TFFN

[paulengr]

As far as I know, THHN, THWN, TFFN, MTW, AWM and so on are all _different_ standards. Meeting one standard does not imply meeting another standard.

While I don't think anyone sells THHN wire that isn't also THWN-2, and so as a practical matter 'all' THHN wire is THWN-2, I don't believe that THHN wire _must_ also be THWN, so somewhere you may be able to get THHN that doesn't also have a wet rating.

-Jon

THHN and THWN used to be distinctly different. You had to pick based on whether or not it was a wet location and in wet locations you might have to suffer with 60 C temperature rise ratings. It has been improved over the years so that what you see now is usually triple rated THHN-2/THWN-2/RHW. And it often has MTW thrown in for good measure, and they are 90 C rise across the board. THHN and THWN are UL 83.

MTW is generally different from THHN. It has a higher strand count (fine strand) which makes it more flexible and more vibration resistant. It also pulls easier. It only requires a PVC jacket (no nylon). That’s not to say that it can’t have a nylon over jacket and be dual rated with THHN. The really upgraded version is TEW which uses tinned conductors. Both are UL 1063.

DLO is I think NEMA. It is often dual rated RHW.

AWM means appliance wiring media. Not necessarily “appliances”. AWM is sort of a pass through. It means that the wire is application specific and a Listed component. UL approves the assembly. For instance electric motor lead wire is AWM.

 

[infinity]

While I don't think anyone sells THHN wire that isn't also THWN-2, and so as a practical matter 'all' THHN wire is THWN-2, I don't believe that THHN wire _must_ also be THWN, so somewhere you may be able to get THHN that doesn't also have a wet rating.

-Jon

I thought so too but we just received these boxes of wire last month.

 

[LarryFine]

I thought so too but we just received these boxes of wire last month.

It does list THWN in the fine print.

 

[hbiss]

From the Gilbarco instructions (Wayne the other main player says the same thing). The Gilbarco 2-wire is the communication circuit.

I see where they do call for a separate conduit for the wiring to the speakers and call buttons because it's NEC class 2.

-Hal

 

[oldsparky52]

I see where they do call for a separate conduit for the wiring to the speakers and call buttons because it's NEC class 2.

-Hal

Reading this post I realize that I'm probably using poor choice of wording when I call the data transfer wires a "communication" circuit. The speaker wiring is a communication circuit and when an electrician hears "communication" they 1st mentally go to something other than a class 1 data transfer circuit.

 

[infinity]

It does list THWN in the fine print.

Yes but not THWN-2.

 

[Eddie702]

Seems I remember that THHN and THWN were different wire in the old days and the dual rating came later. Either I am foggy or someone else will comment

 

[kwired]

From what I have seen for gas stations is they typically have both power conductors as well as signal/control conductors in same raceway, the signal/controls are 725 class 1 circuits and can go in same raceway with the power conductors they are associated with. Older units maybe had multiple control conductors, most newer ones just have two conductors. I think the older ones needed multiple conductors because they were using analog signal (pulsers for metering), these generally were units with mechanical readout on the dispenser. Newer ones are all digital and only need one pair for sending these signals

If the dispenser has credit card reader, sound, video, etc. those are in a separate conduit and are usually art 800 application type cables/conductors.

 

[oldsparky52]

From what I have seen for gas stations is they typically have both power conductors as well as signal/control conductors in same raceway, the signal/controls are 725 class 1 circuits and can go in same raceway with the power conductors they are associated with. Older units maybe had multiple control conductors, most newer ones just have two conductors. I think the older ones needed multiple conductors because they were using analog signal (pulsers for metering), these generally were units with mechanical readout on the dispenser. Newer ones are all digital and only need one pair for sending these signals

That fits my experience.

If the dispenser has credit card reader, sound, video, etc. those are in a separate conduit and are usually art 800 application type cables/conductors.

The card reader data circuit can be run in with the power and data circuit for the dispenser. Video and intercom are separate conduits as well as the intrinsically safe sump sensor circuits.

I've seen drawing calling for a power/dispenser data conduit, a video conduit, an intercom conduit, a sump sensor conduit and a spare. Installing 5 dedicated conduits to 10+ dispenser is ... a job.