3.1 Main Circuit Wiring3-113 Wiring and Connection3.1.4 General Precautions for WiringTo ensure safe, stable application of the servo system, observe the following precautions when wiring.• Use the cables specified in the multi-winding drive unit catalog. Design and arrange the system so that eachcable will be as short as possible.• Use shielded twisted-pair cables or screened unshielded twisted-pair cables for I/O signal cables andencoder cables.• Use the busbars that are included with the converter and connect the P and N terminals on the SERVOPACKand converter securely.• The maximum wiring length is 3 m for I/O signal cables, 50 m for servomotor main circuit cables andencoder cables, and 10 m for the control power supply cables (+24 V and 0 V).• Observe the following precautions when wiring the ground.• Use a cable as thick as possible (at least 2.0 mm2 ).• Ground the SERVOPACKs and converters to a resistance of 10 Ω or less.• Be sure to ground at only one point.• Ground the servomotor directly if the servomotor is insulated from the machine.• The signal cable conductors are as thin as 0.2 mm 2 or 0.3 mm 2. Do not impose excessive bending force ortension.• Use a molded-case circuit breaker (1QF) or fuse to protect the main circuit.The SERVOPACKs and converters connect directly to a commercial power supply;They are not isolated through a transformer or other device.Always use a molded-case circuit breaker (1QF) or fuse to protect the servo systemfrom accidents involving different power system voltages or other accidents.• Install a ground fault detector.The multi-winding drive unit, SERVOPACKs, and converters do not have a built-inprotective circuit for grounding.To configure a safer system, install a ground fault detector against overloads andshort-circuiting, or install a ground fault detector combined with a molded-case circuitbreaker.• Do not turn the power ON and OFF more than necessary.• Do not use a multi-winding drive unit, SERVOPACK, or converter for applicationsthat require the power to turn ON and OFF frequently. Such applications will causeelements in the multi-winding drive unit, SERVOPACK, or converter to deteriorate.• As a guideline, at least one hour should be allowed between the power beingturned ON and OFF once actual operation has been started.
