Load Center Buss Stab Capacity

[justsam]

First let me be clear, I am not an electrician, but I do have a moderate understanding of the fundamentals.

I continue to see posts regarding feeding a new or modified garage from the existing residential load center, sometimes up to 90 Amps or so.

Unless I am not understanding the limits on, for example my load center, which is a Siemens G2040B1200, the sum of the breakers per buss stab are not to exceed 110 Amps. Note this is rated breaker capacity, not actual current drawn.

Seems to me this leaves little for the existing house that may have electric kitchen appliances, AC, or other high current consumers.

What am I missing, or over thinking? Is this one of those continuous use versus non continuous or companies like Siemens playing CYA?

 

[Aceman]

First let me be clear, I am not an electrician, but I do have a moderate understanding of the fundamentals.

I continue to see posts regarding feeding a new or modified garage from the existing residential load center, sometimes up to 90 Amps or so.

Unless I am not understanding the limits on, for example my load center, which is a Siemens G2040B1200, the sum of the breakers per buss stab are not to exceed 110 Amps. Note this is rated breaker capacity, not actual current drawn.

Seems to me this leaves little for the existing house that may have electric kitchen appliances, AC, or other high current consumers.

What am I missing, or over thinking?

So put a 20 across from the 90......

 

[Norcal]

So put a 20 across from the 90......

About as simple of a solution as you can get.

 

[justsam]

OK, I have to admit at first I thought your replys were a bit flippant, but realized that Aceman had used the word ACROSS.

I was thinking of the entire stab buss, in a vertical array, of every other breaker position. I now realize that it indeed refers to only the sum of two breakers, across from one anotherr, which indeed are on the same stab.

Had I thought about it long enough, with my initial way of thinking you could not even have six 20 amp breakers on the 110 Amp vertical stab buss.

Embarrassed myself a little, but did learn something, Thank you!