ECN Forum
Posted By: Edward x-frmr secondary protection?? - 02/09/04 11:44 PM
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.
Posted By: Ryan_J Re: x-frmr secondary protection?? - 02/09/04 11:49 PM
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. [Linked Image]
Posted By: iwire Re: x-frmr secondary protection?? - 02/09/04 11:55 PM
Buck Boosts are autotransformer's and are only required to have primary protection.

450-4(a) 1999 or 2002
Posted By: Bjarney Re: x-frmr secondary protection?? - 02/10/04 12:02 AM
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).]
© ECN Electrical Forums