Supporting multiple MC cables within 12" around the periphery of a suspended J-box.

[Jon456]

There's are existing J-boxes above a drop ceiling; the J-boxes are suspended from roof trusses. I am removing old fluorescent troffers and re-lamping the space with LED troffers. The lighting layout and number of fixtures have changed, so I've removed all the old wiring and am installing new MC cable for the new LED troffers. Incidentally, none of the old flex was independently supported beyond 6' (in fact, it was not supported at all).

Now that I am adding more cables (some of which are longer than 6') to the J-boxes, and originating from 3 or 4 sides of each J-box, I'm trying to figure out how to add independent support wires to support the cables within 12" of the box without creating a "cage" of hanger wires surrounding the J-box from the roof to the grid. Any recommendations for a clean install?

(Btw, I've replaced the old J-box with a larger one to accommodate box fill requirements.)

 

[LarryFine]

Bridle rings?

 

[Jon456]

Bridle rings?

The issue is not how to attach the MC to the independent support wires. I intend to use Caddy KX clips to connect the cable to the wires. The issue is surrounding the J-box with three or possibly even four support wires, each no more than 12" from a side. Not only would it be a "messy" install to connect all those wires to both the roof trusses and the suspended ceiling grid, but it seems to me that it would interfere with working access to the box.

 

[petersonra]

I don't see how a wire can be used to "secure" the MC cable. Support yes, but not secure, and the rule regarding 12 inches is about securing.

Take a look at 330.30(D) and see if you can make your application not require supporting or securing.

Otherwise, something is securing and supporting the junction box. Maybe hang some strut off of it to tie wrap the MC to.

 

[Jon456]

I don't see how a wire can be used to "secure" the MC cable. Support yes, but not secure, and the rule regarding 12 inches is about securing.

Take a look at 330.30(D) and see if you can make your application not require supporting or securing.

Otherwise, something is securing and supporting the junction box. Maybe hang some strut off of it to tie wrap the MC to.

This is why wires hanging in midair are not permitted under 300.11(A): they would provide only support but are not "secure." According to 300.11(A), wires "shall be secured at both ends" which is what makes them "secure."

As for the J-boxes in question, they are suspended in midair from EMT conduit that drops down from the roof trusses per 314.23(E). But that means they can't be used to hang strut.

 

[electrofelon]

Bridle rings?

Sounds like a big commitment to me

 

[Jon456]

To help visualize the issue, I drafted up this 3D CAD model. I'm trying to avoid the J-box being encircled by support wires (colored orange in the model) because they will hinder access to the box and it will be a challenge to attach them at the top to the roof trusses and at the bottom to the suspended ceiling grid. Surely I'm not the first person to encounter a scenario like this.

 

[LarryFine]

Can conduit support plates work?

 

[Jon456]

Can conduit support plates work?

View attachment 2558033

Thank you, Larry, that's brilliant! I've never seen those before. I just ordered a couple of the smaller model support plates by the same manufacturer (Orbit BCHS-10).