MC Cable

[augie47]

An installation consists of PVC Enclosures with standard corrugated sheath MC run between the enclosures. I am of the opinion that steps must be taken to bond the MC based on 250.86. Any input ?

 

[don_resqcapt19]

314.3 Nonmetallic Boxes
Nonmetallic boxes shall be permitted only with open wiring on insulators, concealed knob-and-tube wiring, cabled wiring methods with entirely nonmetallic sheaths, flexible cords, and nonmetallic raceways.

Exception No. 1: Where internal bonding means are provided between all entries, nonmetallic boxes shall be permitted to be used with metal raceways or metal-armored cables.

 

[iwire]

An installation consists of PVC Enclosures with standard corrugated sheath MC run between the enclosures. I am of the opinion that steps must be taken to bond the MC based on 250.86. Any input ?

Yes the sheath still needs a connection to ground even if it is not being used as an EGC.

Don pointed out a good code reference.

 

[infinity]

I agree with Don and Bob. Not sure what the solution is unless the box meets Don's code section.

 

[gadfly56]

I agree with Don and Bob. Not sure what the solution is unless the box meets Don's code section.

Why not use bonding jumpers?

 

[Little Bill]

How would you bond it?
Small bonding nut on an appropriate MC connector?

 

[gadfly56]

How would you bond it?
Small bonding nut on an appropriate MC connector?

That was my assumption, although a quick look at the RACO and PECO web sites doesn't seem produce suitable products.

 

[FionaZuppa]

How would you bond it?
Small bonding nut on an appropriate MC connector?

a bonding lock nut or washer inside the pvc box, tied to gnd? assumed the box is a jb and not just a pull box. if a pull box then you'll need to splice the gnd, or, move to metal.

 

[jumper]

Yes the sheath still needs a connection to ground even if it is not being used as an EGC.

Don pointed out a good code reference.

I agree with Don and Bob. Not sure what the solution is unless the box meets Don's code section.

Ditto.

 

[iwire]

Wonder why they used PVC boxes with MC anyway?

 

[peter d]

Wonder why they used PVC boxes with MC anyway?

Probably because they were clueless. :thumbsup:

 

[FionaZuppa]

sorry, the 2nd proper option, if a pull box then just use bonding nut/washer on each side and connect those two together. the end points will obviously need to be tied to gnd, etc. metal boxes just seem easier.

 

[iwire]

I have a bunch of 1/2" bonding bushings that would work for this.

I had to buy them when I was retrofitting new vapor proof LED fixtures in place of old T-12HOs. The new fixtures where entirely plastic, the old fixtures where metal with 1/2" EMT run between them.

There was a wire EGC in the EMT but I had to use bonding bushings to tie it into the EMT entering the fixtures.

 

[mbrooke]

I like the ones you can use after all the wire is pulled :lol::rant:

 

[kwired]

a bonding lock nut or washer inside the pvc box, tied to gnd? assumed the box is a jb and not just a pull box. if a pull box then you'll need to splice the gnd, or, move to metal.

If you run MC into the box chances are there will be splices to connect to the MC cable.

Why run PVC box and MC cable? Strange things do come up fro time to time, often when dealing with something existing.

 

[FionaZuppa]

If you run MC into the box chances are there will be splices to connect to the MC cable.

very true, very true. my mind was not in "MC" mode

 

[infinity]

Augie mentioned PVC enclosures, Don's reference is for boxes. Are the requirements the same for boxes and enclosures?

 

[don_resqcapt19]

Augie mentioned PVC enclosures, Don's reference is for boxes. Are the requirements the same for boxes and enclosures?

What is the difference? Are those terms defined in the NEC?