Have 400 amp/1 phase service disconnect outside of building . Inside feeds to automatic transfer switch from generator and to sub panel.this was pre-wired to a 200 sub panel from factory in transfer switch a ground wire was tied into the neutral bar in transfer cabinet. there is a ground bar with equipment grounds. do not think this should be tied into neutral. to me it the same as the sub panel where we do not tie neutral and equipment grounds together.Is this done so breakers can see short circuit current with when in under generator mod?
grounding for automatic transfer switch
- Thread starter lroselle
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petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: grounding for automatic transfer switch
I think it depends on whether or not the transfer switch switches the neutral or not.
I think it depends on whether or not the transfer switch switches the neutral or not.
wirenut1980
Senior Member
- Location
- Plainfield, IN
Re: grounding for automatic transfer switch
To elaborate some more, whether or not the neutral is switched will tell you whether or not you have a separately derived system. see 250-20 in 99 NEC. You will then be referred to 250-30 if it is a separately derived system. If it is not a separately derived system, then I believe the grounded and grounding conductors should be kept separate.
To elaborate some more, whether or not the neutral is switched will tell you whether or not you have a separately derived system. see 250-20 in 99 NEC. You will then be referred to 250-30 if it is a separately derived system. If it is not a separately derived system, then I believe the grounded and grounding conductors should be kept separate.
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