ECN Forum Forums Code Related Discussion NEC & other Code issues x-frmr secondary protection??

I am installing a Buck&Boost transformer. Do i need to have a secondary OCPD.I tried to find it in the 1999 handbook(nec) no luck.

When does an installation require secondary protection?

Merci
Edward.

You will probably only have to supply overcurrent protection on the primary side. 450.6(A) and (B) discuss a couple of instances in which secondary OCPD's are required.

Buck Boosts are autotransformer's and are only required to have primary protection.

450-4(a) 1999 or 2002

They're covered in 99NEC 450-4(a) Autotransformers… Secondary overcurrent protection is generally not required, but also note when “secondary” [shunt] OCP is prohibited.




[This message has been edited by Bjarney (edited 02-09-2004).]