Flex on the Critical Branch

[MEP_PM]

In a new hospital project an under counter light in a patients room was added to the project prior to drywall installation and cabinet installation. This was roughed in to a nearby critical circuit with hospital grade MC. Now the question has been asked if this meets code requirements.

In reviewing 517.30(C)(3) there are several exceptions that allow for the use of MC on the critical branch. (d) allows it where necessary to connect to equipment. If you refer the NEC definition of equipment you will find that a light is considered equipment. So if the question is if the word ?equipment? can be used to refer to a light. The answer per NEC definition is yes.

That leaves the argument on the interpretation of the word necessary. This word in not defined in the NEC. So an argument would need to be developed to show why this is necessary to the installation. For example: Flexibility is needed to fish the raceway in the cabinet. Hard pipe would not allow for the installation of the cabinets. The final or exact location of the light or the cabinet has not been determined so flexibility is needed.

What are your thoughts? Do you think the use of MC is acceptable in this installation?

 

[lowryder88h]

Flex

Flex

I think its fine, 517.12 wiring methods, 517.13 (A) (B)

 

[roger]

I think its fine, 517.12 wiring methods, 517.13 (A) (B)

Lowrider, you have to look at 517.30(C)(3) for this.

(3) Mechanical Protection of the Emergency System The wiring of the emergency system in hospitals shall be mechanically protected. Where installed as branch circuits in patient care areas, the installation shall comply with the requirements of 517.13(A) and 517.13(B). The following wiring methods shall be permitted:

(1) Nonflexible metal raceways, Type MI cable, or Schedule 80 rigid nonmetallic conduit. Nonmetallic raceways shall not be used for branch circuits that supply patient care areas.

(2) Where encased in not less than 50 mm (2 in.) of concrete, Schedule 40 rigid nonmetallic conduit, flexible nonmetallic or jacketed metallic raceways, or jacketed metallic cable assemblies listed for installation in concrete. Nonmetallic raceways shall not be used for branch circuits that supply patient care areas.

(3) Listed flexible metal raceways and listed metal sheathed cable assemblies in any of the following:
a. Where used in listed prefabricated medical headwalls
b. In listed office furnishings
c. Where fished into existing walls or ceilings, not otherwise accessible and not subject to physical damage
d. Where necessary for flexible connection to equipment

(4) Flexible power cords of appliances or other utilization equipment connected to the emergency system.

(5) Secondary circuits of Class 2 or Class 3 communication or signaling systems

MEP_PM, we always use flexible wiring methods for this installation and it is allowed by our inspectors, but, it could be argued that with proper coordination this could be done in a non-flexible metallic wiring method.

Roger

 

[MEP_PM]

Rogers,
I have never had a problem either before this job. The local inspector originally passed it and then the hospital staff questioned the installation. Now the inspector has taken a step back and wants the Hospital to sign off on the installation as well. So, it?s becoming a mess. I think we are planning to discuss this with the State Hospital inspector. If the state inspector will approve it, I think the local inspector will also accept it. I guess we will see what happens.

 

[kfenn22]

I don't think you should have a problem with using Flex, But I can see them have an issue that an under counter light being on a critical ckt.

You might want to look at AIA Hopsitpal code. (if applied in your state.)

Had a issue a few years ago with critical ckts and non-patient lights.
The inspector told us that light on critical ckts need to for patient care only not task lights.

But, if you look up article 517.2 definitions critical branch: it allows task illuminations.

Needless to say we had to move the undercounter light to normal power.

 

[roger]

But I can see them have an issue that an under counter light being on a critical ckt.

There is no issue, the task illumination is chosen by the user and if the EPSS was large enough all the hospitals loads (excluding the Equipment loads and mandatory Life Safety Loads) could be served by the Critical branch

You might want to look at AIA Hopsitpal code. (if applied in your state.)

There is nothing in the AIA design guidelines prohibiting this.

Had a issue a few years ago with critical ckts and non-patient lights.
The inspector told us that light on critical ckts need to for patient care only not task lights.

Unless it's a local code the inspector was wrong.

But, if you look up article 517.2 definitions critical branch: it allows task illuminations.

And so does 517.33(A) as well as NFPA 99 4.4.2.2.2.3

Needless to say we had to move the undercounter light to normal power.

That probably kept the peace with this inspector.

Roger