3 wire vs 4 wire ATS with no GFI Concern
3 wire vs 4 wire ATS with no GFI Concern
(OP)
I have 2 non-utility transformers (480-415/240) that are solidly grounded in 2 different buildings.
Building A has a single aforementioned transformer
Building B has the second aforementioned transformer and an ATS and the load
I want to feed the 3phase 4 wire load with the transformer through the ATS, Obviously.
There are no GFI concerns
Do I need a 4 pole ATS?
Looking for code or IEEE info
Building A has a single aforementioned transformer
Building B has the second aforementioned transformer and an ATS and the load
I want to feed the 3phase 4 wire load with the transformer through the ATS, Obviously.
There are no GFI concerns
Do I need a 4 pole ATS?
Looking for code or IEEE info
This is your life and its ending one moment at a time.
RE: 3 wire vs 4 wire ATS with no GFI Concern
" I have 2 non-utility transformers (480-415/240) that are solidly grounded in 2 different buildings.....I want to feed the 3phase 4 wire load with the transformer through the ATS, #1. Obviously. There are no GFI concerns.... #2. Do I need a 4 pole ATS?... #3. Looking for code or IEEE info".
#1. It is essential to treat the N1 and N2 separately in order to prevent circulating current. However, the G1 and G2 can be connected together if feasible. Threat each transformer as an independent four wire + G power source.
#2. Use a 4-pole ATS to avoid neutral circulating current, including simplifies individual ground fault protection. There are schemes showing use of three-pole ATS with alternatives ground fault protection etc. Please avoid it. There are 4-pole ATS available at very little additional cost.
#3. In US NEC is the Law. Comply it. Any mention in IEEE are "recommendations ", as a good reference.
Che Kuan Yau (Singapore)
RE: 3 wire vs 4 wire ATS with no GFI Concern