Is it legit to un-BX a BX?

[darius]

Hi All,

I have a length of 3/3 BX wire that I was hoping to use as a feeder wire to a sub-panel I'm working on. The metal shield is pretty hard to get through some of the tight turns I need to go through so I am looking at this scenario:

The wire is about 25 feet long, I would like to remove about 4 feet of the metal shield at both ends and then run the individual wires from those points to the main panel and the sub on the other end. The 4 foot lengths of wire (now without the armor around them) would run through PVC conduits.

Does anybody know if the Ontario EC allows that?

Or perhaps someone has 25 feet of 6/3 and would like to swap it for my 3./3 (35 feet in all, never used)?

[sdhagar]

Nothing explicitly says you can't pull the armour back as you've suggested, but the question your ESA inspector will be looking to answer is whether you've provided suitable protection on the end sections where you've exposed the conductors. This would include the transition from armoured cable to conduit and the conduit itself. I'm not sure PVC conduit would be allowed (but I don't know all the details of your cable path & the installation environment).

[boskup]

cut the BX, put the anti-short bushing in it and terminate in a junction box; conduit with unsheathed wire emerges from other side of junction box.

[asindero]

cut the BX, put the anti-short bushing in it and terminate in a junction box; conduit with unsheathed wire emerges from other side of junction box.

The wire is gauge 3, sir, 3 conductors in metal armour. You cannot splice it just like that.

Legit or not, it's not practical to remove the armour and insert to another. Make the PVC bigger to accomodate the BX. PVC is not even needed. BX will stand alone as long as you don't pour cement on it.

[Mike in Orangeville]

What you're wanting to do isn't something that I have run into before, but I'd say that Boskup has the general idea. You'll need a junction box at each end of the armor to make the transition from armor to conduit. There is no rule that says the wire has to be cut and spliced in a junction box... you simply use it as a 'pulling box'. The armor stops, but the wires keep going happily and uncut. That having been said, personally I'd buy some appropriate romex and use that. You'll also find that you can buy the larger sizes (like #8) of single-conductor by the meter at an electrical supply place.

If in doubt, check with the inspector.

[Todd]

If you are having difficulties getting the BX in place how are you going to get the conduit which is ridgid in place Just remember that the Radii of Bends in Armoured Cables are as follows, the radius of the curve of the inner edge of the bends shall be at least 6 times the external diameter of the armoured cable. Rule 12-614 (1)

[J.P. Rap]

What you're wanting to do isn't something that I have run into before, but I'd say that Boskup has the general idea. You'll need a junction box at each end of the armor to make the transition from armor to conduit. There is no rule that says the wire has to be cut and spliced in a junction box... you simply use it as a 'pulling box'. The armor stops, but the wires keep going happily and uncut. That having been said, personally I'd buy some appropriate romex and use that. You'll also find that you can buy the larger sizes (like #8) of single-conductor by the meter at an electrical supply place.

If in doubt, check with the inspector.

Could he not terminate the BX in a 90 deg. pull through then continue with conduit from there?
Or...Can you use a 90 deg. pull through (or a conduit body)to make the corner and use BX in and out?
I don't know if that's allowed or not.


For those of you that don't know...
This is a pull though (one type)...

051411144050.jpg
and this is a conduit body...

[Mike in Orangeville]

The small elbows are generally for direct connection of EMT, so that wouldn't work (no way to attach the armored cable) but a full-size LB as shown in the bottom part of your message has threads for rigid conduit, and that could have a fitting screwed into it to accept the armored cable, which means it would work like an outlet box, and would be an option. That having been said, he's talking about PVC conduit, which I don't work with, but I think the LBs are made with smooth sockets for gluing in the conduit, so if you want to thread something into it you have to buy a threaded 'liner' for the socket, then glue it in and screw in your fitting. Whether he can get a fitting big enough for the #3 conductors but small enough to screw into the liner in an appropriately-sized LB is a whole 'nother question, and I don't have the answer.

[Todd]

If he is going to use PVC and then use say a LR or a LL or most commonly used a LB for getting the BX into the PVCt you need to use a PVC Female Adapter which has internal threads in the one end and the other is glued onto the PVC. A BX connector probably a L19 will probably be the proper size for 3/3 BX don't forget the anti short. You will need to use 1 1/4" PVC, now the L19 is 1" so you will need a 1 1/4" - 1" threaded reducer for the L19 to fit into the female adapter. Then just pull the wire thru the conduit and into the panel and terminate properly.

[dave_k]

First off I'm a carpenter NOT an electrician. I firmly believe the risks involved in doing an improper job wiring far outweigh any cost savings you may get from cutting corners.

I am trying to imagine what kind of junction box you'd need for #3 cable. You certainly don't want to terminate it at an outlet ;-) You may be able to terminate in a disconnect and pull it off that way? I'm not sure if there are any rules about where you can put a disconnect switch.

[asindero]

I am trying to imagine what kind of junction box you'd need for #3 cable. You certainly don't want to terminate it at an outlet ;-) You may be able to terminate in a disconnect and pull it off that way? I'm not sure if there are any rules about where you can put a disconnect switch.

The box should be 12"x12"x6". Solderless connectors are more expensive than the BX itself. If you use terminal lug and bolts which are cheaper, you will need a crimper which is very expensive. Very impractical indeed.

[Albert]

Note sure if this is clear- the problem is that PVC does not ground the metal shield so a metal connector with a metal box is required or a ground bushing in a PVC box. You must ground all metal legally.

Call a local electrical contractor and have them drop in at the end of thier day. If they finish work early that day you may get a break and peace of mind.

Albert

[darius]

I see the thread has been dug out. Thank you for all the responses.
I managed to do without un-BX-ing the BX. A different wire layout and angles of attack made the smooth transitions possible.

I completed all work a few months ago and everything is working just fine. Of course I had applied for a permit to ESA and the work was inspected by an electrical inspector.