Can anyone tell me in what situations you actually need the bonding jumper on the outside of lfmc or fmc I see it everywhere in my plant and other plants Ive been to. It seems redundant to me when everything has a ground run to it anyways can anyone explain or give me examples or code articles?
Bonding jumper outside of flex
- Thread starter kjroller
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician
It's generally not required but for whatever reason electricians seem to think that it is. For years we would have guys putting them on FMC at transformers. Never the correct size and typically attached to the clamping screw for the FMC.
Is there any instance it is required I know big contractors that always do it but I always run a EGC with my wires anyway so I never understood it.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If there is no EGC's within the raceway and the flex doesn't qualify as an EGC then something is required. I haven't seen many field installed bonding jumpers around FMC that were done correctly. If there is an EGC in the raceway I can't think of a scenario where the jumper is required. Having said that someone may come up with one.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
I had a 50 hp 460 volt motor fed with #4 THW in 1” RMC under the slab I would have preferred to pull in THHW/N but that THW was stuck. I ran 1” LTMC with external bonding fittings that T&B makes. Worked great. The picture of this is in Mike grounding book
Would 501.30 B2 or 502.30 B2 be an example of where I need a external or internal bonding jumper and the EGC does not satisfy the requirements?
This is new to the 2023 code from what I can tell
- Location
- Illinois
- Occupation
- retired electrician
Most plans and specs for industrial installations in my area will require both a wire type EGC in the raceway and a bonding jumper around any LFMC in a power circuit.
- Location
- Illinois
- Occupation
- retired electrician
I can see how you could read 501.30(B) to require a bonding jumper for LFMC installed in a classified area, but it stops short of actually saying that. All of my classified area work has been in industrial plants where the specs have always required the use of an external bonding jumper for all LFCM used with power circuits, even where the area was not classified.
This is not really a new requirement for the 2023. Just marked as new because the section was re-organized. There is no new requirements.
I guess I am confused because it says it shall comply with 501.30 B 2a and B 2b so wouldn't that make it required? The way I guess I'm reading it is the only way it isn't required is if the conditions are met.
- Location
- Illinois
- Occupation
- retired electrician
You are correct...I did not read all of the section.
Thank you for your input highly appreciated! 90% of what I run across is still extra for sure but just wanted to confirm.
Fred B
Senior Member
- Location
- Upstate, NY
- Occupation
- Electrician
Question. As a substitute for an internal EGC bonding wire within the flex (either because fill or not easily pulled thru or retro fit) can a bonding wedge be used on the exterior of connector and enclosure and a wire bonding jumper to electrically connect both ends of the flex?