IGR Wiring

[Alwayslearningelec]

So MC is not allowed when wiring a IGR? I did not know that. See below.


However, the Code does require you to ground the metal enclosure. This is automatic with a regular receptacle; you must provide an additional grounding means when using an IGR (unless you bond the enclosure to the IGR). The Code does not permit you to use interlock, or standard, type MC cable when wiring an IGR because the outer interlock sheath is not recognized as an effective fault current path to ground metal enclosures. However, you can use AC cable with an insulated equipment grounding conductor, because type AC cable armor is listed for use as an equipment grounding conductor.

 

[cpal]

Actually I think MC is acceptable for IG Ckts http://www.afcweb.com/pdfs/afc_cable_catalog/afc_mctuff_ig_0704.pdf

You need to order the right stuff.

 

[hunt4679]

They do make an IG mc cable has an extra groung wire w/ yellow stripe

 

[raider1]

They do make an IG mc cable has an extra groung wire w/ yellow stripe

Agreed, you can get a special MC cable designed with an isolated EGC.

The Code does not permit you to use interlock, or standard, type MC cable when wiring an IGR because the outer interlock sheath is not recognized as an effective fault current path to ground metal enclosures.

This is talking about standard MC.

Chris

 

[infinity]

I would use plain old HCFC or this new stuff HCF MCAP, I wouldn't want to have to terminate two EGC's at every junction.

http://www.southwire.com/products/HCFMCAPTypeMCAllPurposeHospitalCareFacility.htm

 

[raider1]

I would use plain old HCFC or this new stuff HCF MCAP, I wouldn't want to have to terminate two EGC's at every junction.

http://www.southwire.com/products/HCFMCAPTypeMCAllPurposeHospitalCareFacility.htm

That would make a much easier installation.

Chris

 

[infinity]

That would make a much easier installation.

Chris

Yup, if you do the math on a large commercial job you can save a significant amount of money on labor and also some on material costs since the cable will not need an extra copper conductor.

 

[Alwayslearningelec]

So is 12/2 or 12/3 MC w/ground good for IG receptacles?

 

[LarryFine]

MC isn't prohibited, using the jacket as an EGC is.

I have used 3-conductor MC for an IG circuit. I stripped the red fully at every point and used it as the regular EGC, and used the green as the IG conductor.

Right or wrong, it passed inspection with no problem.

 

[Alwayslearningelec]

Ron can you explain what you mean by splicing two EGC at every junction?? Thanks

 

[infinity]

Ron can you explain what you mean by splicing two EGC at every junction?? Thanks

There was a mention about using MC cable with 2 EGC's within the cable, one Green, the other Green/Yellow Stripe. When using that cable you'll need to terminate two EGC's at every device, splice, panel etc. By using HCFC or HCF MCAP (link in the photo above) you'll only need to terminate one EGC since the jacket of the cable will be the other EGC.

 

[Alwayslearningelec]

Thank you very much Rob