Is it OK for a panel to fed with a breaker smaller than the panel size

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crose

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Let me give you some context. I work for a satellite ground station manufacturer. We install very large full motion antenna systems. Our systems are supplied with a 100A breaker box, however depending on the configured options we may only require 25-30amps per leg (3-phase 208).

Our customers typically build the site to support the power requirements of their particular configuration. So if only 30 amps are required for the system as configured, the site contractor will install a dedicated 30A 3-phase breaker just for our antenna and a 10AWG feeder line or our 100A breaker box. Is this OK and compliant with NEC?
 
crose said:
Is this OK and compliant with NEC?
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Yes.

408.36

2008

...a panelboard shall be protected by an overcurrent protective device having a rating not greater than that of the panelboard. This overcurrent device shall be located within or at any point on the supply side of the panelboard.
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Thanks so much

Thanks so much

Thanks for the answers guys. I suspected it was fine as is but I wanted a check by people that know the code.

Since there was interest in why we use 3-phase power I'll give you the answer. We manufacture full motion, high-dynamics antennas ranging in size from 5m to 13m. The antennas are driven by brushless DC motors. The motors are driven by a PWM amplifier for speed and torque control. The amplifiers are 3-phase amps.

So the guy that mentioned the motors was basically right. It's not a 3-phase motor but the motor amplifiers do require 3-phase.

Thanks again.
 
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