, is it enough?



## Leah Frances (Jan 13, 2008)

What is your question? Are you thinking about upgrading? 

There are several 'calculators' that can be found online for calculating your load requirements. Or you could turn everything on, fire up the toaster and microwave and see what happens - JUST KIDDING.


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## Speedy Petey (Feb 1, 2004)

I also wonder what your question is.

From the sound of it you are fine. 
The water heater does only use one element at a time, NEVER both. This is also only for a few minutes at a time. MOST things in a home that are high draw are only on full blast for a few minutes at a time.

Your service is 100A, 120/240V. This is 100A on EACH 120v leg, or 100A @ 240v. OR 24,000 watts of power. It is not accurate to call it 200A @ 120v, but some like to refer to it that way as an alternative.
All your calculations are quite skewed since you never mention voltage. 

The water heater is 5600W, or [email protected] 
A washer is around [email protected], or around 1400W.
A 5000btu AC is around [email protected], or around 600W.

Get the pattern?


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## jamiedolan (Sep 2, 2008)

ShaneM said:


> How can I be sure my service is enough?


You do know that if you draw too much the main breaker will open and nothing else "bad" will happen?

If that happens, then you know you either need to move a 120v load to the other leg, use less power at the same time or upgrade.


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## SD515 (Aug 17, 2008)

Leah Frances said:


> ...Or you could turn everything on, fire up the toaster and microwave and see what happens - JUST KIDDING.


 You get toasted popcorn :laughing:


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## DoctorWho (Jun 21, 2011)

I think you're okay dude, I have electric everything (except HVAC) I have dryer, range, 2 wall A/C, 2 garages, and it used to have the water heater on there too, but not at the moment, but all of these work fine for me no issues on 100A.


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## ShaneM (Jun 20, 2011)

Speedy Petey said:


> I also wonder what your question is.
> 
> From the sound of it you are fine.
> The water heater does only use one element at a time, NEVER both. This is also only for a few minutes at a time. MOST things in a home that are high draw are only on full blast for a few minutes at a time.
> ...


Sorry for not replying earlier.

I guess I couldnt see how each leg has 100 amps, when there is only (1) 100 amp breaker for the entire box. To me it would be like saying 'well this pipe can only push 100 gallons per minute. If you try to pull more than that, this emergency switch will shut off. But then you can go ahead and hook up faucets that will pull more than 100 gallons per minute in your home, and it will be fine. And the main breaker clearly says that it shuts off if you go over 100 gallons per minute.' See what I mean? This is where electricity confuses me. 

You have basically answered my question though, the service is 100 amps at 220 volts or 24000 watts (or is this what va means? 'volt amps' is basically 'watts'?) 

I was adding up amps thinking I had to total less than 100, but I really needed to work with volt amps or watts, and remember that a 10 amp microwave doesn't use 1/3 of the power of a 30 amp 220v dryer, it uses about 1/6th of the power.

Thanks for the replies, it appears I am fine with my power use. And yes I did realize that if I went over, it would just trip the main breaker, I was trying to understand how much draw was being put on the service so I knew if I was really close to max, or if I had room for expansion, etc.


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