North Carolina Department of Insurance Office of State Fire Marshal Risk Management State Electrical Division 2017 State Electrical Code 440.6 - Air-Cond. & Refrigerating Equip. Branch Circuit Ampacity & Protection

Notice: The following illustrations are approved by the State Electrical Division of the North Carolina Department of Insurance, Office of State Fire Marshal. These illustrations are intended to demonstrate but not supersede the official written interpretations found at the following web address: http://www.ncdoi.com/OSFM/State_Electrical_Division//Default.aspx?field1=State_Electrical_Code_and_Interpretations Joseph Starling Chief State Electrical Engineer & Inspector Illustrated by: Danny Thomas State Electrical Inspector

MINIMUM CIRCUIT AMPACITY 26.3 AMPS MAX FUSE / BREAKER (HACR) 45 AMPS Date: June 12, 2018 2017 Electrical Code Subject: Air-Conditioning and Refrigeration Equipment Branch Circuit Ampacity and Protection Section: 440.6 45 26.3 Examples of the information found on a nameplate of a typical heat pump MINIMUM CIRCUIT AMPACITY 26.3 AMPS MAX FUSE / BREAKER (HACR) 45 AMPS Question 1: Is the overcurrent protective device for a heat pump branch circuit allowed to be greater than the ampacity of the circuit conductors as specified in 240.6(D) and 310.15(B)(16)? Requires a No. 10 conductor

Date: June 12, 2018 2017 Electrical Code Subject: Air-Conditioning and Refrigeration Equipment Branch Circuit Ampacity and Protection Section: 440.6 Answer 1: Yes. According to section 240.3, Articles 440 and 430 modify the general rules of Article 240 when determining the circuit ampacity and the overcurrent devices for air-conditioning equipment and motors. Typically, newer air-conditioning equipment is listed with a nameplate that provides the installer with the information similar to the example above. Section 440.6 requires the installer to adhere to the data provided on the nameplate of the heat pump where the information conflicts with the general rules of Article 240.

Requires a No. 10 conductor At 60° = 30 amperes At 75° = 35 amperes Date: June 12, 2018 2017 Electrical Code Subject: Air-Conditioning and Refrigeration Equipment Branch Circuit Ampacity and Protection Section: 440.6 45 26.3 Answer 1: Illustration 1 Requires a No. 10 conductor At 60° = 30 amperes At 75° = 35 amperes

Date: June 12, 2018 2017 Electrical Code Subject: Air-Conditioning and Refrigeration Equipment Branch Circuit Ampacity and Protection Section: 440.6 Question 2: Is a circuit breaker or fuse required to be sized at the maximum rating listed on the nameplate of the heat pump when the minimum overcurrent protection is not mandated by the manufacturer? 45 26.3

Date: June 12, 2018 2017 Electrical Code Subject: Air-Conditioning and Refrigeration Equipment Branch Circuit Ampacity and Protection Section: 440.6 Answer 2: No. The maximum rating listed on the nameplate of the heat pump cannot be exceeded, but the electrical code does not prohibit the overcurrent protection to be sized less than the maximum rating listed on the appliance. A manufacturer mandating a minimum rating of an overcurrent protection device will provide such information on the nameplate of the heat pump or in the manufacturer’s instructions as a requirement. A recommendation from the manufacturer shall not be enforced as a requirement.