Monitoring MV/ LV Ungrounded Systems

[Kiribanda]

Hi all,

Just a quick question!

Is it a code violation (NEC,National Electrical Safety Code or CEC etc.) to build and opearte a MV or a LV high resistance or an ungrounded elctrical power distribution system without at least a monitoring method or an alarm system to detect and indicate possible phase to ground faults?

If so, can any memebr kindly mention the relevant clause number?

Thanks!

Kiribanda

 

[rcw retired EE]

NEC Section 250.36 -"High Impedance grounded neutral systems... shall be permitted for 3-phase ac systems of 480 volts to 1000 volts where all of the following conditions are met:
(1) The conditions of maintenance and supervision ensure that only qualified persons service the installation.
(2) Continuity of power is required.
(3) Ground detectors are installed on the system
(4) Line-to-neutral loads are not served."

part (3) requires it.