Is There a 6 Foot Limit on Flex Between a Disconnect and Equipment?
A user asked the app whether more than 6 feet of flex can be used outside between a disconnect and an air compressor. Good news: the NEC does not impose a general 6 foot length limit on flexible conduit. You can run more than 6 feet of liquidtight between the disconnect and the compressor, provided you follow the support, grounding, and wet location rules that actually govern the install. The 6 foot number people remember comes from narrower contexts, and it is worth untangling them.
Where the 6 foot ideas come from
Article 350 permits unlimited lengths of liquidtight flexible metal conduit as a wiring method. The famous 6 foot figure appears in two other places. First, 350.30(A) has an exception allowing flex to be unsupported up to 6 feet from the last point of securement where flexibility is necessary at equipment. Second, using the metal flex itself as the equipment grounding conductor is limited by 250.118 to 6 foot total lengths in the ground return path, and only for small trade sizes on circuits of limited ampacity. Neither says the raceway cannot be longer; they say longer runs need straps and a wire type ground.
Doing a longer outdoor run right
For an outdoor compressor, use liquidtight flexible metal or nonmetallic conduit listed for wet locations with listed liquidtight fittings, per 350.10 and 356.10. Support LFMC every 4.5 feet and within 12 inches of each termination per 350.30(A), leaving the final flexible section at the compressor unsupported within the 6 foot allowance so vibration does not transfer. Pull wet rated conductors, THWN-2 or XHHW-2, since the interior of any raceway in a wet location is itself a wet location per 300.9. Include a wire type equipment grounding conductor sized from 250.122 on any run beyond the 250.118 limits, which for a run over 6 feet means always.
The motor circuit details
The disconnect itself must be within sight of the motor per 430.102(B), meaning visible and within 50 feet, so verify the compressor location keeps the disconnect in that window. Size conductors at 125 percent of the motor full load current from Table 430.248 or 430.250, and remember many compressors want a dedicated motor rated switch or breaker per 430.109. A longer flex run changes none of that; it just adds straps.