NEC Code

[Biomedical]

The electrical inspector failed a room installation (Fixed C-arm angio- system) at our facilities. All the vendor supplied systems cables are routed through conduits below the computer floor and in the ceiling. He states the following: " Cables installed between machines, if not a listed wiring method listed in the 2020 NC State Electrical code or have a field evaluation conducted by an approved 3rd party testing agency recognized by NCDOI". Please assist as we can't use the system until he approves.

 

[tom baker]

Are the vendor cables shown on the machine drawings or BOM? If so they could be part of the machine.
I have installed flow meters with factory cables that are not UL listed, so your issue is not unique

 

[Biomedical]

Are the vendor cables shown on the machine drawings or BOM? If so they could be part of the machine.
I have installed flow meters with factory cables that are not UL listed, so your issue is not unique

Yes, all the cabling are in the OEM documents if I understood correctly. The drawings from the Town approval and permits it showed the cabling routing through conduits which they approved

 

[roger]

I agree with Tom. The machine should be listed as an assembly and the cables are under the listing. The inspector is probably not versed in inspecting medical equipment.

 

[augie47]

Is the machine and control UL or other NRTL approved ?
If so, and it was all OEM supplied, I agree it should be approved as an assembly.

 

[roger]

Yes, all the cabling are in the OEM documents if I understood correctly. The drawings from the Town approval and permits it showed the cabling routing through conduits which they approved

You might contact the state for their assistance

State Electrical Division Contacts | OSFM

How to contact the North Carolina State Electrical Division

www.ncosfm.gov

 

[tom baker]

In Washington we have a state rule that exempts medical equipment…it may be permits etc, due to a federal law.

 

[tortuga]

I'd say this is one of the slippery areas where a UL listing can try to pave over the code but wont get far unless there is a state law citing other wise, like apparently WA has. Seems like there can be too many installation variations for the listed system to cover all bases.

 

[roger]

I'd say this is one of the slippery areas where a UL listing can try to pave over the code but wont get far unless there is a state law citing other wise, like apparently WA has. Seems like there can be too many installation variations for the listed system to cover all bases.

All of this type equipment will come with detailed design drawing specific to each installation and the field wiring verses machine wiring is defined. IOW's, after the field installed lighting, receptacles, and machine disconnect, the machines wiring and its installation is not an inspectors concern.

In the many medical installations I did the inspectors wanted a copy of the room commissioning report for records but understood the machines were outside the NEC.

 

[tortuga]

the machines wiring and its installation is not an inspectors concern.

As long the machines wiring does not leave the machine its not.
As soon as it dives in a conduit, tray or other raceway where it can affect the building it needs to be a chapter 3 wiring method in my opinion.

 

[steve66]

As long the machines wiring does not leave the machine its not.
As soon as it dives in a conduit, tray or other raceway where it can affect the building it needs to be a chapter 3 wiring method in my opinion.

Its typical for medical imaging equipment to have cables between parts of the equipment. For example, between the control console behind a X-ray shield and to an X-ray table or wall Bucky.

They are cables, and not “conductors” therefore a chapter 3 method is not required. And who knows if it’s high voltage, Line voltage, or class 1,2 or 3, or just data and comm cables.

the medical imaging companies have designed these systems and they have deep pockets if anything happens, so you can be sure they aren’t skimping on safety. They specify cable trays, wireways and conduits anywhere where safety might be an issue.

 

[tortuga]

the medical imaging companies have designed these systems and they have deep pockets if anything happens, so you can be sure they aren’t skimping on safety.

If the depth of corporate pockets had a 1 to 1 relationship with electrical safety or safety in general I think there are allot of things we could take out of the code. Probably just do away with the code all together.

Buildings like a hospital can last over 100 years, companies come and go. It sets a dangerous precedent for UL or some listing agency to just overwrite code. Even listing labs come and go. Think about that.

If their listed system is mm2 wire, some metric non-standard conduit, blue neutrals and all the IEC color codes then whats to stop a lighting manufacturer or any manufacture from proposing a similar listed system for something else? The manufacturer gets denied then they sue the state when they get denied, citing equal protection under the law? When do you stop carving out special cases for corporations ?

I here you, and I know about this weird exemption they have tried to carve out for themselves, but I respectfully disagree with it only applying to them, the law has to be applied equally and the code is the law.
The AJH is within their rights to require wiring between equipment to be a chapter 3 wiring method.
I just don't see a compelling case to carve out a huge exception for wiring methods to interconnect one type of equipment, unless they do it in the code with a special chapter.

 

[roger]

The AJH is within their rights to require wiring between equipment to be a chapter 3 wiring method.

What chapter three method covers 50KV cables?

 

[tortuga]

What chapter three method covers 50KV cables?

Same section that covers blue neutrals 90.2 (A) and 90.4

 

[roger]

Neither of those has anything to do chapter three wiring methods.

With that said read 90.3 and notice article 90 is not even mentioned in the code arrangement. Article 90 is simply and introduction and no different than an FPN or IN.

90.4 only explains that the AHJ can interpret items that are under the NEC and if they aren't then all they can request is to see the listing and commissioning of the machine and room it is contained in. This is a lot like the Master Label on a lightning protection system, the only thing that would be a concern to an EI is where the lightning Protection System connects to the GES.

Unless you can somehow get article 517 to expand and specifically cover all the small details associated with CT scans, MRI's, Linear Accelerators, Pet Scan rooms, Nuclear Medicine rooms, etc .... there is no way the NEC can apply to every item. There is some wording in NFPA 99 that covers some of this as well.

 

[tortuga]

Neither of those has anything to do chapter three wiring methods.

90.2(A) is the scope of the code, and the scope of the NEC covers all parts of a hospital. I dont see anything in 90.2(B) that would exempt the installation the OP describes. (other than special permission 90.4)

Article 90 is simply and introduction and no different than an FPN or IN.

Incorrect 90 is part of the code and enforceable.

 

[tortuga]

And I'll add 90.4 'special permission' probably involves "a field evaluation conducted by an approved 3rd party testing agency".
In other words the only way around the implied 35000 volt or any other limitations carved out in 300.1(A) is 300.1(B) or 90.4 special permission.

 

[roger]

90.2(A) is the scope of the code, and the scope of the NEC covers all parts of a hospital. I dont see anything in 90.2(B) that would exempt the installation the OP describes.

Incorrect 90 is part of the code and enforceable.

90.2(A) is not talking about a machine. What you're not realizing is that even though there are field installed raceways the working components are part of a listed machine. Since you're so into article 90 see 90.7



You didn't read 90.3 did you?

90.3 Code Arrangement. This Code is divided into the
introduction and nine chapters, as shown in Figure 90.3.
Chapters 1, 2, 3, and 4 apply generally; Chapters 5, 6, and
7 apply to special occupancies, special equipment, or other
special conditions. These latter chapters supplement or modify
the general rules. Chapters 1 through 4 apply except as
amended by Chapters 5, 6, and 7 for the particular conditions.
Chapter 8 covers communications systems and is not subject
to the requirements of Chapters 1 through 7 except where
the requirements are specifically referenced in Chapter 8.
Chapter 9 consists of tables that are applicable as referenced.
Informative annexes are not part of the requirements of
this Code but are included for informational purposes only.

You have an introduction and 9 code chapters.

Once again, where is 50KV cables listed in chapter three wiring methods?

 

[tortuga]

Once again, where is 50KV cables listed in chapter three wiring methods?

Once again the same chapter that allows a blue neutral, none they are prohibited unless you obtain special permission 90.4

 

[roger]

Once again the same chapter that allows a blue neutral, none they are prohibited unless you obtain special permission 90.4

You aren't getting it, the cables are already approved and the NEC has no say in the matter, see 90.7.

If this bothers you you should submit a proposal. Note that in these types of rooms there are other agencies that have the final say in approving the installations such as DHHS and NCRP.