Question: Is there a UL labeling procedure for grounded B phase Service Entrance?? Additionally, I know I am going for the two for one question here, When using a grounded B phase on 480VAC you must be mindful of the fault current going through only one pole and you cannot fuse or put a breaker in the B phase, are there any any other 480VAC Grounded B phase application issues??
480V, 3ph, Grounded B phase Delta Service
- Thread starter sstock
- Start date
- Status
- Location
- Illinois
- Occupation
- retired electrician
The breakers must be fully rated and not "slash" rated as far as the voltage. That is you cannot use a breaker marked 480/277, it must be marked 480. Some single phase panels and disconnects are listed for use with ground phase systems and the use of so listed equipment can bring the costs down.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Yes, UL has listing requirements for corner-grounded systems.
Because of the single pole fault handling you mentioned, the AIC ratings for corner-grounded rated breaker is usually substantially lower than for other systems.
Some manufacturer's have somewhat different construction for corner-grounded systems (i.e. building a 2-pole breaker using a 3-pole wide housing).
Because of the single pole fault handling you mentioned, the AIC ratings for corner-grounded rated breaker is usually substantially lower than for other systems.
Some manufacturer's have somewhat different construction for corner-grounded systems (i.e. building a 2-pole breaker using a 3-pole wide housing).
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