How many?

[mstrmp3]

How many 18AWG THHN class 3 (24vac 50VA) conductors are allowed in a 3/4" PVC?

 

[tkb]

Are you sure it is THHN?
I never saw THHN under #14.
NEC only lists THHN down to #14.

 

[chris kennedy]

NEC only lists THHN down to #14.

Maybe so, yet available, see this.

 

[rbalex]

Maybe so, yet available, see this.

WOW - and only 4mil thick insulation.

 

[hbiss]

...only 4mil thick insulation.

That has to be a mistake, must be the outer nylon covering thickness. That makes me doubt that they have THHN smaller than 14. TFFN looks identical to THHN and can be had in 16 and 18 ga.

Unless this is Chinese junk...

-Hal

 

[nhfire77]

...only 4mil thick insulation.

That has to be a mistake, must be the outer nylon covering thickness. That makes me doubt that they have THHN smaller than 14. TFFN looks identical to THHN and can be had in 16 and 18 ga.

Unless this is Chinese junk...

-Hal

Exactly T310.13(A) THHN is 14 GA is larger with at least 15 mils of insulation.

 

[mstrmp3]

sorry, it's TFF (MTW?) not THHN. But it definately is 18 gauge

 

[augie47]

It is listed in Appendix C For Sch 3/4" 40 PVC 23 #18 TFF
For Sch 80 18 #18 TFF (pg 70-752 in '08)

If you find it in TFFN your numbers increase somewhat (37 in Sch 40)

 

[mstrmp3]

Thanks!

 

[G._S._Ohm]

So if 15 mils is good for 600 VAC then 4 mils may be good for 150 VAC.