I looked at a building today with a 3 phase corner grounded delta the service disconnect in the building 240 v all three wires were fused with no place for equipment ground can i run a wire from b phase on the line side of the fuse to a grounding buss in the disconnect for equipment grounds. ( should the b phase be fused at the service disconnect) also can i use two pole breakers to run three phase motors if i ground b phase. can i use a single breaker panel .
corner grounded delta
- Thread starter domnic
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- Location
- Massachusetts
How do you know it is corner grounded delta?
Could it be ungrounded delta?
If it is corner grounded delta the fuse has to go, 240.22 and the grounded conductor has to be white 200.6 (Remember that Article is grounded conductors, not 'neutral' conductors)
It has been pointed out before that some single phase equipment is OK to use with corner grounded delta.
Could it be ungrounded delta?
If it is corner grounded delta the fuse has to go, 240.22 and the grounded conductor has to be white 200.6 (Remember that Article is grounded conductors, not 'neutral' conductors)
It has been pointed out before that some single phase equipment is OK to use with corner grounded delta.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
domnic said:
Yes, you have a grounded phase system.
It is possible to use two pole breakers. However any circuit breaker, and panel, you use must be labeled for this system. You will not be able to use standard 120/240V 2-pole breakers. Pay attention to your available fault currents.
The existing fuse, in the grounded conductor, must be removed as Bob mentioned.
You may treat your grounded and grounding conductors the same as you would in any other installation
- Location
- Illinois
- Occupation
- retired electrician
Yes, those voltages show that you have a grounded system, but is it an intentionally grounded system?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
don_resqcapt19 said:
Very good point.
- Location
- Massachusetts
don_resqcapt19 said:
That was what I was wondering from the outset. :smile:
The fact there are 3 fuses was to me a possible hint that it was supposed to be a ungrounded system.
zog
Senior Member
- Location
- Charlotte, NC
Are there ground detector lights?
- Location
- Massachusetts
zog said:
Is the 'grounded' phase marked white?
So many questions.
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