PV and the 2005 NEC -- Reference Document

crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
Here's a link to a recent (March 2007) John Wiles publication. This document looks to be quite useful, and it may save having to buy or borrow a hard copy of the entire NEC.

http://www.nmsu.edu/%7Etdi/Photovoltaics/Codes-Stds/PVnecSugPract.html

HTH,
Jim / crewzer

Comments

  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: PV and the 2005 NEC -- Reference Document

    nice link for everybody. maybe you should sticky this one.
    nevermind i made it stick.
  • VicVic Solar Expert Posts: 2,969 ✭✭✭✭
    Re: PV and the 2005 NEC -- Reference Document

    Hi Jim,

    Another very useful post from you. Thanks a lot ... amma dialer-up, so may need to wait til off time to DL this. Thanks again, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • System2System2 Posts: 6,290 admin
    Re: PV and the 2005 NEC -- Reference Document

    Thank you, Thank you, Thank you. Texas just passed laws bringing us under inspection requirements. Glad this system is grandfathered in.
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: PV and the 2005 NEC -- Reference Document

    Just a heads up, NEC 2008 is out, so some areas maybe using that.
  • rrbvrrbv Registered Users Posts: 15 ✭✭
    Re: PV and the 2005 NEC -- Reference Document

    For the past few years I’ve been hearing about how efficient and less expensive it is to install solar power systems in Germany. Many people credit this growth to their feed-in tariff. But at the end of the day, it’s really lower costs that will drive faster market growth.

    So I wondered, why are German installations so much less expensive than U.S. installations? Is it because of superior engineering, better beer or something else entirely.

    Well, there’s only one way to find out – and that’s from the roof down. So…after tromping all over the country with our Regional Director (who’s got more roof time than me – plus much safer driving skills) we learned that fundamentally, costs are lower in Germany because there are fewer system requirements and regulations.

    - Negligible incentive paperwork (job folders are 2” thick in the U.S.)
    - No engineering drawings (installers work off diagrams)
    - No local building permit
    - No local inspection
    - No utility interconnection paperwork
    - No utility inspection
    - No rebate “check is in the mail”
    - No AC disconnect
    - No DC disconnect
    - Source circuits from modules are run with USE-2 cable with quick connects right into sockets on the inverters – no wire transistions
    - Source circuit cabling runs in snap-on plastic raceway – no conduit
    - There are residential solar installers with storefronts in many towns
    - Jobs are done in a week – from start to finish, including paperwork
    - Oh, and by the way, no grounding is required on each module and rack component.

    So before anyone here in the U.S. advocates that feed-in tariffs will result in a market that grows as fast as Germany, we must first recognize that our costs are structurally $1-$2 higher. Regardless of how much more efficient our industry gets (and some companies already run a very tight ship here), we cannot make these additional costs disappear easily. Note that many of these additional costs are fixed, so on larger systems they are not as significant. On smaller residential systems incentives must be designed to take this substantial “bureaucratic friction” into account.
  • emo69emo69 Registered Users Posts: 9
    Re: PV and the 2005 NEC -- Reference Document

    :cool:good post. i guess i'll be waiting on the price to come down further, it has to sooner or later. there sure is a lot of over priced stuff out there thats for sure. if a person was to use the micro inverter set up and do the install himself he could pay as you go and not go bankrupt all at once. as for me it's cheeper to read about solar than jump in over my head.:confused:
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: PV and the 2005 NEC -- Reference Document

    making solar more affordable is always a good thing, but if you are waiting for that really cheap price to come about, then it will never materialize as prices this year have fallen quite a bit. also the governmental incentives for the states and local levels, if and where applicable, seem to be less incentive and more red tape and waiting, which is typical government.
  • emo69emo69 Registered Users Posts: 9
    Re: PV and the 2005 NEC -- Reference Document

    :Governmental incentives are what I’m looking for. You’re right more red tape and waiting that’s what you’re government does best. When they hand out the money you just need to figure out how to get it. That’s what I need help with.
    I would even let NAWS put their name on a sign out front of my house if it would save me money. . It’s like Computers, TV’s and Electronics the price will drop when someone perfects the process further.

    I went to my REMC’s meeting for people interested in alternative energy. Wind was the topic but it sounds like too much maintenance. I think the Enphase micro-inverters setup is the ticket. You could put together a smaller size system one panel at a time.
    :roll:
  • WindsunWindsun Solar Expert Posts: 1,164 ✭✭
    Re: PV and the 2005 NEC -- Reference Document
    emo69 wrote: »
    :cool:good post. i guess i'll be waiting on the price to come down further, it has to sooner or later. there sure is a lot of over priced stuff out there thats for sure. if a person was to use the micro inverter set up and do the install himself he could pay as you go and not go bankrupt all at once. as for me it's cheeper to read about solar than jump in over my head.:confused:

    I doubt that the price will drop much more in the near future. And even though most panel prices have dropped quite a bit over the past year, other prices - such as inverters and batteries have not, or in some cases have gone up.

    Updated info on NEC changes can usually be found here http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/C-S-Resources.html
  • cpetkucpetku Registered Users Posts: 22
    Re: PV and the 2005 NEC -- Reference Document
    crewzer wrote: »
    Here's a link to a recent (March 2007) John Wiles publication. This document looks to be quite useful, and it may save having to buy or borrow a hard copy of the entire NEC.


    Be careful on this. I've seen documents dated as far back as 2006 stating that you can run AC and DC for a single solar system in the same raceway, but this seems to be from the 2011 NEC 690. I pushed the local AHJ on this but lost as they said it was not allowed in the 2005 or 2008 NEC/690.

    It would have been nice to avoid a seperate conduit all the way into the inverter for the DC since I had a box channel installed to clean up the installation. Ultimately it's the AHJ's call on "recommended practices".

    Also note that in some jurisdictions (like mine) they are still using the 2006 electrical code which allows for replacing the main panel without updating all the breakers to arc faults. If you are considering this to increase the bus bar ratings try to get it in under the 2006 code to save a lot of $$$ as my AHJ told me the 2008 NEC requires all breakers be ARC Fault protected. We adopt the 2008 NEC in about three months.
  • SevenSeven Solar Expert Posts: 292 ✭✭
    Re: PV and the 2005 NEC -- Reference Document

    Is the link in the first post still revelant? I had some questions about locations of things and was looking for a NEC reference and this is the one I found.

    I just want to make sure that the info contained is correct. The link is still good and has an appendix from april 2010
  • SevenSeven Solar Expert Posts: 292 ✭✭
    Re: PV and the 2005 NEC -- Reference Document

    The NEC in Section 690.14 requires that the main PV disconnect be in a similar
    location. It therefore must be in a readily accessible location (no bathrooms, no
    attics—unless served by a permanent fixed stairs) at the point of first penetration
    of the dc PV source or output conductors. As in the ac service entrance
    disconnect, this PV disconnect may be located immediately inside the point of
    first penetration of the conductors. If the attic is reached by fixed stairs (not pull
    down), then the disconnect might be mounted in that location. Disconnects in
    bathrooms are not allowed. Other readily accessible rooms are acceptable as long
    as there are no locked doors.
    Although commonly done in the past, many inspectors are not allowing PV
    conductors from the roof-mounted PV array to penetrate the attic and be run
    through the walls to the first floor or the basement where the main PV disconnect
    is located. These “always energized” conductors pose hazards to fire response
    personnel and possibly a fire hazard since they are in locations where potential
    short circuits might start fires.
    The 2005 NEC allows an inside circuit installation provided it meets certain
    additional requirements. If the conductors are installed in a metal conduit or
    raceway, they will be permitted (not required) to be routed inside the house to the
    dc disconnect located at some distance from the point of first penetration. The
    disconnect will still have to be readily accessible, but this allowance, if adopted,
    will permit more design and installation flexibility. The metal conduit/raceway
    provides for added fire protection (does not burn), mechanical protection (difficult
    to accidentally cut), and ground-fault detection (in the event there is an internal
    ground fault). [690.31(E)]

    If I am understanding that correctly, I can run my wires from the panels on my roof through conduit to a PV disconnect in my garage. Is that correct?
  • rollandelliottrollandelliott Solar Expert Posts: 755 ✭✭
    Re: PV and the 2005 NEC -- Reference Document

    sure it's correct if your local codes inforcement agrees with that, best to ask them.
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