Subpanel location, mounting on the joist

Discussion in 'Electrical Forum discussion & Blog' started by electrotuko, Jan 31, 2014.

  1. electrotuko

    electrotuko New Member

    Messages:
    47
    Location:
    Chicago, IL
    I want to add a 60A subpanel, 4 spaces, 8 circuits, fill be fed by a cable running from the main panel to the crawl space. This will provide the slots for circuit breakers to power light fixtures, water heater circulation pump, whole house water filter, few receptacles - all in the crawl space which is 5 feet high.

    I was reading NEC 110.26 and did not find an answer if I can mount that small subpanel box on the 12†joist (part of the ceiling in the crawl).The subpanel will be located kind of between the joist, mounted of the surface of one of them. It is 4" spacing between the top of the panel and the plywood (forming a floor for the next house level).
    The required 3’ clearance is there, but not directly, the adjacent joist is 14.5†away from the one that subpanel is mounted, but it does not restrict the access to the panel inner electrical circuits/breakers. Is this is acceptable?
    It is no any other suitable surfaces in that crawl space to mount the box, only concrete walls, and the cables are stapled to the joist as well. So convenient to mount the panel right there.
  2. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,106
    Location:
    Houston, TX
    You want to mount a Subpanel in a crawl space ? Or did I miss understand.


    Good Luck.
  3. electrotuko

    electrotuko New Member

    Messages:
    47
    Location:
    Chicago, IL
    Yes, on the ceiling's joist. The crawl is kind of lower ceiling height basement, can I?
  4. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Huh?

    Are you suggesting mounting a panel on a ceiling? Not a chance.

    Is this a basement or a crawl space? With the second, no chance. Ceiling height and access will be critical.

    You gotta have at least 6', I'd guess. And it could be more.

    And if one needs to crawl thru a hole to get into the space, forget about it.

    If the walls are concrete or brick, mount some pressure treated 2x4s to the concrete and then mount the panel to that. That separates the steel electrified panel from a damp concrete wall. Which would be a good thing.

    And the floor must be concrete.

    I don't think this is going ot work for you. Why not have the new panel adjacent to the existing panel? The various items that you need to add can be down there, but not the panel, would be my view.
  5. electrotuko

    electrotuko New Member

    Messages:
    47
    Location:
    Chicago, IL
    Well, looks like that is very critical issue and I will need to comply with the Code.
    Thanks for your advise, will think about adding adjacent panel and run a number of cables down to the crawl.
    Thanks again for your valuable inputs.
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,534
    Location:
    North Carolina
    Let’s think about this a little. Can a panel be installed on the outside of a house, one like a meter main combo?
    Then maybe having a dirt floor doesn’t matter that much

    The main thing is the working space which must be at least 36 inched back from the front of the panel and at least 30 inches wide and have a head room of at least 6 ½ feet. 110.26(A)(1)(2)&(3)

    110.26(C) addresses the access to and egress from working space but does not say anything about getting to the working space. I suppose one could be required to climb stairs such as if the panel was installed on the second floor or even crawl around on ones hands and knees.


    Based on the information I came up with should you decide to dig out a place just a little bigger than outlined above I don’t see why you couldn’t make it work, If you decide to dig it out just a little bigger than the required working space and mount a board between the joist for the panel which has no minimum mounting height the 30 inches of within front of the panel would be easy to achieve. .

    Mike why did you keep saying just a little bigger than the required working space? I just thought it might be a good idea to have a sump pump in the hole that was dug out. Remember that any and the entire receptacle installed in the crawl space are required to be GFCI protected.
  7. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,534
    Location:
    North Carolina
    Nail a 2X4 to each joist and rip a ¾ inch ply board 14 ½ inch to nail to the 2X4 and mount the panel to a max height of the joist and be code compliant
  8. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,106
    Location:
    Houston, TX
    I would not do that even if code allowed it.
  9. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,534
    Location:
    North Carolina
    He was asking what was code compliant not what my opinion was. As long as he has the working space there is nothing code wise that says he can't.
  10. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,106
    Location:
    Houston, TX

    I understand that, I was not saying that you were wrong.

    You did a great job of explaining the Code.

    I do not agree with all of the minimal code requirements, I do what is safe for me and my family.

    And I do not have to answer to a Insurance company, or HOA.

    Being safe is my first concern, and do not need to be told what I can or can not do.


    I could be wrong, But that is how I roll.
  11. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Here in LA about 95% of the panels are exterior combo with meter design.

    And every jurisdiction that I work in insists that there be a concrete pad to stand on while working on the panel, thirty inches wide and thirty six inches deep.

    He needs 18" more headroom than indicated.

    I simply cannot imagine an inspector signing off on a panel mounted to the underside of a floor.

    Nor can I imagine him being OK with a panel that is only accessed by crawling into a space.

    Older houses around here have small "basements" excavated in them that are just large enough for the water heater and HVAC, with the rest of the house over a crawl space of 16" or so. These are accessed by a stairway and have a ceiling of 6' or so.

    I can imagine myself selling THAT to the inspector as a location for a small panel. But not with a dirt floor.

    Local authorities can have restrictions that are not found in the NEC, yes? And do not need to accept every element of the NEC, yes?

    No way I would put a panel on anything but a vertical surface, a wall. I think the supplemental panel should be right next to the existing panel.
  12. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,106
    Location:
    Houston, TX
    That is one reason, I would not live in LA.

    Another is water rations.

    Your code sucks.


    Sorry but true.
  13. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,534
    Location:
    North Carolina
    The size is the required working space about a panel that has a voltage of less than 150 volts to ground. The concrete must be a local requirement as the NEC will even allow a wooden platform for a panel such as a floor.

    This can be achieved by digging out the working space

    The reason for installing a board for mounting the panel.

    As long as the required working space is at the panel the access to that working space is not mention in the NEC. It can be by ramp, stairs, ladder should it be on a roof or even by crawling through an area to arrive at the working space.

    It will need at least 6.5 feet of head room but unless your area has adopted some requirement for concrete the dirt floor is no more than the dirt around the AC disconnect.

    Your area must have amended the fact that one must be standing on concrete but I don’t understand how this would affect a panel found on the second floor of a building.
    but cannot adopt any thing less than what the state has adopted at least here in NC

    What our opinion or our thoughts is in no way enforceable. As a code enforcement official all I can enforce is the adopted code and the code in no way forbids a panel in a crawl space if it has the require working space.
  14. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,106
    Location:
    Houston, TX
    Mike,

    Make sure you have your concrete pad when you go to LA to do inspections.

    Having a concrete pad will not happen here, Maybe a 12 inch stepping stone. You will need to bring your own thirty inches wide and thirty six inches deep slab, and your Gorilla to carry it for you.

    I do not see why a concrete pad makes anything safer. Unless you are standing in water. LA is out of water, It seems. The Ocean must be drying up. Hold on to your hats.

    Sounds like inspectors that do not want to get their shoes or hands dirty.


    I guess they want a person to buy them lunch too, on the way to the shoe shiner, and manicure shop.
    Last edited: Feb 1, 2014
  15. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,106
    Location:
    Houston, TX
    What is the code about having a Electric Break-Away, in LA ?

    They should be required by code in California for when it falls into the Ocean.

    Won't be much longer. They will have plenty of water then.

    Saltwater and electricity could be a hazard for residents when it happens. Saltwater can be very conductive.

    That Time may be coming sooner than you think.

    Why do you think they moved the Tonight Show to the east cost. ?


    Jay did not want his cars getting wet. He will have a Electric Break-Away on all of his car trailers when he heads east, as required by code.
    Last edited: Feb 1, 2014
  16. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    You don't like a Mediterranean climate where you can go about in shorts and a t-shirt more than 11 months per year?

    I've lived in frosty climates. Thanks, you can keep them.

    I'm just telling you that dirt is not acceptable as a work surface in front of an exterior panel. And likely not a basement panel.

    And no, JW, obviously a panel on the second floor is not covered by such a requirement. Only the access restrictions and not being in a closet, of course.
  17. electrotuko

    electrotuko New Member

    Messages:
    47
    Location:
    Chicago, IL
    Thanks everyone for clarifying, I got the point. Even thought it would be possible to comply with the NEC and make it as jwelectric pointed, but I would have to agree, it would look clutch/not clear. I will be running seven individual NM-B or 3/8" metal flex. Can I run seven NM-Bs as a bundle? Using plastic tier wrap and hang them on a metal hooks attached to each joist (running across multiple joist). Or I have to run them in parallel stapling each individually to joists (that would be exhausting to make in the crawl)?
    At least I can run multiple 3/8" metal flex's in a bundle, hanging on the - let's say metal holders (clamps) made for EMT pipes?
  18. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    No, you cannot deliberately bundle NM that way, it causes induction heating. The best thing is to create a "nailer" that allows them about an inch separation. There are also products for supporting NM cable when run in a wall and hung from a stud.

    Typically it is a plastic device that has a nail to hold it to the stud, and four or five clips that will grasp the NM.

    http://www.cyberguys.com/product-de...8&sk=MC71419&gclid=CIfZg_WjrLwCFTHZQgodfUEAYQ

    Home Despot has them in smaller quantities.
  19. Bobelectric

    Bobelectric Electrical Contractor

    Messages:
    38
    Location:
    Eighty Four,Pa. 15330
    You're off to a bad start using mini breakers.
  20. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Fair point. No reason to not buy as many spaces or more than you need for circuits.
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