Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,201
I made the mistake of reading this, and now I don’t know which of you is correct.
Breaker Voltage
www.electriciantalk.com
I think the comments laid it out pretty clearly. But commenters aren't authoritative, just as we forum members aren't.
"I've heard them called "slash rated". The lower rating is phase to ground voltage, the higher is phase to phase. As Bird dog said, the issue comes up in wanting to use the high leg on a 3P4W delta for a single phase 208v load; the breaker has to have a phase to ground rating of at least 208v, which a slash rated breaker does not."
"120/240V Slash rated breakers are suitable for 1Φ or 3Φ loadcenters, where the highest voltage to ground is 120V and the max voltage phase to phase is 240V. Also used in 120/208V 3Φ 4W Wye systems.
240V Straight rated breakers are suitable for 1Φ or 3Φ loadcenters, where the highest voltage to ground is 240V and the max voltage phase to phase is 240V. Such as in a Center tapped delta system, where the wild leg is 208V to ground.
Most 3P breakers come standard with a straight 240V rating.
2P units can come either way, normally slash rated, but straight rating is required if your connecting to a 208V wild leg.
BR240H is an example of a 2P unit with a straight rating, for use on a center tapped delta system."