LO/TO of 4KV Switchgear

[MBM76]

We are discussing safe isolation of a 4KV switchgear at my workplace to allow maintenance and inspection on the buss and infeed cubicles. The switchgear normally operates single-ended, fed from one of the two infeeds. Both 4KV infeed lines and open and grounded, including the PT's.

My question is about whether or not the Buss Potential Transformer needs to be isolated to avoid the possibilty of backfeed?

Thanks
Mark

 

[MBM76]

We are discussing safe isolation of a 4KV switchgear at my workplace to allow maintenance and inspection on the buss and infeed cubicles. The switchgear normally operates single-ended, fed from one of the two infeeds. Both 4KV infeed lines and open and grounded, including the PT's.

My question is about whether or not the Buss Potential Transformer needs to be isolated to avoid the possibilty of backfeed?

Thanks
Mark

Failed to mention,
The buss is also grounded via a cubicle installed grounding truck.

 

[zog]

Yes, you need to pull the PT fuses for overpotential testing anyways.