Wiring within a mullion?

[dunbarx]

First post here.

We manufacture custom lighting products, and are requested to create a thin linear fixture mounted to an indoor mullion. The mullion is a hollow aluminum extrusion. Before we agree to create this fixture, is it permitted to dress electric wiring inside the mullion? Our fixture "ends" at the K.O., but we do not want to infer that the power feed is to be fed through the mullion if in fact that is prohibited

 

[petersonra]

First post here.

We manufacture custom lighting products, and are requested to create a thin linear fixture mounted to an indoor mullion. The mullion is a hollow aluminum extrusion. Before we agree to create this fixture, is it permitted to dress electric wiring inside the mullion? Our fixture "ends" at the K.O., but we do not want to infer that the power feed is to be fed through the mullion if in fact that is prohibited

Luminaires are required to be listed. Your best bet is to ask UL. My guess is as long as the wiring is well protected UL will accept it. However, the devil is always in the details. My opinion is that your fixture ends with whatever you actually ship, not what you arbitrarily decide. I don't think you get to decide where your fixture ends. that would seem to be up to UL. if UL agrees with you that the mullion is not part of the fixture than it is not your problem and you should just leave it alone.

Your other option might be to include instructions that the mullion is not to be used as a raceway. Incidentally, that would not preclude someone from putting a cable or raceway inside the mullion, it only instructs that the mullion itself cannot be used as a raceway.

 

[Kansas Mountain]

Low voltage wiring within mullions is common. Linked below is an example of another fixture that is standard designed to mount to mullions. Assuming you're working with a remote driver, you'll only need low voltage wiring within the mullion itself. Also common for controlled access systems, motorized doors, etc.

Spec Sheet
Install Instructions

 

[petersonra]

if it is class 2 wiring they can pretty much do as they please.

 

[dunbarx]

Thank you all.

I should have mentioned that our fixture is UL listed, and that a 120 VAC class 1 circuit powers it.

It is just the odd installation surface that made me ask, that is, not a simple ceiling but rather a field of mullions that support a large but typical glass panel structure. We were not quite sure how to prepare the power feed instructions, beyond simply showing the entry K.O. and leaving it there.

Frankly, we still are not sure, since the client may expect more from us, instead of leaving it entirely to the EC.

Craig

 

[Kansas Mountain]

If you are bringing line voltage wiring directly to the fixture, the contractor just needs to use some sort of raceway within within the mullion like MC cable, AC cable, metal flex, etc. The mullion itself is not a raceway unless that particular manufacturer got it listed as such, so the contractor should not just run individual conductors.

 

[Kansas Mountain]

IMO, design the light, add a few CYA notes if you want, and get paid.

 

[dunbarx]

Thanks again.

Nothing I like better than leaving the experts to deal with problems. We will do just that, saying that if the mullion is not a listed raceway, then it is the responsibility of the EC to prepare the mullion properly.

Gettin paid is another issue entirely.

Crg

 

[LarryFine]

I've seen narrow switch boxes and plates that fit in some mullions.

I have fished MC with an angle connector down a mullion and pulled the threaded end through a 7/8" hole and into a box or into other fittings.

 

[dunbarx]

We are told that only the vertical portions of the mullion grid are continuous, the horizontals being blocked at their sides. This might either complicate or simplify the circuit wiring.

You make a point, though, that we may be well served to propose a utility compartment for the use case.

Thank you.

Craig

 

[GoldDigger]

I think the chances of encountering this in an existing building would be one in a mullion.