Maximum breaker load in a panel

[paulhiggs]

Hi
I have a 200amp main panel and need to install a 100amp sub-panel to power my hot-tub (50amp service) and some outdoor lights and outlets.
The main panel already has breakers which when added up have a total of 585amps.

Is there any "maximum" breaker load that can be installed in the main panel?

Thanks
Paul

[HayZee518]

don't take the face value when determining loads on your main breaker amps. that is unless you are maxing out each breaker to its rated load amps in which you say is 585 amps - your main would have tripped if that was the case.
get an amprobe and turn on every device you have and see what the load is on each phase cable.
how far away is your sub panel going to be located? I need this to figure out voltage drop to be included in the calculation for the subs cable size.

[paulhiggs]

The cable run will be about 40feet to the sub-panel. My initial thought is to use 2-2-2-4 AL wire to new 100amp breaker in the main panel.

I have a GE 125amp load center that I'll probably use as the sub-panel (lug).

[HayZee518]

ok, 40 feet is no problem. voltage drop doesn't come into play until 100 feet with a drop of 3%. Is your sub panel a main lug or are you going to backfeed a 100 amp breaker?
Don't forget to include an auxillary ground bar for your equipment grounds - NOT NEUTRALS. You know your neutral cannot be bonded to the enclosure - right?

[freedgabriel]

I agree with you little. As you said voltage will drop 3% for 100feet. But really voltage will not be dropped up-to 160 to 200 feet.This will depends only how many sub panels we are using.

[HayZee518]

you rposting doesn't make sense. you can have as many subs you want within reason. and voltage drop isn't one-way measured. one wire goes out and one comes back. take the additive sum for the 100 feet.