yesterlectric
Senior Member
- Location
- PA
- Occupation
- Electrician
When is it okay when adding components to relay racks, switchgear, large switchboards, or similar equipment, to use the more readily available THWN-2 to run between components in the equipment instead of needing to use the SIS wire that usually ships fro the factory?
Per 300.3A, conductors in table 300.4A (including THWN-2 and SIS) should only be installed in a chapter 3 raceway. However 300.2B clarifies that article 300 is not intended to regulate internal wiring of equipment (no mention of if that exclusion is for field wiring or only factory wiring).
I'm wondering if this is a UL product standard (there goes $5,000 more in book fees) thing instead of an NEC thing?
"Talk to the manufacturer and follow their instructions" may be a response, but they likely won't answer and it's likely a generic requirement applying to a lot of applications.
Per 300.3A, conductors in table 300.4A (including THWN-2 and SIS) should only be installed in a chapter 3 raceway. However 300.2B clarifies that article 300 is not intended to regulate internal wiring of equipment (no mention of if that exclusion is for field wiring or only factory wiring).
I'm wondering if this is a UL product standard (there goes $5,000 more in book fees) thing instead of an NEC thing?
"Talk to the manufacturer and follow their instructions" may be a response, but they likely won't answer and it's likely a generic requirement applying to a lot of applications.