Can Inverter be inside the home/garage?

aj164aj164 Solar Expert Posts: 122 ✭✭✭
OK. The utility does not want inverters mounted inside of a building. I see examples of indoor mounting (garage, lofts, mechanical rooms, etc.) all over the place!

I normally put them outside, but some people don't want excess equipment hanging on their brand-new brick or stone siding.

I need hard proof that indoor mounting is not unsafe. I thought the NEC would help with 690.14(D), "Inverters mounted in not readily accessible locations", but it specifically says "...mounted on roofs or other _exterior_ areas not readily accessible..."

Presumably, inverters that are mounted in readily-accessible locations can be indoors, but I have not found those magic words in the NEC. John Wiles' various articles say 'readily-accessible' and 'no bathrooms'.

Any ideas or other references?

Thanks again!
-AJB

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Can Inverter be inside the home/garage?

    they don't want them in a building and don't consider inside to be accessable? who do they want them accessable for or to? this isn't wiring, but it is electronics and should be inside imho due to operating parameters for them like temps in summer and winter adversely affecting operations at times and the dangers of moisture to them. they don't insist on your circuit breaker box for the home to be outside in order to be "accessable". imo, they're jerking you around.
    get a small doghouse and put the inverter inside of it. satisfies them and thieves won't want to find out if there's a dog or not.
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    Re: Can Inverter be inside the home/garage?

    They likley want to be able to get to the OFF switch, so an AC disconnect outside next to your meter may be the ticket.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • RoderickRoderick Solar Expert Posts: 253 ✭✭
    Re: Can Inverter be inside the home/garage?

    Hopefully you can speak with a live person at your electric company, and cordially discuss what they are really concerned about. It could be that they just want a disconnect switch outside, near the service panel.

    I will confirm that having the inverter in the garage is quite common. I've never seen one inside the living area, for some reason. Maybe it's ugly, or the hum is objectionable.
  • BB.BB. Super Moderators, Administrators Posts: 32,609 admin
    Re: Can Inverter be inside the home/garage?

    My GT 3.0 is also in my garage... I believe the latest requirements for California don't require a separate AC disconnect near the meter--Since the Inverters take care of determining when it is safe to generate power, there is no reason for a manual disconnect.

    But when mine was installed--there was still that requirement and we just ran a 10' piece of conduit from the inverter, through the wall, to near the meter (and wired back to the breaker panel) with a simple knife switch.

    Our PG&E worker did not even take two seconds to review the installation--just checked for a signed building permit label on the meter box, and swapped out for the new Time Of Use meter...

    In someways--I was not thrilled with the external disconnect requirement... I have a box with 240 VAC and an exposed knife switch right at small kid level (enclosure is a simple swing up--have to install a pad lock or nut and bolt to "lock" and prevent access).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • aj164aj164 Solar Expert Posts: 122 ✭✭✭
    Re: Can Inverter be inside the home/garage?

    The utility knows nothing about PV and is quite frightened of it. They've hired an private inspector (pun intended) as a consultant to travel here to do PV inspections. This guy inspects according to mid 90's convention (or earlier). He told me I could not run DC through the building, at least not without a disconnect at the point where it enters the building. He told me my Ferraz-Shawmut fuseholders were unsafe; that the fuse would be energized because "one end was still in the holder in the open position". I asked him why, then, are they called Touchsafe? He then took out the multimeter to try and prove me wrong (to no avail). He said I cannot use wire nuts on DC connections. I told him you can use wire nuts if it's over 50V and the wire nuts don't specify "AC". He then produced a copy of "PV and the NEC" from his truck and suggested I study up on it. (That's where I got the wire nut info in the first place...)

    On the roof, he said I must move my roof penetration, because it cannot be located under the array/module due to accessibility. Maybe I misunderstood the NEC:

    690.34 Access to Boxes
    “Junction, pull, and outlet boxes located behind modules or panels shall be so installed that the wiring contained in them can be rendered accessible directly or by displacement of a module(s) or panel(s) secured by removable fasteners and connected by a flexible wiring system.”

    This guy is a total disaster, and the utility company trusts him b/c there's no alternative. He later told the utility I need more education and experience before I install another system. We desperately need an inspector here that has at least bothered to read NEC 2005.

    FWIW, this system is 3.2kW, 18 BP 175B modules on Unirac rails. Footings are 3/8" x 4" ss lag bolts sealed with a 2" epdm-bonded ss washer against a 12"x12" 1/16" aluminum plate (used for flashing) with M-1 sealant in the hole, under the washer, and on top of the L-foot slotted bolt hole. I have two strings of nine modules. Each string a separate run to the inverter with #10 THHN in heavy 1" FMC, clamped along a joist in the attic below foot traffic level all the way to the DC disconnect. The disconnect is the monster 3-pole HU361 (completely redundant and unnecessary) with Touchsafe 600VDC-rated fuses inside. The module frames are bonded with Ilsco tinned copper lay-in lugs, bolted to the frames with #10 ss screws and a ss kep nut (nut w/ star washer). #6 bare copper traverses the entire array through each ground lug and two additional lugs bolted to each rail at the ends.

    #12/3 Romex takes the AC from the inverter to a 20A breaker in my PV subpanel. Then, #8/3 NM cable (stranded w/ gnd) goes from the subpanel to a 60A AC disconnect, PV meter (utility-required), and finally a 40A breaker in the main service panel. The disconnect and meter are located on an exterior wall within a couple of feet of the service entrance, main utility electric meter, and main breaker panel. I have labels on everything, laser-printed on heavy stock and laminated, including a one-line diagram/map on the main breaker panel showing the location of the DC disconnect and inverter.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Re: Can Inverter be inside the home/garage?

    The only suggestion I have is to request that any issues be in writing and have the NEC code reference. Then You can take the NEC2005 or NEC2008 and quote why its OK.

    You install sounds like its meeting NEC from your description ...

    Don't lose your cool, your going to have to work thru the concerns, just stick to facts and make any communication written so you can have clear, non-emotional responses

    If you don't have a copy, get the NEC book, best money you will ever spend
  • BB.BB. Super Moderators, Administrators Posts: 32,609 admin
    Re: Can Inverter be inside the home/garage?

    To a large degree--the utility should not care about the "DC" side of your system...

    There is a big "black box" (your inverter) that is UL/NRTL listed to be used in your application.

    This would be as bad as if the utility was inspecting your dishwasher, electric water heater, and well pump installation with the same zeal...

    As far as I know--there is nothing on the DC side of the inverter that can cause problems for the utility. Gosh--even a lightning strike on your panels is no worse than a lightning strike on your utility drop into your home.

    The local city building department and your insurance company should care about your complying with NEC on the DC side of the installation (unless your utility is also part of your local city/county government).

    I am sorry to hear that you had such problems with the private inspector--normally the guys I would work with (UL/etc. inspectors for work, and building inspectors for home) would work with us pretty well... Pull out the regulations (NEC, UL specs., etc.) and figure out the intent of the regulation and what was the best end result.

    But, why would a Utility Inspector care about your DC use of wire nuts, etc.? Sounds more like the city/county inspectors.... :confused:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Can Inverter be inside the home/garage?

    "But, why would a Utility Inspector care about your DC use of wire nuts, etc.? Sounds more like the city/county inspectors.... :confused:"

    actually this is worse than a city/county inspector because this utility does not want pv connected at all and is willing to do anything it seems to prevent or circumvent its placement within their utility jurisdiction. if he had a local inspector he may be able to put him into his favor to fight the utility by having somebody of authority saying it to be nec compliant. you may need to review your state's requirements when dealing with utilities allowing/disallowing pv usage and possibly an attorney as now your are fighting a large powerful conglomerate.
    in the meantime take the advice by sg and see if it pans in your favor and it is important to have something in writing to fight them with anyway. it may also be a good idea to get a good electrician to give his advice and viewpoints on the matter as they probably deal with these idiots all of the time. he may not fight for you though because he has to deal with these idiots all of the time and would not want to cut his own throat.
  • autoxsteveautoxsteve Solar Expert Posts: 114 ✭✭✭✭
    Re: Can Inverter be inside the home/garage?

    all of my equipment is in my garage other than the electric meter.
  • aj164aj164 Solar Expert Posts: 122 ✭✭✭
    Re: Can Inverter be inside the home/garage?

    Problem is solved. The utility now agrees that indoors is okay. Thanks for the help!
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Can Inverter be inside the home/garage?

    no problem, but what changed their minds out of curiousity?
  • aj164aj164 Solar Expert Posts: 122 ✭✭✭
    Re: Can Inverter be inside the home/garage?
    niel wrote: »
    no problem, but what changed their minds out of curiousity?

    Part of my presentation included many examples of inverters mounted indoors. I talked about and showed pictures of the sophisticated electronics inside and the temperature sensitivity. I pointed to the owners manual, which shows that it could start to derate as 'low' as 104F. Temps go to 104 here easily. Indoors, at least it would be shaded and protected from excess moisture. Aside from all this, however, they had been doing their own research and came to the same conclusions before the meeting.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Can Inverter be inside the home/garage?

    i congratulate you as you are smarter than your inspector as he's just learning and you taught him. imagine that?:roll:
  • RoderickRoderick Solar Expert Posts: 253 ✭✭
    Re: Can Inverter be inside the home/garage?

    I also congratulate you on your diplomacy. If you had escalated this into a war, it might not have gone so well.
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