Doing an inspection on a 13.8KV to 480V 3 phase power distribution transformer. Found that equipment grounding conductors ran from grounding buss in distribution panel directly to XO. XO is also bonded to transformer in 2 places and to the grounding electrode. This is a wye secondary. Is this acceptable or in any way dangerous? Also there is no grounded conductor. Thankyou
Transformer Grounding
- Thread starter tpd
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Assuming the transformer is the service supply to the building.
Since the transformer has a grounded XO terminal, 250.24(C) requires that a grounded conductor be run to each service disconnecting means.
If there is no neutral load, that grounded conductor is sized by 250.24(C)(1).
It would need to be terminated at the service disconnect on a buss that is bonded to the service equipment.
In actual install I have seen this termination on a "neutral bar" that is then bonded to the enclosure and I have seen it terminated on a "ground bar" attached to the enclosure.
I think the conductor you are identifying as an "equipment grounding conductor" is in fact the Grounded conductor referred to in 250.24(C)
Since the transformer has a grounded XO terminal, 250.24(C) requires that a grounded conductor be run to each service disconnecting means.
If there is no neutral load, that grounded conductor is sized by 250.24(C)(1).
It would need to be terminated at the service disconnect on a buss that is bonded to the service equipment.
In actual install I have seen this termination on a "neutral bar" that is then bonded to the enclosure and I have seen it terminated on a "ground bar" attached to the enclosure.
I think the conductor you are identifying as an "equipment grounding conductor" is in fact the Grounded conductor referred to in 250.24(C)
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