interior DC runs [RE-wrenches]

Peter Parrish peter.parrish at calsolareng.com
Sat Dec 17 10:25:25 PST 2005


Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Is your computer freezing up or slowing down?
Repair corrupt files and harmful errors - protect your PC
Take a 2-minute PC health check-up at no charge!
http://click.topica.com/caaegt3bz8Qcsbz9JC9a/PC PowerScan
-------------------------------------------------------------------

Conrad, I forgot one piece of the puzzle and misspoke on one other. 

The mistake: for the purposes of "fault analysis" the ampacity of the PV
module is the module's series fuse rating if the modules have fuses, not
Isc.

The forgotten piece: Backfeed from the inverters is a theoretical problem
and needs to be included in your calculation. However, SMA claims that the
2500U includes electronic current limiting preventing reverse current flow
into the PV array, and cites that this feature has been verified by testing.
I think that you can get a letter from SMA to this effect. I don't know
about the other inverter manufacturers.

- Peter

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave.
Los Angeles, CA 90065
Ph 323-258-8883
Mobile 323-839-6108
Fax 323-258-8885
peter.parrish at calsolareng.com 


-----Original Message-----
From: Peter Parrish [mailto:peter.parrish at calsolareng.com] 
Sent: Thursday, December 15, 2005 5:21 PM
To: RE-wrenches at topica.com
Subject: RE: interior DC runs [RE-wrenches]

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Is your computer freezing up or slowing down?
Repair corrupt files and harmful errors - protect your PC
Take a 2-minute PC health check-up at no charge!
http://click.topica.com/caaegt3bz8QcsciXpi6a/PC PowerScan
-------------------------------------------------------------------

Conrad:

I posted a similar query and got some helpful information but the rest of it
I found out the hard way. Here is a distillation of what I learned.

The DC disconnect must be on the _outside_ of the building shell. It does
not need to be current limited as PV modules have a finite output (Isc), and
all you should have to do is demonstrate that the ampacity of the DC wiring
is adequate (1.56*Isc and derated for temperature appropriate for the DC
run). Nonetheless most jurisdictions require current limiting, so get a
600VDC rated fusible disconnect with the right fuses (which I assume that
you can specify) and you should be covered. You spend another $40 for the
fusible disconnect, but it probably saves hours of painful review of the NEC
handbook with a testy inspector -- your choice.

The inside run should be in metal flex and protected by plates where they go
through studs. Some folks tag the flex "600 VDC Solar Generator" or the
like.

- Peter 

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave.
Los Angeles, CA 90065
Ph 323-258-8883
Mobile 323-839-6108
Fax 323-258-8885
peter.parrish at calsolareng.com 

-----Original Message-----
From: Conrad Geyser [mailto:conradg at cape.com] 
Sent: Thursday, December 15, 2005 4:06 AM
To: RE-wrenches at topica.com
Subject: interior DC runs [RE-wrenches]

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Save up to $1,500 on your phone bill with Packet8
Free Activation, Free Equipment & First Month Free!
30-day money back guarantee. 1-877-868-1135
http://click.topica.com/caaegt4bz8QcsciXpi6a/ TMONE
-------------------------------------------------------------------

Hi all,
We've got a few installations where we'd like to run the feed from the
panels to the inverter inside the building.  Even with a DC shutoff just
inside and metal conduit, the inspector isn't buying it.  Any suggestions?
Conrad
Cotuit Solar
----- Original Message ----- 
From: "Max Balchowsky" <max at seesolar.com>
To: <RE-wrenches at topica.com>
Sent: Thursday, December 15, 2005 6:36 AM
Subject: RE: Top of pole internal wiring [RE-wrenches]


> Your free subscription is supported by today's sponsor:
> -------------------------------------------------------------------
> Save up to $1,500 on your phone bill with Packet8
> Free Activation, Free Equipment & First Month Free!
> 30-day money back guarantee. 1-877-868-1135
> http://click.topica.com/caaegt4bz8QcscfnEoDa/ TMONE
> -------------------------------------------------------------------
>
> Gary, we did traffic signal and street lighting for years (lots of pole
> mounted stuff), Some of the pole manufacturers will have options to point
> you too for brackets to mate a flat box to a round pole surface. People
like
> Econolite will also equipment to do this efficiently, keeping every thing
> clean. They have many options you can order with terminal strips already
> installed if you so desire..... There's lotsa of stuff out there to do
that,
> if you want to come out of the very top - they have top caps that come pre
> drilled or that can be drilled....
> Call me direct if you need any more info.
>
> Max Balchowsky
> SEE Systems
> 100 S. Sunrise Wy # 285
> Palm springs, Ca. 92262
> Phone - 760-403-6810
> Fax -     760-406-4230
> www.seesolar.com
>
> -----Original Message-----
> From: Gary Higbee [mailto:gary at windstreamsolar.com]
> Sent: Tuesday, December 13, 2005 5:00 PM
> To: RE-wrenches at topica.com
> Subject: Top of pole internal wiring [RE-wrenches]
>
> Your free subscription is supported by today's sponsor:
> -------------------------------------------------------------------
> Is your computer freezing up or slowing down?
> Repair corrupt files and harmful errors - protect your PC
> Take a 2-minute PC health check-up at no charge!
> http://click.topica.com/caaegt3bz8Qcsa96hbMa/PC PowerScan
> -------------------------------------------------------------------
>
> Wrenches,
>
> What is the best way to exit wires from inside a top of pole PV mount?
I've
> got a park project, and they don't want a conduit run up the side of the
> pole (concerns someone will break it--this is a vandalism-prone area).
We'll
>
> have three runs of #6 coming up the inside of a 6" schedule 80 pole. The
> 7/8" hole in the DP&W TOP mount will only take a 1/2" fitting, but we need
> 1" conduit for the three #6's. If we drill a hole through the pole wall we
> can't use nonmetallic flex out the side, because the bend radius is too
> small.
>
> We'll be combining two strings of four Unisolar ES-62's in a J-box up
there.
>
> What's the best way to get from the inside of the pole to the box?
>
> Thoughts?
>
> Thank you!
>
> Gary
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>                      ~ Windstream Solar ~
>      Gary Higbee  (gary at windstreamsolar.com)
>                      (541 ) 607-1818 (Eugene)
>                         (541) 954-3881 (Cell)
> Solar, wind, and hydro site analysis and system design
>     Components dealer and installation management
>  Energy Trust of Oregon contracted system inspector
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Your free subscription is supported by today's sponsor:
> -------------------------------------------------------------------
> Make phone calls with phone service from Packet8.Order VoIP
> today & get Free Activation, Free Equipment & First Month
> Free! Packet8 30-day money back guarantee. 1-877-868-1135
> http://click.topica.com/caaegt4bz8Qcsa96hbMf/ TMONE
> -------------------------------------------------------------------
>
> - - - -
> 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/
>
> Hosted by Home Power magazine
>
> Moderator: michael.welch at homepower.com
>
> Your free subscription is supported by today's sponsor:
> -------------------------------------------------------------------
> Is your computer freezing up or slowing down?
> Repair corrupt files and harmful errors - protect your PC
> Take a 2-minute PC health check-up at no charge!
> http://click.topica.com/caaegt3bz8QcscfnEoDf/PC PowerScan
> -------------------------------------------------------------------
>
> - - - -
> 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/
>
> Hosted by Home Power magazine
>
> Moderator: michael.welch at homepower.com
>
>
>
>
>
>
>

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Is your computer freezing up or slowing down?
Repair corrupt files and harmful errors - protect your PC
Take a 2-minute PC health check-up at no charge!
http://click.topica.com/caaegt3bz8QcsciXpi6f/PC PowerScan
-------------------------------------------------------------------

- - - -
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/

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Save up to $1,500 on your phone bill with Packet8
Free Activation, Free Equipment & First Month Free!
30-day money back guarantee. 1-877-868-1135
http://click.topica.com/caaegt4bz8QcsciXpi6f/ TMONE
-------------------------------------------------------------------

- - - -
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/

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Save up to $1,500 on your phone bill with Packet8
Free Activation, Free Equipment & First Month Free!
30-day money back guarantee. 1-877-868-1135
http://click.topica.com/caaegt4bz8Qcsbz9JC9f/ TMONE
-------------------------------------------------------------------

- - - -
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/

Hosted by Home Power magazine

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

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
--^----------------------------------------------------------------

















More information about the RE-wrenches mailing list