becoming an inter-tie system [RE-wrenches]

Thu Feb 22 12:53:12 PST 2001

<x-flowed>Hi Jay,

I agree that with high voltage systems, extra safety precautions should be 
taken.  Metal conduit would certainly be a good precaution.

On a job I did for Public Service Company of Colorado several years ago, 
the 450 volt, 18 KW system was protected by EMT.  It was a commercial 
building rather than a residence, so no ground fault protection was required.

Best,

Drake ,

At 04:47 PM 02/21/2001 -0800, you wrote:
>Hi Drake,
>
>Thanks for the update.  I bet though that we will see more HI voltage systems
>200v+ and what do you say to the GFI then?  Also with the GFI's built into 
>most of
>the batteryless inverters its not too much of a problem.
>
>But for battery based, yep its a problem.    How about " if wiring is in metal
>conduit from roof to controls then no GFI is needed?  sounds good to me?
>
>later,
>
>jay
>peltz power
>
>Drake Chamberlin - Electrical Energy wrote:
>
> > Hi Jay,
> >
> > I don't know of any proposed changes to the code with respect to the array
> > ground fault protection.  If the RE Lab can get funding, this is one of the
> > areas that we would like to do independent research on.
> >
> > Best regards,
> >
> > Drake
> >
> > At 07:17 PM 02/20/2001 -0800, you wrote:
> > >Hi Drake,
> > >
> > >I agree with you and so have most of the electricans that I have talked
> > >to.  Just
> > >doesn't seem to make electrical sense.  If it opened the circuit at 
> the array
> > >then sure, but like you said, now you have people on the roof to check
> > >equipment-- not good.  No the exsisting equipment doesn't work, its
> > >expensive and
> > >a pain.  I might point out that Both Trace and AEI have the GFI built into
> > >their
> > >batterless inverters, it makes it pretty easy.
> > >
> > >Any chance of getting it removed from the next code?  IS there any
> > >thinking along
> > >those lines.??
> > >
> > >later,
> > >
> > >jay
> > >
> > >Peltz Power
> > >
> > >Drake Chamberlin - Electrical Energy wrote:
> > >
> > > > Hi Wrenches,
> > > >
> > > > The new DC ground fault technology is certainly much better than 
> the old
> > > > Pulse systems.  But I still have a major problem with it.
> > > >
> > > > If the device is to protect the wood framing between the solar 
> modules and
> > > > the charge control, it needs to be mounted on the roof.  If the 
> wire were
> > > > to become shorted (for example with a nail through a cable) the current
> > > > would continue to circulate between the nail and the 
> array.  Heating could
> > > > result, especially with a large array.
> > > >
> > > > A roof mounted ground fault device would likely pose more danger to 
> home
> > > > owners who might climb on the roof to correct nuisance tripping than it
> > > > would eliminate danger from fire.  I suppose a device could be 
> developed
> > > > that would have a reset in the power room and ground fault 
> protection by
> > > > the array.
> > > >
> > > > I believe that better protection could be afforded by using armored 
> cable
> > > > or conduit to protect the circuit.
> > > >
> > > > Have there been any recorded fires from roof mounted arrays?  If there
> > > > really are fire hazards from roof mounted arrays, they should be 
> addressed
> > > > effectively.  I am skeptical about the effectiveness of the current
> > > > technology.
> > > >
> > > > I also doubt that a roof mounted array is as dangerous as a 240 volt
> > > > service drop coming from a pole, capable of delivering 10,000 
> amps.  There
> > > > seems to be a tendency to require RE installations to be 10 times safer
> > > > than grid connected systems.  Why is that?
> > > >
> > > > Drake
> > > >
> >
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