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Thread: Dedicated Electrical Space above equipment

  1. #11
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    OK, kwired. I see how we are appearing to disagree with each other. But we are not. This is one of those famous arguments that goes like this:
    Person 1 says, "The grass is green."
    Person 2 says, "No, you are wrong. The sky is blue."

    So let me revise my earlier post to clarify (revised wording is in bold, red text):

    • If the structural ceiling is less than 6 feet above the top of the panel, then no ducts or pipes can be between the top of the panel and the bottom of the structural ceiling.
    • If the structural ceiling is more than 6 feet above the top of the panel, then a duct or pipe can be run over the panel, so long as it is more than 6 feet above the top of the panel, and so long as you install a drip shield.


    Charles E. Beck, P.E., Seattle
    Comments based on 2017 NEC unless otherwise noted.

  2. #12
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    Quote Originally Posted by kwired View Post

    Structural ceiling is the bottom of joists or trusses above you on the level of the building you are on. A foreign system can run in the space above the structural ceiling even if the equipment requiring dedicated space is right up to the structural ceiling. Might not be a good idea design wise but is NEC compliant.

    .....

    Exception that follows allows suspended ceilings with removable panels in said zone but they are not part of the structural ceiling, so the dedicated space extends past a suspended ceiling.
    Concerning the definition of a "structural ceiling", suppose you have a 8 ft from the finished floor to the bottom of the joists for the next higher storey, and the joists are 2 ft tall. On top of the joists, is the corrugated steel decking and slab for the next floor. The space between the joists is open.

    Where is the structural ceiling in this room? Is it 8 ft above the floor, or 10 ft above the floor? Could you run foreign systems through the open joists, above equipment that requires dedicated space?

    If the joists are open, I'd consider the decking to be the structural ceiling. If there is a drywall ceiling below the joists, directly attached to the bottom of the joists, I'd consider that drywall to be the structural ceiling

  3. #13
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    Quote Originally Posted by Carultch View Post
    Concerning the definition of a "structural ceiling", suppose you have a 8 ft from the finished floor to the bottom of the joists for the next higher storey, and the joists are 2 ft tall. On top of the joists, is the corrugated steel decking and slab for the next floor. The space between the joists is open.

    Where is the structural ceiling in this room? Is it 8 ft above the floor, or 10 ft above the floor? Could you run foreign systems through the open joists, above equipment that requires dedicated space?

    If the joists are open, I'd consider the decking to be the structural ceiling. If there is a drywall ceiling below the joists, directly attached to the bottom of the joists, I'd consider that drywall to be the structural ceiling
    Structural ceiling is 8 feet above the floor IMO. Dedicated space on the next floor would start at floor level on that next floor - you have two feet of space between floors that is not dedicated space should there be electrical equipment directly above on the next floor, but sure would be nice if you have a feed through situatiuon that they leave you room to do so.

  4. #14
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    Quote Originally Posted by charlie b View Post
    OK, kwired. I see how we are appearing to disagree with each other. But we are not. This is one of those famous arguments that goes like this:
    Person 1 says, "The grass is green."
    Person 2 says, "No, you are wrong. The sky is blue."

    I like that argument! :P

    just to add on to my original questions:

    1) Suppose you had ductwork 2 feet above the panel. that's obviously a violation. Would encasing the ductwork in sheetrock help, or are you still in violation?
    2) What if you had a soffit or gypsum board ceiling 2 feet above the panel? is this a violation? the code says the ceiling, if less than 6 feet above, has to be a dropped or suspended ceiling. so if it's a solid ceiling, is it a violation?

  5. #15
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    Quote Originally Posted by Grouch1980 View Post
    I like that argument! :P

    just to add on to my original questions:

    1) Suppose you had ductwork 2 feet above the panel. that's obviously a violation. Would encasing the ductwork in sheetrock help, or are you still in violation?
    2) What if you had a soffit or gypsum board ceiling 2 feet above the panel? is this a violation? the code says the ceiling, if less than 6 feet above, has to be a dropped or suspended ceiling. so if it's a solid ceiling, is it a violation?
    1) Encasing it will not help, since the soffit is not a structural ceiling. It occupies space that might later be needed for electrical purposes.
    2) If it is a dropped or suspended ceiling, the space above it is still available for electrical purposes. If it is a solid ceiling but not the structural ceiling, the space is not available, but there is space there. No good. If the structural ceiling is less than 6' above the panel, does that mean the panel cannot be there? I think not.

  6. #16
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    Quote Originally Posted by charlie b View Post
    OK, kwired. I see how we are appearing to disagree with each other. But we are not. This is one of those famous arguments that goes like this:
    Person 1 says, "The grass is green."
    Person 2 says, "No, you are wrong. The sky is blue."

    So let me revise my earlier post to clarify (revised wording is in bold, red text):

    • If the structural ceiling is less than 6 feet above the top of the panel, then no ducts or pipes can be between the top of the panel and the bottom of the structural ceiling.
    • If the structural ceiling is more than 6 feet above the top of the panel, then a duct or pipe can be run over the panel, so long as it is more than 6 feet above the top of the panel, and so long as you install a drip shield.


    You are a better man than me. I couldn't even find where he said anything you didn't. What you said made perfect sense and what he said was a more convoluted and wordy example of the same thing. In this area where our inspectors are ridiculously over the top tough, they for some reason allow a building to install a 1 hour rated ceiling under the foreign system and determine that it meets code. I guess they have decided that a 1 hour ceiling is a structural ceiling. The fact is, I haven't found a valid legal description of "structural ceiling" in either the NEC of the Building code, so...........


    I know what I don't know, and I know where to go to find it!

  7. #17
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    Quote Originally Posted by GoldDigger View Post
    1) Encasing it will not help, since the soffit is not a structural ceiling. It occupies space that might later be needed for electrical purposes.
    2) If it is a dropped or suspended ceiling, the space above it is still available for electrical purposes. If it is a solid ceiling but not the structural ceiling, the space is not available, but there is space there. No good. If the structural ceiling is less than 6' above the panel, does that mean the panel cannot be there? I think not.

    I posted a posit below, and not to be argumentative, because I believe it is not a structural ceiling, but can you provide me with a legal building definition of a structural ceiling? What about a mezzanine is that a structural ceiling? What if the mezzanine is only 2 feet wide?


    I know what I don't know, and I know where to go to find it!

  8. #18
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    Quote Originally Posted by GoldDigger View Post
    1) Encasing it will not help, since the soffit is not a structural ceiling. It occupies space that might later be needed for electrical purposes.
    2) If it is a dropped or suspended ceiling, the space above it is still available for electrical purposes. If it is a solid ceiling but not the structural ceiling, the space is not available, but there is space there. No good. If the structural ceiling is less than 6' above the panel, does that mean the panel cannot be there? I think not.
    I agree with your answer for my 2nd question... however, when is that ever seen? you will always see a solid ceiling a few feet above the panel... never will you see it above the 6 foot requirement.

  9. #19
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    Quote Originally Posted by charlie b View Post
    The way you worded this has me confused over what you intended to say. So let me say it this way:
    • If the structural ceiling is less than 6 feet above the top of the panel, then no ducts or pipes can be above the panel.
    • If the structural ceiling is more than 6 feet above the top of the panel, then a duct or pipe can be run over the panel, so long as it is more than 6 feet above the top of the panel, and so long as you install a drip shield.


    Is that what you were trying to say?

    Quote Originally Posted by Strathead View Post
    You are a better man than me. I couldn't even find where he said anything you didn't. What you said made perfect sense and what he said was a more convoluted and wordy example of the same thing. In this area where our inspectors are ridiculously over the top tough, they for some reason allow a building to install a 1 hour rated ceiling under the foreign system and determine that it meets code. I guess they have decided that a 1 hour ceiling is a structural ceiling. The fact is, I haven't found a valid legal description of "structural ceiling" in either the NEC of the Building code, so...........
    The part I bolded in above quote is what I disagreed with and I did not (intend to, if that is how it was interpreted)say the same thing as that says.

    If the structural ceiling is less than 6 feet above the top of the panel, then ducts or pipes can be above the panel, if they are also above the structural ceiling.

    You maybe have a reasonable argument on what is a structural ceiling though. I think most will agree though if a part of the structure would possibly collapse if the item in question were to be disturbed or removed then it is a structural member.

    A suspended ceiling is only designed to hold itself and maybe some accessories, not to reinforce other portions of the structure in any way.

    Been in remodels in old houses where plaster ceilings are in bad shape, and they maybe just drop a "hard ceiling" a little lower maybe some 2x4 or 2x6 members spanning across the room and cover with new drywall. That I would not call a structural ceiling - it's only function is to hold the ceiling finish up and not to provide any structural support or reinforcement.

  10. #20
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    Quote Originally Posted by kwired View Post

    If the structural ceiling is less than 6 feet above the top of the panel, then ducts or pipes can be above the panel, if they are also above the structural ceiling.
    And I just felt that it is splitting hairs and for purposes of this discussion his wording spelled it out just fine. One could just as well argue that the are not above the panel, the are above the ceiling. And I don't mean offence, I just agree with him.


    I know what I don't know, and I know where to go to find it!

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