2029 PI: 110.14(C) Number 2

[wwhitney]

Change:

110.14(C) (1) Equipment Provisions.
The determination of termination provisions of equipment shall be based on 110.14(C)(1)(a) or 110.14(C)(1)(b). Unless the equipment is listed and marked otherwise, conductor ampacities used in determining equipment termination provisions shall be based on the values from Table 310.16 as appropriately modified by , or Table 310.12 where applicable, without the application of any adjustment or correction factors.

. . .

Substantiation:

The phrase "based on Table 310.16" suggests that all of Table 310.16 applies, including the footnotes calling for ampacity adjustment and correction. It also suggests that the table value may not be the final answer for the ampacity of termination provisions, and that further modification may be necessary, such as applying ampacity adjustment and correction factors.

However, neither of these is true. UL listing standards for equipment incorporate the numbers from Table 310.16 for sizing conductors for equipment testing, without any adjustment or correction factors. And any deviation from that rule is covered by the initial phrase in this sentence of 110.14(C).

Changing the text of 110.14(C) to directly reference the values of Table 310.16 without correction or adjustment will thus increase clarity.

 

[tortuga]

@wwhitney another good one, step in the right direction,
I have always wondered why even reference those two tables and not all the tables as appropriate for the wiring method, there is wiring methods like buss duct, cable buss, cable tray, and free air conductors that may be outdoors on free air terminations that can handle well over 310.14 or .12 table values,
and not to mention for over 600V and up, like 690V systems, the default was 90C terminations until 2017 or so when it moved to 1000V.

 

[wwhitney]

I have always wondered why even reference those two tables and not all the tables as appropriate for the wiring method

I gather that the UL listing standards specify testing with wires sizes based on Table 310.16, and that when other wire sizes may be used, require that the product be so labeled. I have obviously not confirmed this by checking every UL listing standard.

Cheers, Wayne