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Old March 2nd, 2006, 12:15 AM   #11

Vic is online now
Join Date: Jun 2002
Posts: 236

Allen-Bradley's manual is correct. What you don't realize is that the Amp rating of a Motor Circuit Protector refers to the Frame Size (continuous current rating) of the breaker, not the trip current rating. The instantaneous trip current is usually adjustable as a multiple of the continuous current rating. There is no thermal or overload trip.

See this link for information on the Square D Motor Circuit Protector. The table at the bottom of page 3 shows that a 30 Amp MCP has an adjustable trip range of 90-330 Amps which meets the NEC requirements for a 15 HP @ 480 V motor.

P.S. Are you going to give me a Platinum Star for this?
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