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MCA and MOCP

MCA is the minimum circuit ampacity and MOCP the maximum overcurrent protection printed on a heat pump's nameplate, used to size its wire and breaker.

Editorial staffEdited by heatpumpwiki

History 1

MCA (minimum circuit ampacity) and MOCP (maximum overcurrent protection) are printed on the outdoor unit's nameplate. The wire must be rated for at least the MCA; the breaker or fuse must not exceed the MOCP.

The National Electrical Code, section 440.4(B), requires the nameplate to show the "minimum conductor ampacity" and "the maximum rating of the branch-circuit short-circuit and ground-fault protective device."Source 1

Example: Mitsubishi's MUZ-FS06, 09 and 12 list an MCA of 10 amps and a maximum fuse of 15 amps.Source 2 See Heat pump electrical requirements.

Sources

  1. 1.Properly Sizing Conductors and Protective Devices for AC and Refrigeration Equipment. EC&M (Mike Holt). Accessed Oct 25, 2026
  2. 2.Service Manual MUZ-FS06NA, MUZ-FS09NA, MUZ-FS12NA, MUZ-FS15NA, MUZ-FS18NA (OBH873 Rev. B). Mitsubishi Electric. Accessed Oct 25, 2026

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