250.118

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I think it depends largely on the transition from one method to another and wheather or not the fittings are listed for such ....Is this what you are driving at ?
 
I'm thinking the IMC won't be bonded correctly with FMC on one side and LFNC on the other.

250.118(5) Listed flexible metal conduit meeting all the following conditions:
a. The conduit is terminated in listed fittings.
b. The circuit conductors contained in the conduit are protected by overcurrent devices rated at 20 amperes or less.
c. The combined length of flexible metal conduit and flexible metallic tubing and liquidtight flexible metal conduit in the same ground return path does not exceed 1.8 m (6 ft).
d. Where used to connect equipment where flexibility is necessary after installation, an equipment grounding conductor shall be installed.
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Assuming all these raceways are installed per the uses permitted and strapped accordingly then I give you my blessing. If that run is very long and not straight then good luck-- you may need it, esp. if that LFNC is very long. :D
 
Chris 250.118 is there if you are using the metallic conduit as a ground-- I believe.. The EGC that you ran should take care of that. If the flex is more than 6 feet there may be an issue.
 
I agree with Dennis

We see where they rough in with EMT through the roof and then use LFMC to connect to the unit.

I might look at the install pretty close and it doesn't seem very professional to me, but don't see any real violation.
 
cowboyjwc said:
I might look at the install pretty close and it doesn't seem very professional to me, but don't see any real violation.
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I can't fix everything here and this would be a PITA. I know I sited an EGC art with the IMC bonding issue. There is a very off chance the IMC could be energized if the FMC fails during a fault.
 
chris kennedy said:
I can't fix everything here and this would be a PITA. I know I sited an EGC art with the IMC bonding issue. There is a very off chance the IMC could be energized if the FMC fails during a fault.
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Right ,..so are the fittings listed???
 
chris kennedy said:
I can't fix everything here and this would be a PITA. I know I sited an EGC art with the IMC bonding issue. There is a very off chance the IMC could be energized if the FMC fails during a fault.
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yeah, but what if......................?

And don't forget also what if............................?
 
I don't see a problem, assuming the flex is under the 6' that was posted.

MC can have the same issue, if you have a fault inside MC the armor can fail before clearing the fault.
 
M. D. said:
Right ,..so are the fittings listed???
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I'll take a closer look today.

This could be a problem.

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non?current-carrying parts that are to serve as grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them.
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Would FMC under 6' but with an OCPD over 20A fit this requirement?

250.2 Definitions.
Effective Ground-Fault Current Path. An intentionally constructed, low-impedance electrically conductive path designed and intended to carry current under ground-fault conditions from the point of a ground fault on a wiring system to the electrical supply source and that facilitates the operation of the overcurrent protective device or ground-fault detectors on high-impedance grounded systems.
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Also please bear in mind there is a seperate EGC run in this conduit.
 
This is a quote from a Mr. Holt newsletter based on 05


Listed flexible metal conduit. FMC (Article 348) installations must meet four requirements (Figure 250-s118(05) 01 CC250-29.cdr):

The conduit terminates in fittings listed for grounding.
The circuit conductors are protected by overcurrent devices rated 20A or less.
The combined length of the conduit in the same fault return path doesn't exceed 6 ft (Figure 250-s118(05) 02 CC250-30.cdr).
The application requires flexibility.
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In 2008 it has changed a little but I do not think the example you give complies
 
M. D. said:
In 2008 it has changed a little but I do not think the example you give complies
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Yeah, thanks. I can't identify the fittings and its T&M so I'm going to run EMT to the IMC. Cutting the place open.

I do have the inspector coming out tomorrow and will share his take with you.
 
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