Good morning!I'm trying to figure out the difference between tray cable types and tray cable ratings. The information I have has the types as, TC, VNTC, PLTC, ITC, XHHW, WTTC. The ratings I have are TC, -ER, WTTC.The questions I have are:1. What is the difference between tray cable types and tray cable ratings? As I understand it, ratings tell you what the cable is approved for and for what applications. Types are the actual specifications of the cables. Is this correct?2. What are the NEC requirements for tray cable to meet type XHHW?

Rating (Listed) = amperage , Type = insulation

"X" = insulation material makeup. "HH" = high heat, 90C
"W" = wet areas. Normally this type of cable can be used in either a wet or dry location.

Ok, I looked up type XHHW cable in NEC 310.104(A) for you.

It is a flame retardant, moisture resistant, thermoset insulated cable. It has temperature listings of 90C in dry or damp locations. In wet locations, the temperature cap is 75C.

Wire type XHHW-2 can be used at 90C in dry, damp or wet locations.

The temperature listings translate to the amperage column to use in Table 310.15(B)(16).

For example 90C, 12 AWG cable, type XHHW is listed at 30 amps max in the 90C column. While in the 75C column its max amperage is 25 amps.


Type XHHW-2 is 30 amps. Regardless of the location.