How to calculate the Heat within a Panelboard 1

[giuseppe]

Hi to all.

I wonder if anyone there has a "rule of thumb" to calculate the Heat generated by a Panelboard.

I can't remember the formulas and I am presently out of books reach...!

Thanks to whomever wishes to help.

Giuseppe

 

[jraef]

2 Rules of Thumb that I was taught years ago as a designer:

1)Every thermal trip element in a circuit breaker puts off roughly 3 watts of heat per pole. Supposedly solid state trip elements don't do that any longer, but that would typically be only on big expensive 3 phase breakers anyway. I still use that rule even if the main is solid state.

2)Breaker contacts are considered to be 99.97% efficient, so look at the total connected kW load and multiply by .0003 for losses in the panel.

Combine the 2 for a total heat loss.

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[dpc]

From Cutler-Hammer Consulting Application Guide:

225A, 42 circuit Panelboard - 300 watts

(Obviously this varies with load, probably basically as the square of the current.)

 

[giuseppe]

Thanks to all for the answers.

I have now sorted the problem. It's great to be part of a forum as this, and I sincerely wish to thank you all for the time spent in answering.

All the best.

Giuseppe

 

[dogleg43]

Hoffman Engineering (the ones that make the popular NEMA style enclosures)has some free software for heat calculations. It is pretty easy to use, but it is based more for large control enclosures, panels w/computers, etc. Download it free from their website.