Roof liquid tight conduit

[hhsting]

I have condensing unit on rooftop with disconnect 6 feet away. The conduit used is liquid tight conduit.
Can this type of conduit be used in roof? I looked at 356 NEC 2017 but I am not clear

 

[infinity]

The only issue would be if it were subject to physical damage. There's probably a million feet of this stuff installed on roofs all over this country and is a standard installation practice in the manner that you're described.

 

[augie47]

It can be but there a couple of pitfalls to watch for in addition to p[physical damage::
Art 356 Notes: "(3) For outdoor locations where listed and marked as suitable for the purpose" but most LFNC I've seen is so listed/marked
You also need to note the listing restrictions::
Conduit marked ‘‘___C dry, 60 C wet, 60 C oil res’’ (or ‘‘___C dry, 60 C wet, 60 C oil resistant’’) is for use at a temperature of 105°C (221°F) and lower temperatures in air, and at 60°C (140°F) and lower temperatures where exposed to water, oil or coolants, with ‘‘80,’’ ‘‘90’’ or ‘‘105’’ inserted as the dry-locations temperature
I may be mistaken but it is my understanding that due to that listing you would need to size the conductors based on their 60°ampacity.

 

[don_resqcapt19]

...
I may be mistaken but it is my understanding that due to that listing you would need to size the conductors based on their 60°ampacity.

That is correct, the actually running current must not exceed the 60°C ampacity of the conductors where the conductors are installed in LFMC or LFNC located in wet locations.

Note that I use the running current or full load current, and not the Minimum Circuit Ampacity current for this application. The MCA is a fictitious code generated current and not an actual load current. Not everyone agrees with that.