Mitsubishi Electric MXZ-SM72TAM-U1 Service Manual page 176

6. Electrical work
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:
• Please turn off the main power supply when servicing. And do not touch the B1, B2 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.)
• Turn on the main power when the ambient temperature is -20°C (-4°F) or higher.
• Under conditions of -20°C (-4°F), it needs at least 4hr stand by before the units operate in order to warm the electrical parts.
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 inter-
mediate connection point.
en
31
2 poles isolator (Switch)
B1
Outdoor unit
B2
Branch box
L1
L2