MC Inside EMT or RGC

[gadfly56]

So, my tech ran across this issue at a work site. Multiple MC's for 120VAC to fire alarm equipment that come into the first panel via conduit. The MC's aren't terminated on entry into the enclosure (how could they be?) and then run down to the transformer for the first panel and then pass through that panel into the remaining enclosures. Is this permitted? 330.10(A)(7) seems to suggest it is, but he's concerned about the end of the cable not being secured by a connector.

 

[jap]

I would say MC Cable not properly terminated would not be permitted,,, how could it be?

JAP>

 

[petersonra]

330 10a.7 says in any raceway.

Is there some way to secure it to the conduit when it comes out of the end of the conduit?

 

[jap]

If it's not terminated do the ends of the MC Cable even have a fitting on them at all?, or, is it just cut with the conductors poking out the ends of the armor?

JAP>

 

[gadfly56]

Here's a picture of the current condition. It's likely that most of the FPLP will be removed by the end of our work, so let's ignore that for now.

 

[gadfly56]

I would say MC Cable not properly terminated would not be permitted,,, how could it be?

JAP>

Would 300.15(C) change your mind?

 

[ActionDave]

300.10 says cables have to end in a fitting.

 

[jap]

Would 300.15(C) change your mind?

Nope,,, this is just as I pictured it.

JAP>

 

[petersonra]

300.10 says cables have to end in a fitting.

300.10 Electrical Continuity of Metal Raceways and Enclosures.
Metal raceways, cable armor, and other metal enclosures
for conductors shall be metallically joined together into a
continuous electrical conductor and shall be connected to all
boxes, fittings, and cabinets so as to provide effective electrical
continuity. Unless specifically permitted elsewhere in this Code,
raceways and cable assemblies shall be mechanically secured to
boxes, fittings, cabinets, and other enclosures.

Since 330.10(A)(7) specifically allows MC in a raceway, it would seem that the "Unless specifically permitted elsewhere in this Code" language is satisfied, otherwise 330.10(A)(&) would be meaningless.

 

[gadfly56]

Nope,,, this is just as I pictured it.

JAP>

How about 300.16(B)?

(B) Bushing. A bushing shall be permitted in lieu of a box or
terminal where the conductors emerge from a raceway and
enter or terminate at equipment, such as open switchboards,
unenclosed control equipment, or similar equipment. The
bushing shall be of the insulating type for other than lead-
sheathed conductors.

 

[jap]

How about 300.16(B)?

(B) Bushing. A bushing shall be permitted in lieu of a box or
terminal where the conductors emerge from a raceway and
enter or terminate at equipment, such as open switchboards,
unenclosed control equipment, or similar equipment. The
bushing shall be of the insulating type for other than lead-
sheathed conductors.

I would consider the "Raceway Bushing" that round blue thing at the top of the picture, not conductors sticking out of the end of a manufactured piece of MC cable.

What is pictured is not an open unenclosed enclosure such as an open bottomed switchboard.

What's pictured is an "enclosed" piece of control equipment.

JAP>

 

[hbiss]

(B) Bushing. A bushing shall be permitted in lieu of a box or
terminal where the conductors emerge from a raceway

Operative word here is conductors.

-Hal

 

[jap]

Yes, and, MC Cable is just that,, a "cable", not a "raceway", and, in the picture a cable that's being installed in a "raceway".

Oh well.

Raceway. An enclosed channel of metal or nonmetallic materials
designed expressly for holding wires, cables, or busbars,
with additional functions as permitted in this Code.
Raceways include, but are not limited to, rigid metal conduit,
rigid nonmetallic conduit, intermediate metal conduit, liquidtight
flexible conduit, flexible metallic tubing, flexible
metal conduit, electrical nonmetallic tubing, electrical metallic
tubing, underfloor raceways, cellular concrete floor raceways,
cellular metal floor raceways, surface raceways, wireways,
and busways.

JAP>

 

[GoldDigger]

How about 300.16(B)?

(B) Bushing. A bushing shall be permitted in lieu of a box or
terminal where the conductors emerge from a raceway and
enter or terminate at equipment, such as open switchboards,
unenclosed control equipment, or similar equipment. The
bushing shall be of the insulating type for other than lead-
sheathed conductors.

The OP's installation does not appear to be open.
An alternative would be to treat the raceway as a sheath and terminate it short of the box, then use MC filttings to enter.
Obviously not suitable if it also contains FPLP conductors.
As a practical matter, using an insulating board and hold down clips inside the box would make a cleaner but still probably not legal configuration.
You could also use an external junction box to terminate the MCs entering via fasteners and transition to individual wires to run into the control enclosure.

 

[gadfly56]

Operative word here is conductors.

-Hal

Wouldn't a "red hat" at each MC protect the conductors?

 

[jap]

Yes, anti short bushings do protect the conductors from the MC Cable's outer jacket , but, the post is about terminating the MC cable to an enclosure.

Jap>

 

[hbiss]

Wouldn't a "red hat" at each MC protect the conductors?

MC does not require red hats. But the problem here is that the sheath of the MC has to be electrically bonded to the cabinet or box which is what a connector in a KO would do.

-Hal

 

[gadfly56]

MC does not require red hats. But the problem here is that the sheath of the MC has to be electrically bonded to the cabinet or box which is what a connector in a KO would do.

-Hal

So, I think I'm hearing that the MC needs to be terminated at a trough or box with proper bonding, then the conductors could be dropped down the conduit into the fire alarm enclosure.

 

[acrwc10]

MC does not require red hats. But the problem here is that the sheath of the MC has to be electrically bonded to the cabinet or box which is what a connector in a KO would do.

-Hal

I agree with this statement and would add, “how did the MC enter the conduit?” is the other end bonded?

 

[jap]

Well,,,, most times the anti short bushings aren't required because the installation of the fittings protects the conductors..

Without the fittings, nothing protects the conductors hanging out the end of the metal sheath.

But then again, why would anyone ever install MC cable simply cut off with the conductors hanging out ,without a connector to protect them as in the picture?

Not me.

JAP>