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PTX3000 DC Power Electrical Safety Guidelines

The following electrical safety guidelines apply to a DC-powered PTX3000:

  • A DC-powered PTX3000 is equipped with a DC terminal block that is rated for the power requirements of a maximally configured PTX3000. To supply sufficient power, terminate the DC input wiring on a facility DC source capable of supplying at least 51 A @ –48 VDC per input for the DC PSM. Incorporate an easily accessible disconnect device into the facility wiring. In the United States and Canada, the –48 VDC facility should be equipped with a circuit breaker rated a minimum of 125% of the power provisioned for the input in accordance with the National Electrical Code in the US and the Canadian Electrical Code in Canada. Be sure to connect the ground wire or conduit to a solid office (earth) ground. A closed loop ring is recommended for terminating the ground conductor at the ground stud.

  • Run two wires from the circuit breaker box to a source of 48 VDC.

  • A DC-powered PTX3000 that is equipped with a DC terminal block is intended only for installation in a restricted access location. In the United States, a restricted access area is one in accordance with Articles 110-16, 110-17, and 110-18 of the National Electrical Code ANSI/NFPA 70.


    Primary overcurrent protection is provided by the building circuit breaker. This breaker should protect against excess currents, short circuits, and earth faults in accordance with NEC ANSI/NFPA70.