Assuming it means what the panel is bussed at. Paperwork has fields for RATED POWER and RATED AMPS. Rated amps would be the same as the main breaker, so 600a for this panel. One line diagram says system: 480Y/277 VAC 3PH 4W 60 HZ 42,000 AMPS SYMS. SCCR.
Does that mean the rated power is 42k amps?
2007-04-08 10:56:50 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
42,000 amps (also referred to as 42 kA) is the fault duty interrupting rating. The panel (and its main breaker) has been tested to successfully interrupt a fault of 42,000 amps.
There are various fault duty ratings available on the market, and the prices goes up with the rating.
According to the electrical code, you can load a panel to 80% of the 600 amp rating. .80 x 600 = 480 amps.
2007-04-08 11:44:07 · answer #1 · answered by Thomas C 6 · 0⤊ 0⤋
Review Sections 110.9 and 110.10 of the National Electrical Code.
SCCR and AIC ratings are not the same.
The short circuit analysis of the electrical system is first determined by calculating the estimate available fault current at the secondary of the utility transformer. Once this is known, a simple point-to-point calculation can be used to determine the needed withstand rating of all equipment at the line side terminals.
The SCCR rating is a function of the system impedance. The AIC rating is the value of current the overcurrent devices can interrupt without failing.
2007-04-09 01:00:55 · answer #2 · answered by Bryan H 3 · 1⤊ 0⤋