# Question about derating -3/4" liquid tight conduit - Three 12 UF-B cables - less than 2 foot distance

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#### Curiousv

##### Member
if conduit distance(liquid tight) is less than 2 feet long - Can we run three 12-2 UF-B cable in 3/4" conduit without worrying about derating?

if I look under non metallic liquid conduit chart - I under 60% but why 2 wire is 31% and one wire is 53%
how can 2 wire be less than 1 wire?

if 3/4" is not big enough 1" will be?

I know UF-B does not need a conduit but this is an external wall - and UB-B cable will terminate inside 200A Eaton BR panel

Also, when three cables - so total 6 current carrying conductors or just 3 ( I mean neural count as current carrying?)

These are 2 kitchen receptacle circuits and1 dishwasher circuit. @Afjes @wwhitney @WorthFlorida

Last edited:

#### wwhitney

##### Well-Known Member
- There is no reason to put 12/2 UF-B in LFNC. If the 200A panel is interior, or if it's on the exterior face of the siding and you enter the panel from the back, then you can use regular NM. If do use a sleeve of LFNC for a cable method, then the issue of securing the cable to the panel enclosure as required is a bit tricky.

- Conduits 24" in length or shorter are exempt from derating. In a 2-wire circuit, both conductors are current carrying.

- The fill ratio for 2 conductors is smaller because the two conductors can jamb side by side.

- If you actually did pull 3 flat cables inside a conduit (almost never a good choice), for each flat cable you'd need to take the largest dimension and treat the cable area as the circle of that diameter. Then check your fill ratio.

Cheers, Wayne

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