Cotton/rubber cable in MC clamps

[rabtrfld]

This type of jbox (see pic) has KOs & clamps for MC, but I constantly see old ones with similar clamps used with that ancient cotton-braided rubber-insulated stuff (what do you call that junk anyway?)

Was this ever legal? There is never any bushing on the KO hole. Often the cotton cable gets replaced with NM, still no bushing. The hole isn't even big enough for a snap-in bushing.

BTW, why does the copper seem so much stiffer in that old wire? Is it age, or a different alloy?

 

[brantmacga]

i always pop those clamps out when rewiring with existing box.

 

[benaround]

rabtrfld,

I think you are refering to the old 'BX' cable, it's similar to mc cable, but the

only EGC was the metal sheath, actually some of it had an Alum. ribbon also

run inside with the conductors. At the time it served the purpose, but over

time,IMO, it got quite dangerous. The reason was the inability to clear a fault

due to loose locknuts, fittings, etc. I have more that once seen sections of

'bx' glowing red just like the wires in a toaster. This is when I learned what

time is of the essence meant.

 

[M. D.]

If those are M.C. clamps pictured,..and they look it to me ,.. there is no anti short bushing required,...if you were o use one you would put in the cut end of the cable before you insert it into the box clamp.

As for the cloth covered cable you would have to know what year and if it was prohibited ,... whether it was or was not ,. it has done the job for quite some time.

 

[rabtrfld]

I meant that one should use MC, not NM, when rewiring old ones

 

[SEO]

I meant that one should use MC, not NM, when rewiring old ones

What's wrong with NM cable?

 

[rabtrfld]

The knockout hole is raw... no bushing

 

[MF Dagger]

The ones that are only unclamped from the outside of the box are really really classic to work with.

 

[mdshunk]

The ones that are only unclamped from the outside of the box are really really classic to work with.

Ah yeah. Normally 1" deep pancakes, with a screw in through the side of the box. They're a treat. You normally end up with 20 pounds of plaster on the floor trying to rework one of those boxes.