GFP on SDHW pv pump? [RE-wrenches]

[Roy Butler, Four Winds RE]

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Joel,

Thanks so much for the best (actually the first) laugh of the day!

We sure can stuck in a loop in this industry! Lemme go move my cheese 
now....lat -15 degrees....

Roy Butler
NABCEP Certified Solar PV Installer®
NYSERDA eligible PV & wind installer 
Four Winds Renewable Energy, LLC
8902 Route 46
Arkport, NY 14807
607-324-9747
www.four-winds-energy.com

Although no trees were killed in the sending of this message, 
a large number of electrons were terribly inconvenienced.




Joel Davidson wrote:

>
> Ground the array. Don't ground the array. Put a GFDI on residential 
> rooftop arrays. Put GFDI on all arrays. Set your Voc to record low 
> temperatures. Set your Isc to 1.25. Set your Isc to 1.56. Move the 
> cheese. Put the piano by the window. Move the piano away from the 
> window. But whatever you do, make PV better quality, faster installed, 
> cheaper for the customer, and profitable for a sustainable industry. 
> Get involved. See 
> http://www.solarabcs.org/stakeholder_mtg_presntations/index.htm
>
> ----- Original Message ----- From: "Mark Frye" <markf at berkeleysolar.com>
> To: <RE-wrenches at topica.com>
> Sent: Friday, November 16, 2007 11:41 AM
> Subject: RE: GFP on SDHW pv pump? [RE-wrenches]
>
>
>>
>> Indeed, but in order to capture the full power of the module the fuse
>> would have to be rated at about the Imax of the module which would be
>> about the same as the Isc so you may as well not have the fuse at all in
>> terms of interrupting the ground fault current.
>>
>> So here we have another massive gap between Code and technology.
>>
>> Incredibly, if you are running a 100kw system, you would set the GFDI
>> trip at what, I forget , 5 amps, 10 amps, 50 amps?
>>
>> Ok, for a 3kw system the GFDI fuse is 1 amps.  Scale it down to a .003
>> kw system and really what rational person would require GFDI in this
>> case.
>>
>> As an aside, in order to be intrinsically safe so yo can be used in
>> Classified Locations (explosive)you can run at up to 1.3 watts.
>>
>>
>> Joel Davidson wrote:
>>
>>>
>>> From the 2005 NEC Code Handbook page 1021: Ground-fault detection and
>>> interruption for PV systems should not be confused with the 
>>> requirements
>>> for
>>> GFCI protection, as defined in Article 100. A GFCI is intended for the
>>> protection of personnel in single-phase ac systems. It functions to 
>>> open
>>> the
>>> ungrounded conductor when a 5-mA fault current is detected. In 
>>> contrast,
>>>
>>> devices meeting 690.5 are intended to prevent fires in dc PV circuits
>>> due to
>>> ground faults.
>>>
>>> I haven't kept up with SDHW system developments, but what's wrong with
>>> using
>>> an in-line, fast-blow fuse on the low-wattage PV module circuit?
>>
>>
>>
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>
>
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>


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