Toshiba JK 720 Instruction Manual page 17

Basic Installation and Operation Guide
Special attention should be paid to protection for operating personnel, to protection of equipment itself (e.g. ground
fault relays), and protection of sensitive transducers or control devices that are electronic in nature.
The following may be used as a general guide with regard to equipment grounding.
Controller used as service equipment for a grounded system or as a main section for a separately derived system:
a. The grounding electrode conductor (ground wire) sized in accordance with NEC 250 should be run from the
grounding electrode to the controller ground bus or ground terminal.
b. Unless already done at the factory, a main bonding jumper should be installed from the incoming grounded
connector bus (neutral) to the ground bus or designated grounding point. If a jumper is not furnished, one having
a size in accordance with NEC 250 should be selected.
c. Steps (a) and (b) should effectively connect together the grounding electrode, the controller frame, all outgoing
equipment grounding conductors, and the grounded neutral bus of the system.
d. No connection should be made to ground on the load side of any neutral disconnecting line or any sensor used
for ground fault protection. No connections should be made between outgoing grounding connectors and the
neutral.
e. Where the controller or system is dual-fed (double-ended) and has ground fault protection, special
precautions are necessary to accomplish proper grounding and bonding.
Controller used as service equipment for an ungrounded system or as a main section for a separately derived
system:
a. A grounding electrode conductor (ground wire) sized in accordance with NEC 250 should be run from the
grounding electrode to the controller ground bus or ground terminal.
b. If the system is grounded at any point ahead of the controller, the grounded conductor should be run to the
controller in accordance with NEC 250 and connected to the ground bus or ground terminal.
c. Steps (a) and (b) should effectively connect together the grounding electrode, the controller frame, all outgoing
equipment grounding connectors, and any grounded conductor which runs to the controller.
Controller not used as service equipment or as a main section for a separately derived system, and used on either
a grounded or ungrounded system:
a. The controller frame and any ground bus should be grounded by means of equipment grounding conductors
having a size in accordance with NEC 250 and run with the main supply conductors or by bonding to the
raceway enclosing the main supply conductors in accordance with NEC 250.
TOSHIBA
JK Series 720 Controllers
6