Can a 800 Amp Breaker feed two panels?

[pjayakrish]

[pre]I have a project requiring 480 Volt feeds for a 500 Amp VFD panel and a 220 Amp heater panel both used for the same furnace. Both the panels have fused disconnect switches. Can I feed them from one 800 Amp breaker (in one of the 480 V sub stations) without the need to install another local panel with separate disconnect or breakers to sub feed each panel separately? If yes, should I size both the cables for the service breaker rating (800 Amps here)?

 

[waross]

That depends a lot on your local codes.

Bill
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"Why not the best?"
Jimmy Carter

 

[pjayakrish]

Is there a NEC code section that addresses this question? I could not find anything specific in 2014 version. Thanks

 

[resqcapt19]

The conductors between the 800 amp breaker and the two panels would be "tap conductors" if they are not rated at 800 amps. The rules for the overcurrent protection of tap conductors are found in 240.21(B). The two panels would require a main or line side OCPD with a rating that does not exceed the rating of the panels.

If both sets of conductors are full size there is no code issue other than having lugs at the 800 amp breaker suitable for the connection of two sets of conductors. These panels would have to either be rated at 800 amps or have a main or line side OCPD with a rating that does not exceed the rating of the panels.