Electrical Engineer here. I have had this discussion at work and am trying to wrap my head around it.
Design and build custom machinery for sale in North America. Use the NEC as a basic guideline for sizing conductors and overcurrent protection. Using fine stranded large gauge conductors for power distribution to certain loads. High stand count cable is desired for flexibility during installation and service. Standard crimp lugs are not UL listed for high strand count conductors. Have been using them in this application for years with no history of problems.
Question is: Where does the NEC _REQUIREMENTS_ stop? I say the NEC stops at the system disconnect. Everything past that is the machinery manufacturer's decision.
Another example: RG 175 is UL listed for 35 V. We routinely run 800-1000 VDC thru it for X-Ray detectors. Catalog lists it for use up to 1000V. Are we violating the NEC?
If it were Europe the manufactured equipment would be covered by a whole range of technical standards, covering safety, emc, ergonomics, etc and would be certified by its maker against these, with no reference to building standards other than the required supply. I would be surprised if it was much different on your side of the water. Certainly USA manufactured gear imported to UK has worked like this.
#217887 - 12/28/1611:15 AMRe: Custom machine. Where does NEC requirements stop?
Larry, if the equipment is maunfactured in "an engineered controlled environment", then the NEC does not apply. The NEC is for new construction. All electrical equipment must be listed OR approved. Listing is not required for custom built equipment however the customer may require it if local ordinance does not. In your case, NEC 409, 725, and NFPA 79? may be applicable. Others may apply as well
Last edited by sparkyinak; 12/29/1604:45 AM.
"Live Awesome!" - Kevin Carosa
#217889 - 12/29/1602:24 PMRe: Custom machine. Where does NEC requirements stop?
Once all of the building permits are closed you will be dealing with the Fire/Life Safety officer and YMMV about how closely they are looking at installed equipment. I agree with John, having a NRTL sticker on it will pretty much make further inspection go away unless there is a fire. Repairing and modifying a listed box may have some legal ramifications but I have not seen it in real life. The lawyers told us we could not legally change a plug cap on a line cord (listing issues) but we still had a part number and we could order them.
The type of equipment I am talking about is large capital equipment. It may have multiple power sources, it may be in several rooms, it may be outside. It may be for medical use, facility security, or factory automated manufacturing. I am just trying to understand where one set of requirements stop and the next set begin.
I'm looking for the equivalent of the demarcation point that separates the phone company equipment from the building's equipment.
If the equipment is manufactured in "an engineered controlled environment", then the NEC does not apply.
I interpret that to mean, If we design and build it, and then oversee the installation of it in your facility, the NEC applies up to the Main disconnect(s) and everything past that falls on the machine designer/builder.
If there are multiple equipment cabinets connected to sub assemblies and each other, by cables laying in dedicated cable trays, are the cables subject to NEC requirements too? The power flowing thru the cable tray cables come from power supplies that are downstream of the disconnects.
Thanks for all of the replies so far.
#217892 - 12/30/1603:10 AMRe: Custom machine. Where does NEC requirements stop?
Larry: The second part of your reply basically falls into the following scenario:
Cabling from one piece of equipment to other equipment of the same system, in trays, would require 'listed' trays, bonding, and cabling. The methods and materials used to terminate cabling may have a 'look' by an inspector. IF the cabling is 'plug & play' type, I would just give it a glance, as it would be out of the NEC boundries.
Please note that the opinions herein are my personal opinions, based on guidelines within the NJ UCC, and may be different in other jurisdictions.
A 'short' wording of the regs is 'process equipment stops at the disconnects of the feeder at the equipment, and the fees imposed are only for the feeder and disconnect if it is NOT within the equipment. However ALL 'parts' of said system that are hard wired (NEC) are required to be within the permit app, and appropriate fees and inspections are required. (My words and not a direct quote)
Determination within my jurisdiction is part of the plan review, release, and permit issuing process.