MC Cable in Patient Care Areas

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nd99

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The 2002 NEC, Section 517.13 (A) indicates that "...MC Cable...shall have an outer metal armor or sheath that is identified as an acceptable grounding return path."

Has the common corrugated MC cable been declared unsuitable for patient care areas since the 2002 NEC? Thanks.
 
Re: MC Cable in Patient Care Areas

Originally posted by nd99:
Has the common corrugated MC cable been declared unsuitable for patient care areas since the 2002 NEC? Thanks.
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The 'common corrugated MC cable' has never been allowed in patient care areas.

That type of MC provides only one ground fault path.

What is allowed is hospital grade AC cable which has an armor suitable for grounding and an insulated grounding conductor.
 
Re: MC Cable in Patient Care Areas

Corrugated is not the common type. The common type is spiral interlocking metal tape. The corrugated type and the smooth type are both OK, but I am not sure that they are still manufactured.
 
Re: MC Cable in Patient Care Areas

Sorry, I used the wrong wording.

What year did it become code that spiral interlocking MC Cable cannot be used in patient care areas?
 
Re: MC Cable in Patient Care Areas

I only have my code books back to the 1990 edition here at work and it was stated in 517-13(b) that the outer metal jacket of Type MC had to be an approved grounding means of a Listed assembly.

The 93 cycle cleared up the wording to what is the present wording.
The metal raceway system, or metallic cable armor, or sheath assembly shall itself qualify as an equipment grounding return path
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This would eliminate common interlocking MC as far back as then.

Roger

[ January 30, 2006, 01:08 PM: Message edited by: roger ]
 
Re: MC Cable in Patient Care Areas

"MC" is allowable only if the connectors are approved as "suitable" for gounding. This can be found on the box or label the connectors came from.
 
Re: MC Cable in Patient Care Areas

To me, the best answer is found in the UL green book listing for MC cable (PJAC)
The sheath of the smooth or corrugated tube type MC cable or a combination of the sheath and a supplemental bare or unstriped green insulated conductor is suitable for use as the required quipmenmt grounding conductor.
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This rules out the common, interlocked metal tape MC as a grounding coductor itself, and since the COMBINATION of the sheath and conductor is A equipment ground, those cables do not provide REDUNDANT grounding.

[ January 30, 2006, 03:06 PM: Message edited by: augie47 ]
 
Re: MC Cable in Patient Care Areas

THANK YOU Roger for the research & to the others that replied to my question. The information helped clear up a problem.
 
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