junction box location

[LARRY DILLARD]

commercial project, wood joist for roof support, there will be suspended ceiling 2' below wood joist. is it permissible to mount jb on bottom of joist. local authority wil not allow. says it has to be 18'' above bottom of joist in case it gets insulated so that it will be accessible and be seen

 

[ActionDave]

I'm a little confused what you are saying is above and below, but what you describe is not an NEC code violation. Local amendments are always something to check for and ask about.

 

[al hildenbrand]

wood joist for roof support

Do you mean the roof deck is supported by wood rafters? -Or- Do you mean a roof system is supported on walls framed with wood joists?

With respect to future insulation, is the insulation called out in the plans (or the general contractor's intention)? -Or- is the insulation only in the inspector's mind?

 

[kenman215]

commercial project, wood joist for roof support, there will be suspended ceiling 2' below wood joist. is it permissible to mount jb on bottom of joist. local authority wil not allow. says it has to be 18'' above bottom of joist in case it gets insulated so that it will be accessible and be seen

Also a little confused. Sounds like you're saying that there's a drop ceiling hanging 2' below a wood joist framed ceiling, presumably to provide space for mechanicals? And the inspector wants the box 18" above the bottom of the joist? Did you mean below the bottom of the hoist, above the ceiling?

 

[JFletcher]

Welcome to the forum. As has been mentioned many times here, "accessible" and "readily accessible/easily seen/quick access" are not the same thing.

Can you not mount the j-box on the wall between the drop ceiling and the trusses/joists?

If it is spray foam insulation that cannot be moved, he might have a point. Or were you intending to mount the box with the cover face-skyward so that one might have to dig thru insulation to find it (as opposed to downward, so that removing a ceiling tile would be the access)?

 

[LARRY DILLARD]

junction box location

sorry for confusion. the joist support roof. below the joist there will be suspended ceiling. i wanted to bring my circuit from panel to first office and set a jb on bottom of joist opening down. use jb to jump down to switch and return for switch legs. use same jb to continue circuit to next office etc. i was told this was not allowed, that jb has to be 18'' above bottom of joist in case in the future it would be insulated. at the present time there is not to be any insulation because roof deck gets insulation on top of structure. all wiring to be using mc.

 

[ptonsparky]

Draw a picture.

What If rules are tough ones.

I need one hat please because I only have one head.
What if you grow another? You have to buy two.

Ask for a code reference. Even if it is local it needs to be written somewhere.

 

[al hildenbrand]

the joist support roof. below the joist there will be suspended ceiling. i wanted to bring my circuit from panel to first office and set a jb on bottom of joist opening down. . . at the present time there is not to be any insulation because roof deck gets insulation on top of structure. all wiring to be using mc.

The NEC is silent about this. That is, nothing in the Code prevents the junction box from being installed on the bottom of the wood framing that supports the roof deck (in what I can understand of your situation).

 

[J.P.]

So he wont let you put j boxes on the BOTTOM joist that are getting decking and insulation on TOP of them? Ooooookaaaay.:dunce:
Pretty much every building has j boxes facing down on the ceiling with or without insulation.

Maybe run you lighting power from switch to switch and leave switchlegs rolled up for the first light then daisy chain them.

Insulation on drop ceilings usually goes on top of the tiles anyway.

You need to get a code reference from him if he's going to be an idiot. Most inspectors in my experience are decent people.

 

[J.P.]

I just had a thought. Is it a drywall drop ceiling by any chance. Finished off solid and non- accessible? The light openings could be access points if they are 1x4 or 2x2 light or something like that.

I did some schools with flush mounted troughers in a drywall drop ceiling and put all my j boxes in the hallways where there were tiled ceilings.

 

[kwired]

I just had a thought. Is it a drywall drop ceiling by any chance. Finished off solid and non- accessible? The light openings could be access points if they are 1x4 or 2x2 light or something like that.

I did some schools with flush mounted troughers in a drywall drop ceiling and put all my j boxes in the hallways where there were tiled ceilings.

What I am understanding from OP description is there is open truss construction with no drywall or other covering to form a continuous surface on the underside of the trusses. There is insulation on top end or under the roofing though whether it is sheet insulation under the roof or spray on.

What I would be present to the inspector is how are they going to add insulation later to the area in question if there is nothing there to support it? To place additional insulation to the traditional space just above lower level of the trusses, you need something covering the lower face of those trusses or that insulation will fall down to the suspended ceiling, or at least some strapping to help hold "batt" type insulation in place, or it will often end up falling down the road. If that is how it is done OP's boxes are still accessible through the suspended ceiling panels.

 

[J.P.]

I meant a drywall drop ceiling. Heavy T grid suspended form grid wire with drywall screwed to it. Looks like a normal drywall ceiling when finished.

A tile ceiling would be accessible anywhere.

The drywall drop ceilings are accessible if you can fit through the trofferer hole....


Or do you mean you just look up and see the truss's from the floor after the building is finished?

I don't see the problem either way. I would set bracket 4x4s out 1/2" just incase case they do cover it at some later date. Maybe it's in some odd area?

 

[kwired]

Junction boxes in loose fill insulation are still accessible. May not be so easy to find, you can use some kind of flagging method to help identify where they are. Some places fill to more then 18 inches deep as well.