Wacky Weekend: NERC to relax power grid frequency strictures

Jay Ashworth jra at baylink.com
Sun Jun 26 16:27:33 UTC 2011

----- Original Message -----
> From: "Jeff Wheeler" <jsw at inconcepts.biz>

> On Sun, Jun 26, 2011 at 12:23 AM, Alex Rubenstein <alex at 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.

-- jra
Jay R. Ashworth                  Baylink                       jra at 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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