Pad Transformer sectionalizing switch OK for LOTO?

I^2R

Member
Location
NH
Hi,
We need to work on a main breaker of a 480V service. It's fed by a 12,470V -> 277/480Y pad transformer.
Typically (and per our safety policy), we would have the POCO pull the primary cutouts and ground the feeder on the pole that feeds the transformer or pull the loadbreak elbows on the transformer. In this case, due to downstream loads, the POCO wants to put the sectionalizing switch in the pad in the loop thru / transformer open position. We would then place LOTO on the door of the transformer.
Is the sectionalizing switch a reliable means to shut down the pad and suitable for this scenario?

Thanks.
 

paulengr

Senior Member
Hi,
We need to work on a main breaker of a 480V service. It's fed by a 12,470V -> 277/480Y pad transformer.
Typically (and per our safety policy), we would have the POCO pull the primary cutouts and ground the feeder on the pole that feeds the transformer or pull the loadbreak elbows on the transformer. In this case, due to downstream loads, the POCO wants to put the sectionalizing switch in the pad in the loop thru / transformer open position. We would then place LOTO on the door of the transformer.
Is the sectionalizing switch a reliable means to shut down the pad and suitable for this scenario?

Thanks.

No worse than anything else you mentioned.

Utilities have reclosers, disconnects, sectionalizers, and isolation switches. All are legal disconnects per OSHA subsection S. A true disconnect can open safely under fault conditions. A recloser can also close into a fault...it’s essentially a heavy duty breaker. A sectionalizer can open under normal (not faulted) loads. An isolation switch must be opened totally unloaded.

A loop feed means the transformer has two high side inputs that are bus barred internally for convenience (no splices needed). It often has an internal isolation switch that allows disconnecting it internally. If it doesn’t have lockout provisions if you lock the door it can’t be energized on the low side.
 
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