MC Support

Larry007

When did they make the code change to MC cable? I could have swore it was 4'6", but it is now 6'. I am not in the field as much as I use to be, so when asked I said 4'6". I stand corrected....

mdshunk

I can only remember 6' (NEC 330.30) for type MC cable.

Type AC cable is, and was as far back as I know, to be supported at 4-1/2'. Perhaps you got the two mixed up, since they both have the same general appearance? Or perhaps you were working with type AC before? Perhaps the "old timer" that taught you used the 4-1/2' AC rule for MC also?

In any event, it's of little consequence, since if you did it according to your memory, you'd have done better than code.

onewaywatt

i would have bet that the supports for ac is three feet apart and twelve inches from boxes.

mdshunk

Twelve inches from the box is for secured.

Here's the code sections:

320.30 Securing and Supporting.

ATS

Supporting mc and bx in commercial buildings can be soo dang time consuming and seemingly unnecessary, probably why so many times it is just strung about. It's nice though when it's at least on the top side of the framing members and not just lying on top of the ceiling tiles.

mdshunk

When I don't have bar joists above the ceiling to rope the MC cable through, I use these puppies on the ceiling support wires: http://www.erico.com/products/CADDYc...uitHangers.asp

ATS

Yep, the good ole batwings, I don't think we're allowed to do that anymore. Use the ceiling support wires that is.

mdshunk

It kinda depends. If it's a fire rated drop ceiling, you need to run your own drop wires. If it's a ceiling drop wire that exists, but not necessary to hold the ceiling up, then you can use it. Otherwise, you're running your own drop wire.