Code/UL/IEEE requirements (was system expansion) [RE-wrenches]

[Joel Davidson]

<x-flowed>

John,

"Code/UL/IEEE requirements are driving costs up" is an understatement. Last 
year, Americans installed 101 MW of on-grid PV. Granted that's up 58% from 
2005, but annually the Japanese have been installing 100s of MW, Germans 
install GW and other Europeans are installing an ever increasing number of 
MW. I don't know why some people feel the need to inhibit the freedom and 
creativity that once made America a leader in power technology innovation. 
We've degenerated from a nation going boldly where no one has gone before 
to...(you fill in the blank).

Joel Davidson


----- Original Message ----- 
From: "John Berdner" <jberdner at sma-america.com>
To: <RE-wrenches at topica.com>
Sent: Friday, August 24, 2007 1:09 PM
Subject: Re: FW: system expansion [RE-wrenches]


>
> Sky/Wrenches:
>
> I can only speak for my own experience with UL testing of plastic
> parts.
> First you put thermo couples on the part that is being tested.
> You then run the device at the maximum rating and at the specified
> ambient temperature.
> For most components you find today the temperature of the test was
> 25C.
> You are allowed to scale the temperatures up to an ambient of 40C, i.e.
> just add 15C to the 25C data.
> Above 40C you have to run the test at the specified ambient
> temperature, i.e. you can't just add 20C to 25C data to get 45C
> ratings.
> UL then looks up the characteristics of the particular plastic for
> deformation and sees if you pass of fail.
>
> I am not saying I buy the argument of the plastics deforming before the
> breakers open.  I believe what the SquareD guy was saying is that they
> had not tested their panels with the added thermal loading of a bunch of
> additional PV breakers in the panel.  At 120% he was not really
> concerned but he was concerned if we changed to code to allow higher
> levels of PV in the panel.  The concern the 120% rule is trying to
> address is a situation where the PV breaker is installed at the top of
> the bus bar just under the main lugs.  Using a 200 Amp panel with an
> additional 100 Amps of PV breakers as an example: Someone theoretically
> could put 300 Amps of load breakers in the panel and no over current
> devices would trip even though the bus bar could be at 150% of it's
> design current.  Frankly, I do not buy this argument either since you
> would inevitably end up with nuisance tripping of the main breaker on
> cloudy days, in the morning, at night, etc.
>
> As you pointed out, there is NO ISSUE of bus bar rating if you put the
> PV breakers at the bottom of the bus bar.  As long as the total of the
> PV is less than the bus bar rating, you can not create a scenario where
> the bus can be overloaded.  This was the position we (the PV industry)
> were arguing and trying to get into the 2008 Code.  The sub panel
> manufacturers argued against this and won.  Hmmm...do load center
> manufacturers make more money by selling a 400 Amp panel where a 200 Amp
> panel would be adequate ?
>
> I personally would like to see another Code approved alternative in the
> form of a labeling requirement for panels with a mix of generation and
> load breakers.  If the panel has a mixture of load and generation
> breakers then it should be labeled as such and have a Code required
> label that says the total of all the generation breakers can not exceed
> the rating of the bus bar AND the total of all the load breakers cannot
> exceed the rating of the bus bar.  While there is no perfect solution at
> least under the labeling scenario we could use panels up to their full
> rating instead of having to double the size of the panel for nothing.
>
> I agree that PV systems need to be safe but >> IMHO <<  our
> Code/UL/IEEE requirements are driving costs up to cover hypothetical
> situations that are extremely unlikely.   I whole heartedly agree with
> you that we need to have ore balance between risk and cost or we are
> never going to get costs down. Installation costs in the US are roughly
> double those in Europe or Japan and both of those places have high cost
> labor just like we do. Sometimes it seems like some of the guys on the
> regulatory committees are trying to use regulations to keep stupid
> people from stupid things.  As a good friend of mine is fond of saying
> "All the regulations in the world won't stop someone from putting gas in
> his diesel truck".
>
> The first meeting for the 2011 Code will be at Solar Power 2007.  If
> people want to be involved in the process get in touch with John Wiles
> and tell him you want to participate.  I can tell you it is pretty mind
> numbing sometimes but occasionally we do get rid of bad requirements or
> add some new ones that make sense.  In the past I feel the installers
> have been under represented and I, for one, would love to see more input
> with real world perspective.
>
> Best Regards,
>
> John Berdner 


- - - -
Hosted by Home Power magazine

To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael_welch at sbcglobal.net

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------



</x-flowed>