cable clash

[thorn949]

why is there a difference in supporting mc and ac cable? one is 4 1/2 ft. and the other is 6ft. for mc cable?

 

[iwire]

I don't know but I like it, in this area steel trusses in buildings are usually 5' apart so being able to go six feet is a good thing.

 

[celtic]

Maybe it has to do with the EGC.
On AC you depend on the sheath - which can become "un-corrugated" and/or break the #16 bonding strip.
On MC you depend on an actual conductor or the #10 bonding strip [MC AP] which is a little but more substantial than a AC's bonding strip.

Just guessing here.

 

[TOOL_5150]

I wish the 6' applied to FMC though.. not 4.5' / 1' within a box.

~Matt

 

[ramsy]

I don't know but I like it, in this area steel trusses in buildings are usually 5' apart so being able to go six feet is a good thing

I'd like a picture of exposed MC, with 6ft supports. If not sagging or twisting around other cables, and spaced > 3ft, pray tell how so with those listed, loose fitting straps.

 

[iwire]

I'd like a picture of exposed MC, with 6ft supports. If not sagging or twisting around other cables, and spaced > 3ft, pray tell how so with those listed, loose fitting straps.

Of course it sags, why is that a problem?

 

[ramsy]

Of course it sags, why is that a problem?

Try a six foot 90 with that sag.

 

[petersonra]

I once saw some MC (at least I think thats what it was) running between two pipe racks about 20 feet up in the air hanging off what looked like a steel cable. The MC was wrapped around the cable, and maybe had some tie wraps, although it was high enough up I really could not tell.

I wonder if that was legal.

 

[iwire]

Try a six foot 90 with that sag.

The code is a minimum for SAFETY not how things look, it does not prohibit us from using more supports if we feel like it.

 

[ramsy]

The code is a minimum for SAFETY not how things look, it does not prohibit us from using more supports if we feel like it.

Perhaps we should appreciate inspectors viewing some of the code as a poor substitute for better design, better workmanship, or experience that just knows better?