Hospital grade mc for lights

[sybenn]

Had an inspector say I was ok to run normal 12/2 for lighting whips in treatment rooms and another inspector failed me on it. Said I had to run hospital grade for the whips. The receps are all hospital grade. The boxes for the lights are all above ceiling does the code say I have to run hospital grade for light whips?

 

[roger]

Had an inspector say I was ok to run normal 12/2 for lighting whips in treatment rooms and another inspector failed me on it. Said I had to run hospital grade for the whips. The receps are all hospital grade. The boxes for the lights are all above ceiling does the code say I have to run hospital grade for light whips?

517.13(B) Exception No 2 says you do not need an insulated EGC to fixtures above 7.5' but 517.13(A) requires the metallic sheath of the cable to be recognized as an EGC per 250.118, regular MC does not meet this requirement but AC would.

FMC would also work but you would have to be sure it complied with the specifics covering it in 250.118.

Roger

 

[sybenn]

Because I used regular mc it had an insulated ground used it. The inspector said I have to use the hospital grade with the extra aluminum ground in it. But the lights are above 7'


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[roger]

Because I used regular mc it had an insulated ground used it.

That won't work, it does not comply with 517.13(A)

The inspector said I have to use the hospital grade with the extra aluminum ground in it. But the lights are above 7'

If the fixtures are not at least 7' 6" the inspector is correct, the wiring method will have to comply with 517.13(A) and (B)

Roger

 

[sybenn]

That was my fear thanks


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[roger]

That was my fear thanks


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You're welcome and I hate to be the bearer of bad news.

Roger

 

[buzzbar]

Perhaps I'm wrong, but the specs on the standard MC cable that we use says the following:


Grounding One grounding means - Combinedarmor and full-sized aluminumground/bond conductor NEC®250.118(10)(b)

Would this not comply with 517.13 (A)? For what it's worth, we do a lot of health care wiring, and we've always used standard MC for the light fixtures in the grid above. The switch legs are usually ran in EMT or HCF MC cable.

 

[roger]

Perhaps I'm wrong, but the specs on the standard MC cable that we use says the following:


Grounding One grounding means - Combinedarmor and full-sized aluminumground/bond conductor NEC®250.118(10)(b)

Would this not comply with 517.13 (A)? For what it's worth, we do a lot of health care wiring, and we've always used standard MC for the light fixtures in the grid above. The switch legs are usually ran in EMT or HCF MC cable.

That particular cable would comply but, those specs are not for standard MC, they are for a MCAP type of cable, plain Jane MC does not have an aluminum shunting wire along its length.

Roger

 

[buzzbar]

Hmm, it's the 'plain Jane' MC cable that we use every day. Here's a link to the full spec sheet:

https://www.platt.com/CutSheets/AFC/Stranded MC.pdf

I thought all MC cable followed this spec. Glad to know it complies though.

 

[augie47]

That particular cable would comply but, those specs are not for standard MC, they are for a MCAP type of cable, plain Jane MC does not have an aluminum shunting wire along its length.

Roger

Roger:
I agree that the fine line difference with "standard" MC and Healtcare MC such as MCAP is the MCAP, unlike MC, has an outer jacket that is in itself an approved grounding means.

That said, it is my understanding (or misunderstanding) that both have a bond wire but MCAP has a full size bond giving it the approved grounding means.

(both have a full length bond but different size I believe)

 

[augie47]

Hmm, it's the 'plain Jane' MC cable that we use every day. Here's a link to the full spec sheet:

https://www.platt.com/CutSheets/AFC/Stranded MC.pdf

I thought all MC cable followed this spec. Glad to know it complies though.

From the cut-sheet, I fail to see where that product is listed for Art 517 applications.

 

[buzzbar]

From the cut-sheet, I fail to see where that product is listed for Art 517 applications.

It doesn't comply with the redundant ground aspect, but I'm referring to this section:

517.13 Grounding of Receptacles and Fixed Electrical Equipment in Patient Care Areas

Wiring in patient care areas shall comply with 517.13(A) and (B).

(A) Wiring Methods. All branch circuits serving patient care areas shall be provided with an effective ground-fault current path by installation in a metal raceway system, or a cable having a metallic armor or sheath assembly. The metal raceway system, or metallic cable armor, or sheath assembly shall itself qualify as an equipment grounding conductor in accordance with 250.118.


On the spec sheet, it says:

Grounding One grounding means - Combinedarmor and full-sized aluminumground/bond conductor NEC®250.118(10)(b)

Looks to me like the MC cable complies with 517.13 (A). Do you agree?

 

[roger]

The problem with your link is it's not for standard MC, it's for a Hybrid, standard MC does not have a shunting wire.

From AFC's website;

Q: What is an AC Cable?
A: Armored Cable is an alternative to traditional pipe and wire electrical installations. Armored cable wraps the insulated copper conductors individually with paper within a metal sheath.
Armored cable is manufactured to UL^® standard UL^® 4 and is limited to four phases and neutral conductors with size limitations of 14 AWG to 1 AWG and contain a 16 AWG bare aluminum bond wire to be used in conjunction with the armor as a ground path.
Q: What is an MC Cable?
A: Traditional MC Cables have a THHN/THWN insulated copper conductor with polypropylene wrap and are designed to meet UL^® 1569 standards. Metal Clad Cable or MC Cable will have one or more grounding conductors.
Q: What is the difference between MC Cable and AC Cable?
A: Major differences between Type AC and MC are the trade size. AC Cables range from 14 AWG through 1AWG, whereas MC Cables can range from 18 AWG through large feeder size cables.
AC Cables have insulated conductors that are wrapped with a moisture resistant, fire retardant Kraft paper whereas MC Cables come with an overall polypropylene wrap.

Another difference between the two cable types is the ground path. AC uses a bare aluminum bond wire plus the armor as the ground path, Traditional Type MC Cables utilize a green insulated grounding conductor and the armor is not an approved grounding means.

Roger

 

[roger]

Roger:
I agree that the fine line difference with "standard" MC and Healtcare MC such as MCAP is the MCAP, unlike MC, has an outer jacket that is in itself an approved grounding means.

That said, it is my understanding (or misunderstanding) that both have a bond wire but MCAP has a full size bond giving it the approved grounding means.

(both have a full length bond but different size I believe)

Gus, you are correct that MCAP has a bond wire (and an insulated EGC) which it is larger than it's AC or HCFC cousin which uses a #14 equivalent
The "MC Quick" (shown in the link) is different in that it does not have an insulated EGC and the sheath combined with the bare aluminum conductor is the only grounding, kinda sounds exactly like AC.

Roger

 

[buzzbar]

The problem with your link is it's not for standard MC, it's for a Hybrid, standard MC does not have a shunting wire.

From AFC's website;



Roger[/SIZE][/SIZE]

Thanks for pointing that out. This is the type of MC cable that we use for all of our work, I just assumed that it was the "plain Jane" stuff. I guess that explains why I've never been corrected by the AHJ when used in ceilings in patient care areas.

I would suggest that the original poster checks, and verifies what type of MC cable he used.

 

[kevin]

I agree entirely with Roger's analysis of this issue - exactly identical to that which an electrical contractor friend of mine faced two weeks ago. The question was whether he could install traditional MC cable (with a green insulated wire-type EGC, but without the sheath being approved as an EGC) as a wiring method to luminaires located more than 71/2 feet above the floor. The state electrical supervisor surprisingly ruled YES: he said that that wiring method was superior to one in which only the cable sheath was approved as an EGC. I agree with him, but that is not what the Code seems to say. Perhaps for the 2020 Code cycle a proposed change to 517.13(B)(1) Ex No.2 to (3) would be in order?

Incidentally, the term "hospital grade MC" should be abandoned; it has been used inaccurately for too many years. It is a fallacious description for Type AC (the sheath is an approved EGC) that also includes a green insulated wire-type (redundant) EGC. Consequently, an insulated (anti- short) bushing is required required at all Type AC terminations (320.40). The insulated bushing is not required for Type MC (Art. 330).

 

[augie47]

I agree entirely with Roger's analysis of this issue - exactly identical to that which an electrical contractor friend of mine faced two weeks ago. The question was whether he could install traditional MC cable (with a green insulated wire-type EGC, but without the sheath being approved as an EGC) as a wiring method to luminaires located more than 71/2 feet above the floor. The state electrical supervisor surprisingly ruled YES: he said that that wiring method was superior to one in which only the cable sheath was approved as an EGC. I agree with him, but that is not what the Code seems to say. Perhaps for the 2020 Code cycle a proposed change to 517.13(B)(1) Ex No.2 to (3) would be in order?

Incidentally, the term "hospital grade MC" should be abandoned; it has been used inaccurately for too many years. It is a fallacious description for Type AC (the sheath is an approved EGC) that also includes a green insulated wire-type (redundant) EGC. Consequently, an insulated (anti- short) bushing is required required at all Type AC terminations (320.40). The insulated bushing is not required for Type MC (Art. 330).

Take your pick

Southwire's HCF MCCAP is in fact a MC type cable.
http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet2

Their AC HCF cable is an AC type cable.
[url]http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet260
[/URL]

 

[roger]

I agree entirely with Roger's analysis of this issue - exactly identical to that which an electrical contractor friend of mine faced two weeks ago. The question was whether he could install traditional MC cable (with a green insulated wire-type EGC, but without the sheath being approved as an EGC) as a wiring method to luminaires located more than 71/2 feet above the floor. The state electrical supervisor surprisingly ruled YES: he said that that wiring method was superior to one in which only the cable sheath was approved as an EGC. I agree with him, but that is not what the Code seems to say. Perhaps for the 2020 Code cycle a proposed change to 517.13(B)(1) Ex No.2 to (3) would be in order?

Kevin, actually the conduit combined with all the other metal in hospital construction methods make the conduit the better / primary EGC.

Commentary from the NFPA 99 (I think it is A 6.4.3.3.1.3 in the latest NFPA 99)

NFPA 99 A 4.3.3.1.3

The performance of the grounding system is made effective through the existence of the green grounding wire, the metal raceway, and all of the other building metal. Measurements have shown that it is the metal raceway and building steel that provide most of the effective grounding path of less than 10 milliohms at the receptacle, including plug to receptacle impedance. The green grounding wire becomes a backup, not a primary path performer.

Roger

 

[augie47]

It doesn't comply with the redundant ground aspect, but I'm referring to this section:

517.13 Grounding of Receptacles and Fixed Electrical Equipment in Patient Care Areas

Wiring in patient care areas shall comply with 517.13(A) and (B).

(A) Wiring Methods. All branch circuits serving patient care areas shall be provided with an effective ground-fault current path by installation in a metal raceway system, or a cable having a metallic armor or sheath assembly. The metal raceway system, or metallic cable armor, or sheath assembly shall itself qualify as an equipment grounding conductor in accordance with 250.118.


On the spec sheet, it says:

Grounding One grounding means - Combinedarmor and full-sized aluminumground/bond conductor NEC®250.118(10)(b)

Looks to me like the MC cable complies with 517.13 (A). Do you agree?

I do not find it acceptable for Art 517 installations for two reasons: (1) It does not list Art 517 and (2) It states "one grounding means". The diagram makes one think it is Heath Care but written indicators say "no".
Compare your cut sheet to this AFC product that is definitely Health care Art 517
http://www.afcweb.com/mc-metal-clad-cables/mc-stat-lite-cable/

 

[kwired]

Until they came out with MC-AP or other equivalent brands, I don't believe there was MC cable that met art 517 requirements and everyone was using AC cable with an insulated EGC.

MC-AP (and equivalents) is nearly same thing as AC cable but doesn't have paper fillers/spacers. To meet art 517 requirements still needs to contain an insulated EGC.