When using a cable tray to lay a single-core cable, inquire about the allowable current

[plasticlove]

Hello, I am a Korean participating in electrical construction work in the United States. I am planning to install power cables in a cable tray, but I do not understand exactly which NEC regulations to apply.

I am planning to install a 500kcmil, 90°C rated, single-core copper cable on a cable tray. In this case, I am wondering whether I should apply Table 310.15(B)(17) or Table 310.15(B)(16)

Table 310.15(B)(17) shows the allowable ampacity for cables installed in free air, but it does not mention anything about cable tray installations. When I ask AI, it suggests referring to Table 310.15(B)(16). However, I understand that Table 310.15(B)(16) applies to the allowable ampacity for multiconductor cables.

I would appreciate it if you could clarify whether Table 310.15(B)(16) indicates the allowable ampacity for multiconductor cables as well as for single-conductor cables in steel conduits, cable trays, and cable ducts, or if it only applies to the allowable ampacity for multiconductor cables

 

[ron]

There are applicable tables in Article 392 for cabletray that will affect whether you can sue the standard ampacities in 310.15(B)(16) or the free air ratings of 310.15(B)(17).

I typically use the tables in 392 to use the amapcities in 310.15(B)(16) for simplicity.

 

[ramsy]

tables in 392 to use the amapcities in 310.15(B)(16)

Looks like free air tables are prohibited.

(1) Where conductors are installed in cable trays, the provisions of 392.80 shall apply.