Electrical Work; Before Electrical Work; Power Cables And Device Capacity - Mitsubishi Electric CITY MULTI PURY-P-ZKMU-A Installation Manual

10. Electrical work

Electrical work must be performed by qualified personnel in accordance with local regulations and the
instructions provided in this manual. Only use the specified cables and dedicated circuits.
- Inadequate power source capacity or improper electrical work will result in electric shock, malfunction, or fire.
Proper grounding must be provided by qualified personnel.
- Improper grounding may result in electric shock, fire, explosion, or malfunction due to electrical noise. Do not
connect the ground wire to gas or water pipes, lightning rods, or telephone ground wires.

10-1. Before electrical work

・When performing electrical work, refer to the indoor unit or controller installation manuals as well.
・Bear in mind ambient conditions (ambient temperature, direct sunlight, rain water, etc.) when proceeding with the wiring and connections.
・When opening or closing the front panel of the control box, do not let it come into contact with any of the internal components.
・Specific wiring requirements should adhere to the wiring regulations of the region.
・Include some slack in the wiring for the control box on the indoor and outdoor units, because these boxes are sometimes removed at the time of
service work.

10-2. Power cables and device capacity

Include some slack in the power cables.
- Failure to do so may break or overheat the cables, resulting in smoke or fire.
Install an inverter circuit breaker on the power supply of each unit.
- Failure to do so may result in electric shock or fire.
Only use properly rated breakers (an earth leakage breaker, local switch <a switch + fuse that meets local
electrical codes>, or overcurrent breaker).
- Failure to do so may result in electric shock, malfunction, smoke, or fire.
Only use standard power cables of sufficient capacity.
- Failure to do so may result in current leakage, overheating, smoke, or fire.
Tighten all terminal screws to the specified torque.
- Loose screws and contact failure may result in smoke or fire.
If a large electric current flows due to a malfunction or faulty wiring, earth-leakage breakers on the unit side
and on the upstream side of the power supply system could both operate. Depending on the importance of
the system, separate the power supply system or take protective coordination of breakers.
・Wiring example
Ⓐ
Z(S)KMU: 3~575 V
L1, L2, L3
Ⓐ
~208–230 V
L1, L2
・Be sure to use the appropriate type of overcurrent breaker. Note that generated overcurrent may include some amount of direct current.
・Select the type of breaker for an inverter circuit as an earth leakage breaker. (Mitsubishi Electric NV-C series or its equivalent)
・The earth leakage breaker should be used in combination with a local switch.
・Use a local switch with at least 3 mm (1/8 in) contact separation in each pole.
・If the power cable is damaged, it must be replaced by the manufacturer, its service agent or similarly qualified persons in order to avoid a hazard.
・Use dedicated power cables for the outdoor unit and indoor unit. Ensure OC and OS are wired individually.
WT07828X01
Ⓑ
Ⓒ
Ⓕ
Ⓖ
Ⓑ
Ⓔ Ⓔ
Ⓕ Ⓕ Ⓕ
GB-28
Ⓐ Earth leakage breaker
Ⓑ Local switch (Overcurrent breaker
and earth leakage breaker)
Ⓗ
Ⓒ Outdoor unit
Ⓓ Pull box
Ⓓ
Ⓔ
Indoor unit
Ⓕ Ground
Ⓖ Standard or main BC controller
Ⓗ
Sub BC controller
Ⓔ Ⓔ
Ⓕ