[RE-wrenches] Line side taps in Hawai'i

Bill Brooks billbrooks7 at yahoo.com
Mon May 21 18:19:26 PDT 2012


James and all,

Sorry to hear my time in Hawaii did "no good." I think I'll quit....

Seriously though, the discussions in several of my Hawaii workshops centered
around "load-side" taps, not line-side service connections (don't like to
call them taps). A tap is a type of connector. 

Since we did not discuss line-side connections much, I can understand how it
didn't help. There is a lot of misunderstandings about these types of
connections. If you have a 100-amp service, then your PV system is only
limited by the size of the service conductors. An 80-amp continuous PV
inverter could be connected through a 100-amp OCPD into a 100-amp feeder
upstream of the first overcurrent device provided a legal, listed connection
could be made at that point. If the meter base or service panel does not
have a means to make this connection (as pointed out in detail in previous
posts), a junction box could always be installed upstream of the service
panel to make a connection. AHJs may reject this idea, but it is only
because they don't understand it or it hasn't been explained properly.

Bill.


-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Dave Click
Sent: Monday, May 21, 2012 5:46 AM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] Line side taps in Hawai'i

Square D probably has a similar "solar-ready" panel; I remember seeing some
monster (4' tall? they were big) Cutler Hammer panelboards at SPI
2010 that had it too. On my house I have a Square D RC2M200S which has
simply a 200A main plus a 2P 50A breaker (perfect for PV). This is a much
smaller enclosure (18"H x 20"W) than some others I've seen, but with limited
functionality; no load breakers can be added here which can be a problem
when using it in a retrofit.

This is an issue for the combination service entrance devices as the
conductors from the utility meter load terminals to the main breaker are
factory-installed and can't be touched. I did an inspection two years ago
where the installing contractor's solution was to interconnect the PV on the
utility side of the meter. This is not a solution.

If the issue is that "nobody is allowing line side" connections then you're
sorta stuck. As for why the AHJ wouldn't allow it, they should be willing to
share their justification with you! If the issue is as Jeffrey's
encountered-- they're requiring listed enclosures where line-side
connections are made-- then you can get around it either with these Milbank
dual lugs

http://www.milbankmfg.com/products/Catalogs/CatalogFiles/PDF/K4977.pdf#Tap%2
0Connector

or the aforementioned Cutler Hammer or Square D panels. It may be that
they've heard about the "listed enclosure" requirement and naively
generalized it beyond code requirements. If they're asking for service
upgrades, then perhaps they're thinking that a 200A service + 100A PV
requires a 300A service-- if it's not battery backup, a simple power flow
diagram may prove to them that a 200A service is perfectly adequate.

On 2012/5/19 17:52, JRQ wrote:
> I had a similar problem working in San Diego. SDG&E insisted that no 
> taps could be performed in an enclosure unless the contractor could 
> supply documentation that the enclosure was specifically listed for a 
> tap, or if an electrical engineer supplied stamped drawings of the tap.
> I never did a project that warranted hiring an engineer, so I don't 
> know what they were looking for there.
>
> I heard that Square D (or maybe it was one of the other companies) has 
> a new "solar-ready" service panel with a lug on the line side for a 
> solar input. You could use the same feeders and service size with a new
panel.
>
> Jeffrey Quackenbush
> NABCEP certified PV installer
> Peripatetic Solar Technician
>
> ----------------------------------------------------------------------
> --
> *From:* James Rudolph <jamesrudolph99 at gmail.com>
> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
> *Sent:* Wednesday, May 16, 2012 10:48 PM
> *Subject:* [RE-wrenches] Line side taps in Hawai'i
>
> Aloha Wrenches,
>
> I have recently started working in Hawaii on the island of Oahu and 
> have run into some interesting problems with the AHJ's. The biggest 
> issue is nobody is allowing line side taps on the island, so most of 
> are larger systems are requiring service upgrades, this also requires 
> replacing the feeder of course and plenty of trenching which adds so 
> much time and cost to the whole process.. Now I know Bill Brooks was 
> on island recently and and this seems to have done no good. I was 
> wondering if anybody can shed some light on this issue and the reasons 
> why they would not allow this code compliant option. This is allowed 
> on commercial systems here just not residential to be clear.
>
> And If your out there Bill, do you have any suggestions on how to 
> approach this matter with the local inspectors???
>
> Mahalo,
>
> --
> *
> James B Rudolph*
> *Heleakala Solar* *
> *
> *Director of Construction*
> *NABCEP Certified PV Installer*
> *
> *
> *
> *
> *
>
> *Don't get me wrong: I love nuclear energy! It's just that I prefer 
> fusion to fission. And it just so happens that there's an enormous 
> fusion reactor safely banked a few million miles from us. It delivers 
> more than we could ever use in just about 8 minutes. And it's wireless!
> - William McDonough
>
>
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