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11-06-2007, 06:27 PM #1
The question arrised as to how long Liquidtight could be run. I was thinking 6' was the max but that turned out to be for the flex metal (Article 348.20). Section 350 deals with the Liquide stuff but I could not find a max lenght. Anyone know where I'm not looking? Thanks
11-06-2007, 07:35 PM #2
My semi-SWAG is that you can run any length you like provided you support it correctly and use appropriately sized conductors, including a separate ground pulled in with the active conductors if the length is over 6 ft. The Electrician's Handbook I have says it's "allowed for connections of motors or portable and stationary equipment when flexibility of connection is required." (I'm sure different folks would interpret that different ways.) It also says don't use where subject to physical damage, excessive temperature, or hazardous locaitons. Someone who knows the code may easily prove me all wrong.
11-07-2007, 11:47 AM #3
There is no maximum length specified in the NEC. You do need to properly support the run (within 12" of the ends and at least every 4.5' between). You cannot have more than 360 degrees of bends between pull points (junction boxes or conduit bodies), and you need to run a separate grounding conductor if the conduit will be flexed in use, or if the circuit conductors are rated over 20A.
Long runs of sealtite are generally to be avoided, because the stuff is much more expensive than other wiring methods.
11-07-2007, 08:19 PM #4
cost of it you may want to keep it shorter
I have seen it used over 100 ft. long
11-07-2007, 08:54 PM #5
Thanks for the response, guys. I prefer short runs of the stuff, myself. We happen to have some contractors doing an install and getting a bit carried away with the length -especially since it's outside. I thought fer-sure there would have been a spec.
11-07-2007, 11:47 PM #6
AFAIK, the NEC does not limit the length of LTFMC or LTFNMC ... they do state that LTFMC shall not be used in areas where subject to physical damage per 350.12(1). Also, it shall not be used where any combination of ambient & conductor temperatures produces an operating temp in excess of that for which the material is approved per 350.12(2).
In addition to the high cost of Sealtight, the requirement for support every 4.5', and the requirement for support within 12" of every outlet, means a greater labor cost for the install (versus every 10' for EMT, and within 3' of every outlet).