exposed MC cable in boiler rooms

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JEI

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I recently re wired a boiler room. It looked liked the plumber did it originally in exposed MC cable. He had MC hooking up the old boiler and thought that I would just reuse it. I told him it was not code to wire a boiler with exposed MC, you would have to use steel flex from the disconnect. code book isnt to clear to me. Was I right? Ive always used flex in that situation? Thanks for your help!
 
JEI said:
I recently re wired a boiler room. It looked liked the plumber did it originally in exposed MC cable. He had MC hooking up the old boiler and thought that I would just reuse it. I told him it was not code to wire a boiler with exposed MC, you would have to use steel flex from the disconnect. code book isnt to clear to me. Was I right? Ive always used flex in that situation? Thanks for your help!
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330.10 Uses Permitted.
(A) General Uses. Type MC cable shall be permitted as follows:

  1. For services, feeders, and branch circuits.
  2. For power, lighting, control, and signal circuits.
  3. Indoors or outdoors.
  4. Exposed or concealed.
  5. To be direct buried where identified for such use.
  6. In cable tray where identified for such use.
  7. In any raceway.
  8. As aerial cable on a messenger.
  9. In hazardous (classified) locations where specifically permitted by other articles in this Code.
  10. In dry locations and embedded in plaster finish on brick or other masonry except in damp or wet locations.
  11. In wet locations where any of the following conditions are met:
    1. The metallic covering is impervious to moisture.
    2. A moisture-impervious jacket is provided under the metal covering.
    3. The insulated conductors under the metallic covering are listed for use in wet locations, and a corrosion-resistant jacket is provided over the metallic sheath.
  12. Where single-conductor cables are used, all phase conductors and, where used, the grounded conductor shall be grouped together to minimize induced voltage on the sheath.
 
yes. sounds like the plumber was right. I always went on the assumption that surface mounted in that situation would be subject to physical damage.
In San Francisco there must be a by law that you cant use it. I have had electrical inspectors make us use flex to furnaces in houses that were done in MC from the disconnect. Also in kitchen islands, were we have to surface mount, we cant use it. This boiler was in marin county.

330.12
(1) where subject to physical damage ???
 
JEI said:
yes. sounds like the plumber was right. I always went on the assumption that surface mounted in that situation would be subject to physical damage.
In San Francisco there must be a by law that you cant use it. I have had electrical inspectors make us use flex to furnaces in houses that were done in MC from the disconnect. Also in kitchen islands, were we have to surface mount, we cant use it. This boiler was in marin county.

330.12
(1) where subject to physical damage ???
Click to expand...

SF is one of those places that had some really strict local codes for years. Union protectionism mostly. Shoot they didn't even have a McDonald's in SF until I think it was the 1980's. I think I remember my Mentor a Mr. John Oliva Sr. telling me that romex and MC weren't allowed at all in residences for many years. I think an AHJ would be hard pressed to prove that steel cased MC was more subject to damage than aluminum flex, or really even steel flex. In most of the surrounding areas, MC is exactly what they require to be run exposed in garages and basements.
 
JEI said:
...
330.12
(1) where subject to physical damage ???
Click to expand...
Type MC cable, in all its forms (interlocked, smooth and corrugated armor), meet the same UL crush and impact tests as FMC and LFMC. They also have the same, “Where subject to physical damage”, restriction. In other words, if you would accept FMC or LFMC exposed, there’s no valid reason to reject MC.

Actually, so does TC-ER, but the crush/impact tests permit a certain failure rate and MC, FMC and LFMC always surpass without any failures. On rare occasions TC-ER fails but well within the accepted rate. It has other restrictions that prohibit it from being used but where NM is acceptable. IMO the reasons are commercial, not safety.
 
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rbalex said:
Type MC cable, in all its forms (interlocked, smooth and corrugated armor), meet the same UL crush and impact tests as FMC and LFMC. They also have the same, ?Where subject to physical damage?, restriction. In other words, if you would accept FMC or LFMC exposed, there?s no valid reason to reject MC.

Actually, so does TC-EL, but the crush/impact tests permit a certain failure rate and MC, FMC and LFMC always surpass without any failures. On rare occasions TC-EL fails but well within the accepted rate. It has other restrictions that prohibit it from being used but where NM is acceptable. IMO the reasons are commercial, not safety.
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Nice info.:thumbsup: Bookmarked. Thanks.
 
Musings from the house plumber...

Musings from the house plumber...

JEI said:
yes. sounds like the plumber was right. I always went on the assumption that surface mounted in that situation would be subject to physical damage.
In San Francisco there must be a by law that you cant use it. I have had electrical inspectors make us use flex to furnaces in houses that were done in MC from the disconnect. Also in kitchen islands, were we have to surface mount, we cant use it. This boiler was in marin county.

330.12
(1) where subject to physical damage ???
Click to expand...

I thought all of us plumbers were always right...
Seriously though....I've always used MC to run between the discon and boiler/furnace/air handler, never got rejected.
 
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