Paul Polakoff
Member
After reviewing 250-21 are my systems allowed to be an ungrounded?
Down stream of my service I have medium voltage switchgear feeding some transformers. 4160 delta primary 600 wye secondary. 4160 again to 480 wye sec.
Neither secondary use the x/o tap for bonding. The systems are ungrounded to the transformers.
The 600 volt system is a single VFD 1500 hp
The 480 volt system feeds an MCC with muti type loads.
I read 250-21 and feel my system does not qualify to be ungrounded, do to primary voltage and mcc loads.
Does anyone feel my system qualifies to be ungrounded?
Thank You
Paul
Down stream of my service I have medium voltage switchgear feeding some transformers. 4160 delta primary 600 wye secondary. 4160 again to 480 wye sec.
Neither secondary use the x/o tap for bonding. The systems are ungrounded to the transformers.
The 600 volt system is a single VFD 1500 hp
The 480 volt system feeds an MCC with muti type loads.
I read 250-21 and feel my system does not qualify to be ungrounded, do to primary voltage and mcc loads.
Does anyone feel my system qualifies to be ungrounded?
Thank You
Paul