Transformer connections

[reyamkram]

I always have been connecting Transformers with the primary. In conduit or seal tight and the secondary. In the another. Today. I came across a Transformer with the primary and secondary in the same Raceway?, Is that proper??.

Also, when I'm connecting a Transformer, nowadays do I use a grounding bushing and bond each end of the raceway to the disconnect and Transformer? It is a separately derive system, this Transformers going to feed a machine.

Thank you for any and all information.

 

[jaggedben]

I don't believe that there is a general prohibition on primary and secondary in the same raceway. However the conductors would all need to be rated for the higher voltage, so if the primary is over 600V I think you will find that it is prohibited from a practical point of view. The systems would also need to be marked with different colors to distinguish systems.

 

[jaggedben]

Grounding bushings are not strictly required, but you need adequate bonding by some means or other and I think many would consider grounding bushings good practice.

 

[reyamkram]

I don't believe that there is a general prohibition on primary and secondary in the same raceway. However the conductors would all need to be rated for the higher voltage, so if the primary is over 600V I think you will find that it is prohibited from a practical point of view. The systems would also need to be marked with different colors to distinguish systems.

Thank you very much for the information

 

[infinity]

I always have been connecting Transformers with the primary. In conduit or seal tight and the secondary. In the another. Today. I came across a Transformer with the primary and secondary in the same Raceway?, Is that proper??.

Also, when I'm connecting a Transformer, nowadays do I use a grounding bushing and bond each end of the raceway to the disconnect and Transformer? It is a separately derive system, this Transformers going to feed a machine.

Thank you for any and all information.

Bonding bushing are generally not required. If you have the primary and secondary in the same raceway and it's longer than 24" derating will be required but it is permitted.