Disconnector Sizing

[alanElec]

Dear Sirs,
I am working in an HVAC contracting company.We use feild disconnectors at site near equipments like AHU'S,package units etc..Could anyone enlighten how to size disconnector for such applications? Please note that the purpose of disconnector is for isolation and maintanence and does not perform any protection.For eg.if I have an AHU of 3 KW ,FLA 5.8 ,What rating of local/feild disconnector should I use..?

Thanks & Regards,

Alan Sam Baby

 

[collies99]

Size it for the operating voltage level and the maximum load current. Possibly have a current rating much larger than you max loading.

Get one with lockable feature.

 

[collies99]

Also get the appropriate enclosure for the environment.

 

[waross]

Some codes may require sizing at 125% for continuous loading.
Some codes and applications may require the device to be HorsePower rated.

Bill
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