430.72 vs 450.3

[Isaiah]

I’ve got a 480V (motor) schematic showing a 80VA CPT, @ 480VAC/24VAC.
430.72(B)(4) says I can protect the primary with a 500 percent fuse. And secondary protection is not required per 430.72(B)(3). But 430.72(B)(2) states 450.3 “shall be permitted” for protection...so which one is it?


Sent from my iPhone using Tapatalk

 

[augie47]

IMO, 430.72 would be used.. the "shall be permitted" would not make Art 450 mandatory.
(Note in the '17 Code the "no secondary" allowance is for 50va rating)
also if it is Class 2 wiring, 450.1 exception 3 exempts class 2 and 3 wiring.

 

[Isaiah]

IMO, 430.72 would be used.. the "shall be permitted" would not make Art 450 mandatory.
(Note in the '17 Code the "no secondary" allowance is for 50va rating)
also if it is Class 2 wiring, 450.1 exception 3 exempts class 2 and 3 wiring.

Great feedback


Sent from my iPhone using Tapatalk