Fieldlines.com || Comments Battery cable guage

Front Page - [Homebrewed Electricity-- (wind) (solar) (hydro) (steam) (controls) (storage) (mechanical)] - Classifieds - Site News
Everything - Newbies - [Remote Living-- (housing) (heat) (light) (water)] - Reviews - Diaries - Our Products

Battery cable guage | 10 comments (10 topical)

Re: Battery cable guage (3.00 / 0) (#5)
by richhagen on Fri Oct 30, 2009 at 03:56:30 PM MST

I think it was Stephen Fahey (Sparweb) who posted a link to the NEC guidelines for solar installations. I printed it out and have it at home, but don't have it handy at the moment. If you were to use 2/0 wire for the battery interconnects, then I think you would be required to fuse them accordingly as well. I would likely opt for 4/0 all the way even though it is a pain to work with and the costs are significantly more. That way I could just fuse the positive ends of cables from the bank to the inverter with a fuse rated for up to 4/0, about 250 Amps which should be fine for exposed THHN copper cable, and have a breaker at the DR3624 of about a 175 to 200 amps at the inverter, although I would definitely double check all of this before I did so. I would also fuse any other cables from the battery bank at a rating appropriate for the cables size. Rich
'A Joule saved is a Joule made'

Re: Battery cable guage (3.00 / 0) (#6)
by Volvo farmer on Fri Oct 30, 2009 at 05:21:03 PM MST

My system was installed by a professional, to 2006 NEC code, and passed local inspection. There are no fuses other than a 250A breaker before the inverter in the DC distribution box, and of course all the charging sources and controllers have appropriate sized breakers.

Either something has changed in three years, or my installer and inspector missed something, or there are no fuse requirements in the battery box itself.

I'd be interested to see that link to the NEC code if anyone finds it.

Volvo Farmer

[ Parent ]

Re: Battery cable guage (3.00 / 0) (#7)
by FishbonzWV on Fri Oct 30, 2009 at 05:57:25 PM MST

http://photovoltaics.sandia.gov/docs/PDF/checkcdcrnr.pdf

[ Parent ]

Re: Battery cable guage (3.00 / 0) (#8)
by dnix71 on Fri Oct 30, 2009 at 06:49:12 PM MST

There were changes in the 2008 NEC relating to solar. If you did your install earlier, then they didn't apply then.

Send me an email. dnix71 yahoo. I have the current NEC in pdf form if you want it.

[ Parent ]

Re: Battery cable guage (3.00 / 0) (#9)
by Dave B on Fri Oct 30, 2009 at 11:46:42 PM MST

Wow,

What a great response, thank you. More searching seems to prove out that 2/0 is fine for the interconnects but 4/0 is required for the battery to inverter and disconnect. I'm going to check with local suppliers just to get an idea on costs. Who knows, maybe pre-made will be the best. Anyone who has purchased battery supplies from a particular company with good service and reasonable pricing I would sure appreciate the contact information. Thank you again to all, Bonz (you've got mail) Dave B.

[ Parent ]

Re: Battery cable guage (3.00 / 0) (#10)
by hydrosun on Sat Oct 31, 2009 at 11:34:46 AM MST

I know in the past people would use welding wire and make ends with copper pipe crimped and soldered and flattened and drilled. I've got a big crimping tool and get cast copper lugs. The soldered lugs are probably better.
Chris

[ Parent ]

Battery cable guage | 10 comments (10 topical)

Menu

· create account
· How to use the board
· FAQs
· search the board
· Google search the board

Login

Make a new account

Username:

Password:

You must be a registered user to post here. It's easy and free, and the link is on the upper right side of your page.
All trademarks and copyrights on this page are owned by their respective companies. Postings are owned by the poster, but may be deleted or moved at the ADMIN's sole discretion. The Rest © 2009 Forcefield.
You can Email the board ADMIN here. PLEASE include the username you signed up with!