2008 517.13(B), Exception No. 2 -- Question?

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tx2step

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North Texas, DFW area
We're doing a new medical clinic building -- no specs, one electrical drawing showing only receptacle outlet locations, one reflected ceiling plan showing light fixture locations -- otherwise, just building floor plans & elevations to work with. There are 10 "Exam Rooms" which I believe are "Patient Care Areas". There's no generator & no "Critical Care" or "Wet Procedure" areas, and no "Essential Electrical System". There are no "Pediatric Locations". 517.18(A), Exception No. 2 would apply. The 2008 NEC applies.

For the 120V receptacle wiring in the "Exam Rooms" I'll be using Southwire HCF-MCAP type, green MC cable, #12/2 with ground.

But I'm a little confused by 517.13(B), Exception No. 3. The ceiling height is 9 feet & the lights will be surface mount 4 lamp wrap around 32W T8 florescent fixtures. But it appears that 517.13(A) will still apply to the fixture wiring, which requires that the "medical cable armor or sheath assembly shall itself qualify as an equipment grounding conductor in accordance with 250.118."

That would appear to me to eliminate using standard type "MC" cable, since it's metal armor is not the ground -- it has a green insulated ground wire inside of it. If I want to use cable, that would leave me with type "AC" cable, which none of my suppliers stock, and would cost about the same as the HCF-MCAP anyway.

So if I want to use cable, it looks like I'm stuck using HCF-MCAP for the Exam Room lighting too?

Am I missing something?

Is there anything else I should watch out for in a new, plain medical clinic building?

Thanks!
 
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tx2step

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North Texas, DFW area
Oops... I forgot to say the branch wiring in the rest of the building will be done with standard MC cable, except that I'll use 1/2" EMT & #12 THHN for the 3-way switching.

Anything else that I should watch out for?

Thanks!!!
 
roger

roger

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tx2step said:
We're doing a new medical clinic building -- no specs, one electrical drawing showing only receptacle outlet locations, one reflected ceiling plan showing light fixture locations -- otherwise, just building floor plans & elevations to work with. There are 10 "Exam Rooms" which I believe are "Patient Care Areas". There's no generator & no "Critical Care" or "Wet Procedure" areas, and no "Essential Electrical System". There are no "Pediatric Locations". 517.18(A), Exception No. 2 would apply. The 2008 NEC applies.

For the 120V receptacle wiring in the "Exam Rooms" I'll be using Southwire HCF-MCAP type, green MC cable, #12/2 with ground.

But I'm a little confused by 517.13(B), Exception No. 3. The ceiling height is 9 feet & the lights will be surface mount 4 lamp wrap around 32W T8 florescent fixtures. But it appears that 517.13(A) will still apply to the fixture wiring, which requires that the "medical cable armor or sheath assembly shall itself qualify as an equipment grounding conductor in accordance with 250.118."

That would appear to me to eliminate using standard type "MC" cable, since it's metal armor is not the ground -- it has a green insulated ground wire inside of it. If I want to use cable, that would leave me with type "AC" cable, which none of my suppliers stock, and would cost about the same as the HCF-MCAP anyway.

So if I want to use cable, it looks like I'm stuck using HCF-MCAP for the Exam Room lighting too?

Am I missing something?

Is there anything else I should watch out for in a new, plain medical clinic building?

Thanks!
Click to expand...

You are not missing anything, you are correct in your interpretation.


Roger
 
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tx2step

Senior Member
Location
North Texas, DFW area
Joe Villani said:
Tx2step,

Why not use regular MCAP?

Why would you need the HCF type?

The Sheath is the ground.

Joe Villani
Click to expand...

I didn't know that regular MCAP had a sheath that qualified as a the ground -- I thought it was regular MC cable with an internal ground wire. Does it have a bare ground wire that's in contact with the sheath for the length of the cable?
 
steve66

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Joe Villani said:
Tx2step,

Why not use regular MCAP?

Why would you need the HCF type?

The Sheath is the ground.


Joe Villani
Click to expand...

Regular MCAP cable wouldn't meet the redundant grounding requirments of 517.13 (A) and (B). (B) requires an additional insulated grounding conductor, in addition to the sheath.
 
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tx2step

Senior Member
Location
North Texas, DFW area
steve66 said:
Regular MCAP cable wouldn't meet the redundant grounding requirments of 517.13 (A) and (B). (B) requires an additional insulated grounding conductor, in addition to the sheath.
Click to expand...

That's true, except that lighting above 7'-6" only has to comply with 517.3(A). See 517.13(B), exception No. 2.

However, the switches are located at 44" and are in the exam rooms, so they'll have to be HCF-MCAP. Would that also mean that the lighting circuit wiring all the way back to the panel would have to be HCF-MCAP to give you redundant grounding back to the panel -- because of the switch legs being in the "Patient Care Area"??? It would seem to me that it would, but that's why I am asking the question. =:)

I've been using Southwire Alumiflex MC cable & paying about $96 per 250' roll. How much does regular MCAP normally cost?

Thanks!!!
 
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