Ocpd and Feeder sizes for heat pumps

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Today I inspected 12 heat pump units on a commercial job. I want to make sure the OCPD and Feeders are sized correctly. All units have supplemental resistance heaters built in. The nameplate data has max amps for the heat pump and a small percentage for backup heat. So, how do I calculate this? Do I add a 125% for the heating elements? Or ???? Any help would be appreciated. Thanks.
 

Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
The nameplate is what you use. There is no calculations to do.

The nameplate should give you the max. OCP and the min. circuit ampacity.

The 125% is included in the nameplate
 
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