Tag: "gma ring"

03/22/18

  01:24:00 pm, by Jim Jenal - Founder & CEO   , 985 words  
Categories: All About Solar Power, Residential Solar, Safety, Ranting

Sweet Relief - LA County Signs-off on Solar for Center-Fed Service Panels

Due to a misreading of the electrical code, many jurisdictions in the Run on Sun service area - and yeah, we are talking about you, LA County - balked at allowing homeowners to install solar if they were connecting to a center-fed panel.  This has resulted in costly, and unnecessary service panel upgrades, and even prevented some homeowners from adding solar at all!

Well good news - LA County has finally gotten with the program and agreed to interpret the code consistent with the intent of the code’s authors.  Here’s the scoop….

Portion of a center-fed service panel

We have written about this problem at some length before - you can see those articles about solar and center-fed panels here.  The confusion arose because the code calls for connecting the solar breaker to the opposite side of the bus from the main breaker.  Since on a center-fed panel the main breaker is in the middle of the bus, there was no “opposite side” to mount the solar breaker, according to that tortured interpretation.  (In the photo on the right, you can see the large, main breaker in the center, with load breakers above and below it.)

To get around this problem in jurisdictions that held to that view of the code’s intent, various approaches were brought forward, all of them more dangerous and/or complicated than simply putting a solar breaker at one end of the bus.  For example, a couple of years ago, San Diego Gas & Electric introduced an adapter ring to fit between the meter socket and the service meter.   Soon thereafter, SCE adopted a similar solution, and that became our “go-to approach” for center-fed panels in LA County.

While County would sign-off on the SCE ring (or Generation Meter Adapter, as SCE called it), it was really an awful solution to the problem  For one thing, SCE charged the homeowner just under $500 for the install, and their technician had to do the work in full arc-flash protection gear - a testament to the hazard involved.  Beyond that temporary risk, the connection now left a pair of terminals in the solar disconnect with no over-current protection between them and the power pole transformer.  Short that connection out, and nothing would stop that current from flowing until the wires melted!

A better solution was recently brought to market in the form of the B3-Bypass breaker which we wrote about last Fall.  The B3 fits into center-fed panels and provides a much safer way to interconnect solar than the GMA ring.  But guess what?  Despite it having passed UL certification, LA County will not accept it, as we learned when we attempted to submit plans calling for the installation of the B3!

So, back to square one?  Well not quite.  While on the phone with County’s plan checker, I remembered that a code amendment had been passed effective a year ago January, that clarified the intent of the code when it comes to center-fed panels.  We had cited this amendment to county last year, only to be told that County had not yet approved the amendment - hence we installed multiple GMA rings with center-fed panels last year.

Here’s the language of the amendment:

A connection at either end, but not both ends, of a center-fed panelboard in dwellings shall be permitted where the sum of 125 percent of the power source(s) output circuit current and the rating of the overcurrent device protecting the busbar does not exceed 120 percent of the current rating of the busbar.

This is what we had been saying all along, and the code amendment makes it clear that this is an acceptable thing to do - as well as being cheaper and safer than any of the alternatives.

So, I asked the plan checker, had County gotten any closer to adopting this amendment?  “Oh,” said the plan checker, “we’ve been accepting it since January, 2017!”

Sigh.  So not true.  At least none of the plan checkers that we encountered in 2017 were accepting the amendment.  And for that matter, this plan checker did not volunteer the information.  Instead, he was about to sign-off on the GMA ring without ever bothering to mention that there was a safer and cheaper way for us to meet the needs of our client!  Is it too much to ask that a plan checker point out policy changes of which s/he is aware when discussing plans with a contractor?

Here’s the bottom line:  If your solar project meets the interconnection requirements set forth in the quoted language above, you do not need to upgrade your panel, and you don’t need a GMA ring to attach solar to your center-fed panel in LA County territory.  (And if it satisfies LA County, presumably every other jurisdiction should go along as well.)

If you need documentation - either as a homeowner to provide to your solar contractor who is trying to sell you an unwanted service panel upgrade - or as a solar contractor trying to convince a recalcitrant AHJ - here’s the link to the California Building Standards Bulletin that approves the amendment, and here is Bill Brooks’ write-up explaining the need and justification for the amendment
Here’s the money quote from the latter:

The fact that several thousand center-fed panels in good repair have required replacement over the past two years when, in fact these upgrades are unnecessary, presents a real and unnecessary hazard to the field workers required to perform these replacements. Any time a service equipment replacement is performed on a dwelling, utility service must be interrupted and significant electrical work must be performed to replace the equipment. This exposes the electrical worker to hazards of potentially live conductors and inadvertent errors that could even be fatal. The hazards of these upgrades is appropriate when the existing service equipment is damaged or has outlived its useful safe operating life. Performing these upgrades on perfectly good equipment that is not a safety hazard to the dwelling is an unnecessary risk.

We couldn’t agree more!

 Permalink

09/19/17

  03:48:00 pm, by Jim Jenal - Founder & CEO   , 857 words  
Categories: All About Solar Power, Residential Solar, Safety, Ranting

The Biggest News at SPI 2017 - B3 Bypass

We just got back from Solar Power International 2017 and it featured all the usual players with lots of cool stuff on the (gigantic) floor of the Convention Center at Mandalay Bay.  But the biggest deal of the show, from our massively solar geek perspective, came from a tiny booth that no doubt many folks missed altogether.  But for many of the potential clients that we see, this was a really big deal!  Here’s our take…

The Sad State of Play

Here in SoCal, we find a great many center-fed service panels - that is, a service panel where the main breaker is located in the middle of the bus.  Now in a truly rational world, that wouldn’t matter, but around here, the prevailing view is that you cannot use the “120% Rule” on a center-fed panel.  (I know this is totally in the weeds, but the 120% Rule says that the sum of all breakers supplying a service panel cannot exceed 120% of the bus rating, and that the solar breaker has to be at the opposite end of the bus from the main breaker.)  So, on a 200 A bus, with a 200 A main, the PV breaker is limited to 40 A.  All fine and good, but it is that “opposite end of the bus” that causes some AHJs misery - like LA County - who insists that with a center-fed panel, there is no “opposite end of the bus"!  (Ignore for the moment that if I have a center fed panel with 10 slots above and below the main, I’m out of luck.  But I could have a main panel with a total of 10 slots below my 200 A main, and no one would have a problem with my putting my PV breaker in the bottom slot!)

So, we are presently stuck with an ignorant interpretation of the Code and it has meant that some folks needlessly were forced to upgrade a perfectly good center-fed service panel just to go solar.

GMA ring installedMore recently, SCE allowed the use of the so-called Generation Meter Adapter (GMA) ring, that consists of a spacer between the utility meter and the meter socket, that allowed for a whip connection to the PV system’s AC disconnect.  That got around the 120% Rule since there is no breaker landing on the bus.  BUT - you have an unprotected connection all the way from the pole to that disconnect - which creates a serious hazard, especially in a residential environment.

You can see the interconnection on the right - and the scary danger sticker that we added to provide a suitable warning.  (Interestingly, while we have to add all manner of stupid signage - like that directory plaque that provides no useful information whatsoever - there is no requirement for a warning about the hazard presented by that interconnection.)  To be extra cautious, we also install a lock on the disconnect door to discourage the curious.

Oh, and it costs just under $500 to have SCE install the ring (and their service tech has to suit up to reduce the risk that he gets lit up like a Christmas tree while doing the install).  Geez, all this because of a bad code interpretation!

To the Rescue - B3 Bypass!

Fortunately, there is now an alternative to this madness!  A California-based outfit that goes by the not-so-catchy name of QFE002, has come up with a revolutionary product - that is now UL listed!  (They have been coming to SPI for years, but they just got UL!)

B3 Bypass breakerSo what is this game changer?  It is the B3 Bypass breaker and it taps directly onto the main conductors going into the main breaker.  Because the PV does not go through the bus at all, the 120% rule does not apply.  This means that the amount of current that could be backfed by the PV array is only limited by the main conductors feeding that breaker.

In the picture on the left, the 200 A main breaker is on the bottom and the B3 Bypass breaker is above.  The B3 Bypass clamps down onto two of the four conductors feeding the main.  (They have a nifty tool that strips the insulation off without otherwise modifying the conductors, or unscrewing them from the main breaker.  Per UL, this does not constitute a modification of the panel, so its UL listing is unaffected - meaning that there is no need for a field certification.)

The B3 Bypass comes in various configurations - the dual, twin-pole 20’s shown here  can actually be as high as twin 60’s - meaning that you could install 120 A of solar - triple what could be normally connected to a 200 A service, and twice the 60 A rating of the GMA ring!  It is even 50% more than you could install on a 400 A service!  Yeah, this could be big!

They are taking order requests on their website, although we don’t yet have pricing or timing for potential deliveries.  (My guess is that they are just now trying to move into production mode, now that UL is behind them.)  We passed along their info to both BayWa and CED Greentech - hopefully they will get a distribution deal going so that they can make this available far and wide!

We are definitely fans!

Jim Jenal is the Founder & CEO of Run on Sun, Pasadena's premier installer and integrator of top-of-the-line solar power installations.
Run on Sun also offers solar consulting services, working with consumers, utilities, and municipalities to help them make solar power affordable and reliable.

Ready to Save?

Let’s Get Started!

Give Us a Call!

626.793.6025 or
310.584.7755

Click to Learn More About Commercial Solar Power!

We're Social!



Follow Run on Sun on Twitter Like Run on Sun on Facebook

Search

Run on Sun helps fight Climate Change
CMS + user community