Transformer Isolations Query

[hallmg]

Hello,

The query i have is when performing isolations on transformers, why is the transformer secondary breaker opened first?

Any help would be much appreciated.

Regards,
Hallmg.

 

[ppedUK]

Mainly to prevent any back-feeds from the LV system appearing on the HV "Circuit" side when carrying out the HV isolation.

 

[waross]

Opening the secondary first take the load off the transformer so the primary breaker has only to interrupt no-load current.

Bill
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"Why not the best?"
Jimmy Carter

 

[hallmg]

Hi,

Thank you very much for the advice.

Hallmg.