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MINIMUM CIRCUIT AMPACITY & MAXIMUM FUSE SIZE
MINIMUM WIRE SIZE
•
Allowable Ampacities of Insulated Conductors
Single-phase heat pump water heaters are two wire circuits.
Three-phase heaters are three wire circuits. In addition to the
foregoing, a grounded conductor is required. Not more than
•
MINIMUM WIRE SIZE
three conductors in raceway, cable, or earth (directly buried),
Allowable Ampacities of Insulated Conductors
based on ambient temperature of 30°C (86°F)
Single-phase heat pump water heaters are two wire circuits. Three-phase heaters are three wire circuits. In addition to the for
a grounded conductor is required. Not more than three conductors in raceway, cable, or earth (directly buried), based on a
temperature of 30°C (86°F)
MINIMUM WIRE SIZE
TABLE 3
Allowable Ampacities of Insulated Conductors
Single-phase heat pump water heaters are two wire circuits. Three-phase heaters are three wire circuits. In addition to the foregoing,
a grounded conductor is required. Not more than three conductors in raceway, cable, or earth (directly buried), based on ambient
temperature of 30°C (86°F)
TABLE 3
+The load current rating and the overcurrent protection for these conductors shall not exceed 15 amperes for 14 AWG. 20 amperes for 12 AWG and 30 ampere
+The load current rating and the overcurrent protection for these conductors shall not exceed 15 amperes for 14 AWG. 20 amperes for 12 AWG and 30 amperes for
10 AWG copper; or 15 amperes for 12 AWG and 25 amperes for 10 AWG aluminum and copper-clad aluminum.
10 AWG copper; or 15 amperes for 12 AWG and 25 amperes for 10 AWG aluminum and copper-clad aluminum.
*For dry locations only. See 75°C column for wet locations.
*For dry locations only. See 75°C column for wet locations.
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servicing the water heater, make sure
the electrical supply to the water heater
is turned "OFF."
•
Failure to do this could result in death,
Electrical Shock Hazard
serious bodily injury, or property
Before removing any access panels or
damage.
servicing the water heater, make sure
the electrical supply to the water heater
is turned "OFF."
Failure to do this could result in death,
serious bodily injury, or property
damage.
Table 2 on page 15 provides the MCA (Minimum Circuit
C - Compressor
Ampacity) and MFS (Maximum Fuse Size). Use MCA to select
the minimum field wires size to power the unit and MFS to select
the maximum fuse size for over current protection as follows:
Where:
MCA= C x 1.25
MFS = C x 2.25
C - Compressor
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