# 200 amp panel with a 100 amp service?



## darren

Hey there

One question you should ask yourself, is there ever a chance of you putting in electric heat as your main heating source. If the answer is an absoulety no then all you need is a 100A service. If there is a chance you may consider going electric heat you should upgrade to a 200A.

My house is 1100SF have the same thing as you except my hot water tank is gas. I beleive my panel is fused at 70A and I have had no problems in the 3 yrs i have been here.

If all you need is more circuits why not keep it simple and add a subpanel for your new circuits. Will be alot cheaper then a new service.


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## jbfan

The electrician needs to do a load calclulation and see if the house needs to be upgraded. It may be that you just need a larger panel with more spaces, and not more current.
You cannot put a 200 amp main breaker panel on a 100 amp service, unless the service is protected at 100 amps.
I would not even entertain that as an idea.
How many slots are in your panel now?
Just because you need more space, does not mean you need to upgrade to 200 amps.


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## alexz

*Electrician agreed: I won't need more than 100A after the kitchen upgrade (and more)*

Thanks for replying so quickly. Very appreciated. The electrician agreed that I wont need more than 100A after my kitchen upgrades (the addition of a microwave over the range, DW, and disposer isn't going to add that much). If my gas heater ever dies, then I'll be going to electric heat pump and I understand that I will need 200A at that time. And there's a _slight_ chance that I _might _do an addition to this house in 6-8 years if real estate gets out of control and it's cheaper than buying a larger house ... very slim chance. My current fuse box is totally full - I can't add a single circuit and I need 3 more the kitchen alone and I plan on rewiring the lighting and bedrooms down the road. 

Why not use a sub-panel? I want to get off of the fuses all together. That box is old and will hurt the resale value.

One of you said:


jbfan said:


> You cannot put a 200 amp main breaker panel on a 100 amp service, unless the service is protected at 100 amps.
> I would not even entertain that as an idea.



How could you protect the service at 100 amps? Put some sort of switch/breaker/fuse between the meter and the panel? That legal? Why would you not even entertain that as an idea? If you need the circuit spaces, but don't need the amps, but want to keep your 200A option open in the future, why not? Yeah, I know I can get a 100 amp panel with 30 spaces, but why not be ready for 200A service if I MIGHT need it down the road? It'll cost me twice as much to upgrade everything to 200A. Also, spending the money on installing a 100A box would be wasted if that 200A need ever comes.


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## jbfan

Yes you would have to change the meter and add a 100 amp breaker outside.
If you are going to go thru that much trouble, you might as well upgrade the whole system then.
Right now the incoming wires are protected by the 100 amp fuses in the fusebox. If you change the fusebox to a 200 amp panel, then the wires will be protected by the 200 amp breaker, and they would be undesized.


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## alexz

*Thanks again for the prompt reply. Looks like I'm biting the bullet and ....*

.... will upgrade the entire service. But I think I found a pretty good deal!

AZ


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## dmaceld

jbfan said:


> If you change the fusebox to a 200 amp panel, then the wires will be protected by the 200 amp breaker, and they would be undesized.


Why not use a 200 amp rated panel with a 100 amp main breaker? If he can't install a 100a main in place of the 200a main, he could buy a 200a main lug panel, plug in a 100a breaker, and back feed through it. Just because the panel is rated for 200 amps doesn't mean you have to have a 200 amp main in it. Right?


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## jbfan

dmaceld said:


> Why not use a 200 amp rated panel with a 100 amp main breaker? If he can't install a 100a main in place of the 200a main, he could buy a 200a main lug panel, plug in a 100a breaker, and back feed through it. Just because the panel is rated for 200 amps doesn't mean you have to have a 200 amp main in it. Right?



If he wanted to, he could.


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## HiFi

He could do anything he wanted


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## JohnJ0906

Check your electric bill for the last year or 2 to see what the average useages are. This will give you an idea of how close to the 100 amps you are using now. You can also get this from your power company, if it is not on your bill.


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## coyote556

can you tell me how to do that load calculation using a few years of electric bills


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