RE; Breaker hold down kit [RE-wrenches]

[Jason Fisher]

Matt's has an excellent point when recommending that we describe an inverter
as an "interactive" devise. To support this we can point out that the
inverter also operates as a load which draws power from the grid to energize
the transformer windings and operate it's controls. Turn off the PV breakers
to demonstrate this.

I would also add that pointing out that inverter AC conductors are "branch
circuits" and not "feeders" may aid in keeping an inspector on Earth with
regards to these issues.

In Vince's case however, this may not help since the inspector has already
made a decision, which is always difficult to reverse. I'd take EH's advise
and discuss the idea of a service tap with the inspector. You could also use
a fused disconnect rated for use as "service entrance equipment" for this in
addition to the load center suggestion. The taps rules are tricky though,
not to mention the issue of how do you de-energize the feeders to make this
tap in a method that is acceptable to the utility. I wouldn't recommend this
work be done hot!

Jason Fisher
AE
-----Original Message-----
From: mlafferty at universalenergies.com
[mailto:mlafferty at universalenergies.com]
Sent: Friday, September 05, 2003 9:10 AM
To: RE-wrenches at topica.com
Subject: RE: RE; Breaker hold down kit [RE-wrenches]

Vince asks:

I was wondering if anyone on the wrenches list might know where I can
find a hold down kit for a Murry 15 amp 2 pole circuit breaker as
required in NEC article 408.16 F. I have tried all my local sources and
the only thing I could find was a small plastic clip that only works for
breakers over 70 amps. My inspector wants to see any back fed circuit
breaker such as with a grid tie PV system held in place . It seems to me
that NEC article 408.16 F was not written with grid tie inverters in
mind because as soon as you disconnect the circuit breaker the inverter
stops powering the breaker anyway.

All:

This has been an ongoing "issue" since the beginning of time.  I haven't
heard it brought up lately so, perhaps we need a refresher.... There are
some inspectors out there that still have never seen one of these
things... Yet.

First thing: The following applies to Grid Connected, non-backup capable
inverters only!

Finding a "hold-down" for various breakers and panels is indeed tough.
Even if you can find a hold-down, invariably there are no provisions in
the panel at the location you selected for the inverter breaker.  Don't
waste your time!  Invest the same amount of time in educating the
inspector!  If you don't, you will be forever required to go through the
needless exercise of trying to find and install a hold-down.

Vince, you are on the right track when you recognize that the inverter
"dies" when the AC is shut off.  This is because of the Anti-Islanding
circuitry in the inverter.  My rule is to NEVER breathe the word
"Backfeed".... It is "Interactive".  It can only "Interact" as long as
the grid is present.  I explain this principle to the Inspectors.  Most
have a tough time accepting it... In their mind it "still has to
backfeed through that breaker there to get back to the grid"... "If that
meter there is turning backward, it must be backfeeding"....

The most common way I've dealt with this is to demonstrate it.... Put
your Voltage tester on the lugs of the breaker with everything operating
then turn the breaker off.  Volts go to Zero.  Inspector's eyebrows
raise and his/her head nods in amazement.... Every time.  Well, except
one... Back in '99.... More dramatic and "not recommended" tactics were
necessary....

***Do not attempt this at home!  The following was performed by a
professional Jackass!***

In the case of the "extra stubborn inspector", this guy was convinced
that I "must have turned something else off, too".  I turned the system
back on and waited for it to come up to full power.  I didn't move from
the AC panel.  Once he was convinced that everything was on, I turned
off the AC breaker, removed the leads and put them in my hand.  He never
gave me any "backfeed" grief after that.

Peace and Good Luck!

Matt Lafferty
Universal Energies Institute
mlafferty at universalenergies.com
(916) 422-9772
(916) 628-7694 Cell
(916) 914-2247 Fax
www.universalenergies.com

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