Hospital Grade MC

[roger]

I have not seen the HC cable in Roger's link with the full sized alum bond wire. I notice it does say to use the listed connector, because of that larger bond wire. I said I have seen MC with no green wire at all and an over sized alum bond. I thought it was MCAP (ap for all purpose). It was used in a retail clothing store. I will have to check if it is called MC or AC.

MC has an insulated EGC, the sheath of plain Jane MC is not recognized as an EGC in 250.118 whereas AC is recognized in 250.118. See articles 320 and 330 for the different rules.

Roger

 

[GerryB]

This link (if it works) if not goggle MCAP cable and a 2 minute Southwire video shows the cable I saw and the one in Roger's link.

 

[tom baker]

AFC had the market for HC for years with their green AC cable. Then Southwire came out with its smart MC and added an insulated green conductor and it could compete with AFC. Advantages for smart MC is support is 6 ft vs 4 1/2 for AC and no red heads required.
Seems like the mfgs include redheads with MC but they are not needed.

 

[hillbilly1]

All three of the above.

Roger

Just told my son that same thing, he's on a new medical building, and his foreman was telling them to wrap the wire six times, red devils, etc. (don't know where they come up with six wraps, LOL!)

 

[kwired]

I have not seen the HC cable in Roger's link with the full sized alum bond wire. I notice it does say to use the listed connector, because of that larger bond wire. I said I have seen MC with no green wire at all and an over sized alum bond. I thought it was MCAP (ap for all purpose). It was used in a retail clothing store. I will have to check if it is called MC or AC.

To be allowed to be used for art 517 applications wiring methods must qualify as a EGC themselves plus contain a copper EGC. That was the rule even before MCAP came out. Before then only healthcare approved cable was pretty much limited to AC cable that also included a green wire. If not using that cable you had to use metal raceway and pull a green wire in it, not really any other choices. When MCAP came out we finally had a MC cable that had a sheath that was considered to be an EGC - this allowed for using said cable with a green conductor to be able to also use this cable in healthcare applications. In non health care applications this MCAP is fine not having a green conductor - the sheath along with the bare bond wire that is in contact with the sheath is a qualifying EGC, the bare bond wire is there to short across the turns of the sheath and lessen overall impedance that sheath would have if there were not a bond wire inside. Same EGC principle applied to AC cables for many years.

 

[winnie]

Note with MCAP: the sheath in combination with the full size bond wire is considered the ground, and to take advantage of the labor savings you should cut the full size bond wire off per and just use the connectors.

However, if for any reason you want or need to use the wire ground itself, you _may_, as long as you use termination methods suitable for aluminium wire. You _may_ if you wish bring the wire into the junction box and splice it, land it on a terminal, etc. Probably a waste of time and material, but permitted.

-Jon

 

[kwired]

Note with MCAP: the sheath in combination with the full size bond wire is considered the ground, and to take advantage of the labor savings you should cut the full size bond wire off per and just use the connectors.

However, if for any reason you want or need to use the wire ground itself, you _may_, as long as you use termination methods suitable for aluminium wire. You _may_ if you wish bring the wire into the junction box and splice it, land it on a terminal, etc. Probably a waste of time and material, but permitted.

-Jon

But you can not use that bare aluminum bond wire as the second required EGC path that is required for art 517 applications, it is part of the wiring method path. You still need an additional insulated grounding conductor within the assembly - which is what listed "HC" cables are composed with whether they are AC or MC cable.

 

[winnie]

But you can not use that bare aluminum bond wire as the second required EGC path that is required for art 517 applications, it is part of the wiring method path. You still need an additional insulated grounding conductor within the assembly - which is what listed "HC" cables are composed with whether they are AC or MC cable.

Yes, I should have added that.

 

[electrofelon]

Yes, I should have added that.

Anyone know offhand the cost of MCAP vs regular MC?

 

[Beaches EE]

For 12/2G MCAP is typically 2 or 2.5x the cost of MC.

 

[kwired]

For 12/2G MCAP is typically 2 or 2.5x the cost of MC.

I presume you are talking about 12-2 with an insulated green (healthcare cable)?

I think electrofelon possibly was asking for comparison of regular MC vs two conductor (no green) MCAP. Theoretically it should be less cost for two copper and the aluminum bond wire vs three copper conductos, but they will say it takes more of something to make it that way and at very least will be at least same price?

 

[electrofelon]

I presume you are talking about 12-2 with an insulated green (healthcare cable)?

I think electrofelon possibly was asking for comparison of regular MC vs two conductor (no green) MCAP. Theoretically it should be less cost for two copper and the aluminum bond wire vs three copper conductos, but they will say it takes more of something to make it that way and at very least will be at least same price?

Yeah I was wondering about the non HC. Yeah it should be cheaper.

 

[goldstar]

Yup, but you can use them if you want to.

That is correct - not to mention - red heads are usually supplied with the coil of MC. I generally wrap a portion of that aluminum wire around the coil of the MC. The red-head helps to hold that wire in place. (I'm not looking to pirate this thread but some call this aluminum wire a bonding strip or a drain. I call it a shunt.) IMHO, although MC cable does not require the use of red heads, if the cable is supplied with a shunt wire as part of the cable assembly then red heads should be used. Not sure if that's addressed anywhere in the Code.

 

[infinity]

IMHO, although MC cable does not require the use of red heads, if the cable is supplied with a shunt wire as part of the cable assembly then red heads should be used. Not sure if that's addressed anywhere in the Code.

Not addressed directly but one of the manufacturers of the MC cable (AFC) say that redheads are provided in case they're required by a local code and that they're not required by the NEC.

"Although anti-short bushings are only required by the NEC ® for AC cable, some manufacturers supply them for both cable types in
the event that local codes override the NEC ® "

 

[hillbilly1]

They got some new HC today on the job my son’s at. He kept telling the foreman the bond wire does not have to be wrapped, but the foreman still wants it to be wrapped! He handed it to him and the foreman fought with the #10 bond and the connector, and then come up with “It’s the wrong connectors, we must wrap it six times around the armor” LOL!

 

[infinity]

They got some new HC today on the job my son’s at. He kept telling the foreman the bond wire does not have to be wrapped, but the foreman still wants it to be wrapped! He handed it to him and the foreman fought with the #10 bond and the connector, and then come up with “It’s the wrong connectors, we must wrap it six times around the armor” LOL!

I find it funny that someone would want to waste the time (and therefore the bosses money) to do something that is completely useless. Does anyone ever read the instructions that come with MC-ap?

 

[electrofelon]

When I was very green, and didn't even know what AC cable was, I went down to Maryland to help a friend of a friend with a basement remodel. Apparently AC is fairly common there. I was baffled by the super small and flimsy "egc". I remember carefully wrapping it around the ground screws in metal boxes. "What is with this ridiculous ground wire!" I remember saying multiple times

Really though, there are areas where AC is so uncommon, people at the supply houses don't even know what it is.

 

[LarryFine]

Really though, there are areas where AC is so uncommon, people at the supply houses don't even know what it is.

When they don't, mention BX.

 

[electrofelon]

When they don't, mention BX.

But then they say " they don't make that anymore."

 

[LarryFine]

But then they say " they don't make that anymore."

"Yes, they do, but they call it AC now."