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#87304 - 02/09/04 03:44 PM x-frmr secondary protection??
Edward Offline

Registered: 12/14/02
Posts: 309
Loc: California
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?


2014 / 2011 NEC & Related Books and Study Guides
#87305 - 02/09/04 03:49 PM Re: x-frmr secondary protection??
Ryan_J Offline

Registered: 08/19/03
Posts: 1355
Loc: West Jordan, Utah, USA
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.
Ryan Jackson,
Salt Lake City

#87306 - 02/09/04 03:55 PM Re: x-frmr secondary protection??
iwire Offline

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
Buck Boosts are autotransformer's and are only required to have primary protection.

450-4(a) 1999 or 2002
Bob Badger
Construction & Maintenance Electrician

#87307 - 02/09/04 04:02 PM Re: x-frmr secondary protection??
Bjarney Offline

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
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).]


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