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Re: Wacky Weekend: NERC to relax power grid frequency strictures


From: Jay Ashworth <jra () baylink com>
Date: Sun, 26 Jun 2011 12:27:33 -0400 (EDT)

----- Original Message -----
From: "Jeff Wheeler" <jsw () inconcepts biz>

On Sun, Jun 26, 2011 at 12:23 AM, Alex Rubenstein <alex () corp nac net>
wrote:
At least here in JCPL territory (northern NJ), closed transition is
frowned upon. Too much risk, they think. They are correct, really,
but the risk is mostly yours. If you lock to the utility
out-of-phase, you will surely lose and they will surely win. The
fault you create that they will see will probably not hurt them.
Unless it is extraordinarily large and you are very close to the
nearest substation.

Utilities concern themselves with not only their gear and your gear,
but also your neighbor's gear. I would not like to be next-door to a
large genset that is connected to the grid out-of-phase. My equipment
would be affected by such an event.

More to the point, as I note in another reply, you don't want to be
*the lineman down the road with his hands on a "dead" wire*.

Pretty much the *first paragraph* in NEC 700 (700.6) says this:

"""
Transfer equipment shall be designed and installed to
prevent the inadvertent interconnection of normal and
emergency sources of supply in any operation of the trans-
fer equipment.
"""

So, if your transfer switch is *physically* capable of connecting your
genset to the incoming power wires, then it violates 700.6, unless you're
in a cogen sort of environment, in which case you're following Article 705,
and a whole different set of rules apply.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274


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