Conduits and Bushings 300-4(f)

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muhandas

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I have the following situation. 600 mcm main service conductors run from the utility transformer to 3 main distribution panels through 4? rigid nonmetallic conduits. The problem is that where the conductors exit the conduits there is no bushing installed. Of course, this is in violation of 300-4(f) which requires such bushings. However, the installation is nearly complete and it would require significant effort to rectify. Inasmuch as the conductors appear unharmed (I plan to check insulation integrity with a Megger), would a ?retrofit? using a split bushing, not necessarily Listed for the purpose, or perhaps even a wide ?Ty-wrap? around the conductors where they emerge from the conduit, be acceptable to keep the conductors away from the edges of the conduit, and still be deemed to be in compliance of the NEC?
Given the size of the conductors, the installation is pretty rigid and they will not move to be abraded by the conduit?s edge.
Any other suggestions?
Appreciate your help.
Thanx.
Heinz R.
 
Re: Conduits and Bushings 300-4(f)

A bushing is a bushing. #4 or larger conductors in the conduit and it's required. Cutting one and putting it on is a technical violation since it wasn't listed to be cut and installed. Having said that, it's done all of the time.
 
Re: Conduits and Bushings 300-4(f)

Originally posted by paul:
I know I've seen insulated throat liners up to 4" before, but I cannot find them. Arlington Industries makes them up to 2".
Click to expand...
The requirement is for a fitting. I don't know if a throat liner would qualify as a fitting. It can be a "substantial insulating material" but that must be fastened in place to satisfy 300.4(F).
 
Re: Conduits and Bushings 300-4(f)

(F) Insulated Fittings. Where raceways containing ungrounded conductors 4AWG or larger enter a cabinet, box enclosure, or raceway, the conductors shall be protected by a substantial fitting providing a smoothly rounded insutlating surace, unless the conductors are separated from the fitting or raceway by substantial insulating material that is securely fastened in place.
 
Re: Conduits and Bushings 300-4(f)

Paul, I looked at your link. It seems that the Arlington liners would be compliant if they are able to be fastened in place. We've never used them but they seem like they might be fastenable from the photo. Too bad they don't come in 4". I think that Heinz may be out of luck.
 
Re: Conduits and Bushings 300-4(f)

Thanks to all. I appreciate your help and informed comments.
Heinz R.
 
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