richwaskowitz
Senior Member
- Location
- Shelby Twp. MI, near Detroit
I need to understand why a 2 or even a 3 kVA control transformer needs a #8 copper bonding jumper when the phase conductors only need to be sized for the FLA. UL508A 16.2 sites table 75.1 which is identical to table 250.66 in the NEC. They both require a minimum of #8. Why so big for a transformer with a secondary FLA of only 16.6 amps? 16.2 has an exception for a 1 kVA or less, but not for 2 or 3 kVA.