# dentist office



## mjjg92 (Jan 19, 2012)

Running a circuit to an xray machine which is located in the hallway of a dental office ,not in a patient care room. Am I required to use Hospital Grade MC cable ? Its going to a 20 amp 240 V wall receptacle.


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## Speedy Petey (Jan 10, 2007)

IMO yes, definitely. It is still patient care equipment.


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## Celtic (Nov 19, 2007)

Are they planning on wrapping the hallway with lead?


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## Bbsound (Dec 16, 2011)

Its probably the unit that spins around the head and has a shield on the opposite side of the emitter.


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## tates1882 (Sep 3, 2010)

mjjg92 said:


> Running a circuit to an xray machine which is located in the hallway of a dental office ,not in a patient care room. Am I required to use Hospital Grade MC cable ? Its going to a 20 amp 240 V wall receptacle.


Any equipment that the patient interacts with needs to "double or redundant" ground. I.e. emt with a ground or med grade mc or ac cable.


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## papaotis (Jun 8, 2013)

nec-wise, yes ,code-wise it depends on where you are and what type of building, i.e., a strip mall may not require it


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## papaotis (Jun 8, 2013)

something i have never quite understoodis why the armor in armored cable is not accepted as a ground. it is a continuos thread of metal, just like a wire, and connected right, its always there!:001_huh:


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## Celtic (Nov 19, 2007)

papaotis said:


> something i have never quite understoodis why the armor in armored cable is not accepted as a ground. it is a continuos thread of metal, just like a wire, and connected right, its always there!:001_huh:


The sheath of Type AC is listed as an EGC

250.118(8)
320.108


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## papaotis (Jun 8, 2013)

Celtic said:


> The sheath of Type AC is listed as an EGC
> 
> 250.118(8)
> 320.108


 why not mc? its the same thing only lighter?:001_huh:


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## Celtic (Nov 19, 2007)

papaotis said:


> why not mc? its the same thing only lighter?:001_huh:


Some MC is listed as an EGC [250.118(10)], but not all.
It is important to recognize the difference ~ which you will notice instantly based on price. :laughing:




2011 NEC said:


> 250.118 (10) Type MC cable that provides an effective ground-fault current path in accordance with one or more of the
> following:a. It contains an insulated or uninsulated equipment grounding conductor in compliance with 250.118(1)
> b. The combined metallic sheath and uninsulated equipment grounding/bonding conductor of interlocked metal tape–type MC cable that is listed and identified as an equipment grounding conductor
> c. The metallic sheath or the combined metallic sheath and equipment grounding conductors of the smooth or corrugated tube-type MC cable that is listed and identified as an equipment grounding conductor​



...like wise, not all Type AC is listed as an EGC, but you would be requesting an oddball product that would probably be out of line with what you would expect to pay.


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## Celtic (Nov 19, 2007)

*The Most Asked Questions about Type AC and MC Cable*



...see items #7 & 18


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## papaotis (Jun 8, 2013)

thanks, 18 doesnt answer my question about mcit has a continuos wire, asually #12 that should make it at least as good a egc as ac?


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## Celtic (Nov 19, 2007)

papaotis said:


> thanks, 18 doesnt answer my question about mc


It is pointing out the difference between AC and MC, so it does answer/relate to the question.:whistling2:




papaotis said:


> it has a continuos wire, asually #12 that should make it at least as good a egc as ac?


Of course the #12 EGC is "as least as good as ac" with a #16 bonding strip.

MC and AC are NOT same....completely different products - although some permitted uses do overlap - is the not permitted applications that usually get people a red sticker [330.12 vs. 320.12]


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## Speedy Petey (Jan 10, 2007)

A fault in MC cable sheathing will follow the spiral of the sheath. It will not go linearly down the cable. This makes that conductor extremely long and a much higher resistance. 

The bonding strip in AC cable bonds each spiral to make the sheathing act as a linear conductor.


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## Speedy Petey (Jan 10, 2007)

Speedy Petey said:


> A fault in MC cable sheathing will follow the spiral of the sheath. It will not go linearly down the cable. This makes that conductor extremely long and a much higher resistance.
> 
> The bonding strip in AC cable bonds each spiral to make the sheathing act as a linear conductor.


HCF (health care facility) cable incorporates both the bond strip and a green insulated ground which creates the redundant ground path.


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## papaotis (Jun 8, 2013)

so the way im seeing this is mc is actually better!and easier to use:thumbsup:


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## papaotis (Jun 8, 2013)

sorry, pete was typing and get your reply in time. THANKS, now i get itafter some more thought, im guessing that theory behind that is the al wire will stay in contact with the sheath, or at least enough to make a much shorter path?


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## Celtic (Nov 19, 2007)

papaotis said:


> so the way im seeing this is mc is actually better!and easier to use:thumbsup:



IMHO, MC has many more uses than AC. 
As far as ease of use/installation..in that aspect, they are exactly the same. 
The caveat is cost ~ that extra Cu conductor isn't free!


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## hardworkingstiff (Jan 22, 2007)

Speedy Petey said:


> The bonding strip in AC cable bonds each spiral to make the sheathing act as a linear conductor.


If there was a lightning strike and that AC cable took a hit, I wonder if there would be a good chance of that bonding strip (pretty thin aluminum) would have a point it burnt in two? If it did, how would we ever know?


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## manchestersparky (Mar 25, 2007)

papaotis said:


> nec-wise, yes ,code-wise *it depends on where you are and what type of building, i.e., a strip mall may not require it*


If the panoramic x-ray is used to x-ray a person it becomes a health care area

look at the definitions in 517 ( underlining is mine) 


*Health Care Facilities. 
*Buildings or portions of buildings in which medical, dental, psychiatric, nursing, obstetrical, or surgical care are provided. Health care facilities include, but are not limited to, hospitals, nursing homes, limited care facilities, clinics, medical and dental offices, and ambulatory care centers, whether permanent or movable.

*Patient Care Area. *​*
*​*
*Any portion of a health care facility wherein patients are intended to be examined or treated. Areas of a health care facility in which patient care is administered are classified as general care areas or critical care areas. The governing body of the facility designates these areas in accordance with the type of patient care anticipated
and with the following definitions of the area classification.​ 
​​Informational Note: Business offices, corridors, lounges,
day rooms, dining rooms, or similar areas typically are not
classified as patient care areas.​

​​​​​


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