Mitsubishi Electric PUMY-P112VKM1 Installation Manual page 16

6. Electrical work
Warning:
• Be sure to use specified wires to connect so that no external force is imparted to terminal connections. If connections are not fixed firmly, it may cause heat-
ing or fire.
• Be sure to use the appropriate type of overcurrent protection switch. Note that generated overcurrent may include some amount of direct current.
• Be sure to attach the terminal block covers/panel of the outdoor unit securely.
If it is not attached correctly, if could result in a fire or an electric shock due to dust, water. etc.
Caution:
• Be careful not to make mis-wiring.
• Firmly tighten the terminal screws to prevent them from loosening.
• After tightening, pull the wires lightly to confirm that they not move.
• If the connecting wire is incorrectly connected to the terminal block, the unit does not operate normally.
• Some installation site may require attachment of an earth leakage breaker. If no earth leakage breaker is installed, it may
cause an electric shock.
• Do not use anything other than breaker and fuse with correct capacity. Using fuse and wire or copper wire with too large
capacity may cause a malfunction of unit or fire.
IMPORTANT
Make sure that the current leakage breaker is one compatible with higher harmonics.
Always use a current leakage breaker that is compatible with higher harmonics as this unit is equipped with an inverter.
The use of an inadequate breaker can cause the incorrect operation of inverter.
Never splice the power cable or the indoor-outdoor-branch box connection cable, otherwise it may result in a smoke, a fire or communication failure.
Warning:
• In case of A-control wiring, there is high voltage potential on the S3 terminal caused by electrical circuit design that has no electrical insulation between
power line and communication signal line. Therefore, please turn off the main power supply when servicing. And do not touch the S1, S2, S3 terminals when
the power is energized. If isolator should be used between outdoor unit and branch box/indoor unit and branch box, please use 3-pole type or 2-pole type.
(Please refer to figure below.)
Outdoor unit
Caution:
After using the isolator, be sure to turn off and on the main power supply to reset the system. Otherwise, the outdoor unit may not be able to detect the
branch box(es) or indoor units.
Be sure to connect the outdoor-branch box/indoor-branch box connecting cables directly to the units (no intermediate connections).
Intermediate connections can lead to communication errors if water enters the cables and causes insufficient insulation to ground or a poor electrical contact at the intermediate connection point.
(If an intermediate connection is necessary, be sure to take measures to prevent water from entering the cables.)
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2 poles isolator (Switch)
B1 L1
B2 L2
GR
Branch box
Loosen terminal screw.
Terminal
Lead wire
block
Connection details