Dual core CT(current tranformer) grounding 1 core ?

[elcomiss]

Hi,

Due to a discussion at our workplace.
If only one of the dual cores are used on the secondary side of the measuring CT(MV-switchgear).

Is it better to short and ground the unused core or to just leave it open ?

Comments to drawbacks and benefits ?

 

[scottf]

There is no option. You must short the unused core and it's best to ground it as well. It will not influence the accuracy of the other core.

Leaving a CT open-circuited is NEVER an option, due to the chance for high-voltage and ultimately damage to the CT, personnel, other equipment, or all of the above.