# 200A Load Center - Max Load?



## garlandkr (Oct 23, 2011)

I have a SquareD Homeline HOM3040M200TC (30 circuits, 10 tandems, 40 total). I'd like to install a 100A sub-panel in my garage which currently has no power, I'll be running the line myself from the house which is about 150ft.

The service line is 200A, and I've counted up 260A worth of circuits in my main panel. What does this mean exactly in terms of my limitations?


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## JTGP (Oct 23, 2011)

Limitations are good.

What is the Sub-panel going to be used for?


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## garlandkr (Oct 23, 2011)

JTGP said:


> Limitations are good.
> 
> What is the Sub-panel going to be used for?



I agree, I just need to know what mine are.

It's going to be used to put some lights in the garage, a door opener and will be used with tools such as a circular saw/jigsaw/etc. Eventually I'll get a compressor but none of these should be on at the same time - save the lights.


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## JTGP (Oct 23, 2011)

200A panel is enough.

If you plan to start up your equipment (Compressor, Stove, Heater, Hot water heater,ect.) at the same time, Then you might have a problem.

Is this a new 200A panel?

What size wire feeds into the 200A panel?

Depending on the size of the Compressor, You could get away with a 60A sub-panel Main lug. 

If you are capable of clamping your feeder wire and branch circuits with a clamp meter you would be surprised on how much power is flowing.


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## speedy petey (Oct 23, 2011)

garlandkr said:


> The service line is 200A, and I've counted up 260A worth of circuits in my main panel. What does this mean exactly in terms of my limitations?


What does this mean??? 

If it means you counted up all the numbers on the breakers it means nothing. That number is worthless.


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## garlandkr (Oct 24, 2011)

speedy petey said:


> What does this mean???
> 
> If it means you counted up all the numbers on the breakers it means nothing. That number is worthless.



I had a feeling that was the case. As I was typing up the message I thought to myself, the limit of amperage is per breaker which has nothing to do with the panel itself. Thanks for the confirmation.


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## garlandkr (Oct 24, 2011)

JTGP said:


> 200A panel is enough.
> 
> If you plan to start up your equipment (Compressor, Stove, Heater, Hot water heater,ect.) at the same time, Then you might have a problem.
> 
> Is this a new 200A panel?



Yes, the panel is new.


JTGP said:


> What size wire feeds into the 200A panel?


I can't tell, its larger than a 2,2,2,4 but there are no markings on it.


JTGP said:


> Depending on the size of the Compressor, You could get away with a 60A sub-panel Main lug.


I'm going to stick with the 100A sub-panel.


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## paul52446m (Oct 24, 2011)

garlandkr said:


> I have a SquareD Homeline HOM3040M200TC (30 circuits, 10 tandems, 40 total). I'd like to install a 100A sub-panel in my garage which currently has no power, I'll be running the line myself from the house which is about 150ft.
> 
> The service line is 200A, and I've counted up 260A worth of circuits in my main panel. What does this mean exactly in terms of my limitations?



200 amps means 200 amps per leg and you have 2 legs of power, so that's 400 amps. If you have a 200 amp breaker , you can use up to 80% of that so that's 160 amps per leg. two legs would be 320 amps.
 If you added up 260 amps of breakers and you can use 80% of that , that would be 208. 320- 208 still leaves you 112. So it looks like you are in good shape. Paul


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## speedy petey (Oct 25, 2011)

paul52446m said:


> 200 amps means 200 amps per leg and you have 2 legs of power, *so that's 400 amps*. *If you have a 200 amp breaker , you can use up to 80%* of that so that's 160 amps per leg. two legs would be 320 amps.
> * If you added up 260 amps of breakers and you can use 80% of that* , that would be 208. 320- 208 still leaves you 112. So it looks like you are in good shape. Paul


I think my fellow professional electricians will agree: This WHOLE post is wrong. Please disregard all of it.



Paul, no disrespect, but you are an HVAC guy. Stick to what you know.


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## garlandkr (Oct 25, 2011)

speedy petey said:


> I think my fellow professional electricians will agree: This WHOLE post is wrong. Please disregard all of it.
> 
> 
> 
> Paul, no disrespect, but you are an HVAC guy. Stick to what you know.



so could you shed a bit of light on this subject of limitations.

as I understand it right now, the only limit is per breaker.


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## speedy petey (Oct 26, 2011)

The only true way to see what your service requirements are is a demand load calculation.
Simply adding breakers does not add load, so you can have as many sub-panels as you like. It is what's connected and running that matters.


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## BridgeMan (Oct 26, 2011)

speedy,

You sound like the kind of wire-twister I'd consider hiring.  Keep up the good work!


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## speedy petey (Oct 26, 2011)

BridgeMan said:


> speedy,
> 
> You sound like the kind of wire-twister I'd consider hiring.  Keep up the good work!


Thanks!

Set me up with some clients out there and I'll be right out.


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