Parallel Path to ground, Corner bonded delta

[Tbatson44]

I am new to work on installing transformers. I've listened to Mike Holt's stuff and tried to pay close attention, although much is still over my head. My question is on the grounding video. He goes through parallel paths to ground. I am looking at a diagram for corner bonded delta. Phase C in this case is gray wire going into the plant and same with the EGC. Can someone explain in easy terms why this isn't parallel paths? Thank you.

 

[infinity]

Is this video on the internet, if so do you have a link to it?

 

[Strathead]

I am new to work on installing transformers. I've listened to Mike Holt's stuff and tried to pay close attention, although much is still over my head. My question is on the grounding video. He goes through parallel paths to ground. I am looking at a diagram for corner bonded delta. Phase C in this case is gray wire going into the plant and same with the EGC. Can someone explain in easy terms why this isn't parallel paths? Thank you.

Are the EGC and the gray wire joined together in the panel and in the transformer? In my opinion they should only be joined together in one location.

 

[don_resqcapt19]

I am new to work on installing transformers. I've listened to Mike Holt's stuff and tried to pay close attention, although much is still over my head. My question is on the grounding video. He goes through parallel paths to ground. I am looking at a diagram for corner bonded delta. Phase C in this case is gray wire going into the plant and same with the EGC. Can someone explain in easy terms why this isn't parallel paths? Thank you.

The connections for the corner grounded system should really be the same as with a 120/240 single phase system. With both systems, if there is only one point of connection to the grounding conductors from the grounded conductor, there is no parallel path.

 

[kwired]

I am new to work on installing transformers. I've listened to Mike Holt's stuff and tried to pay close attention, although much is still over my head. My question is on the grounding video. He goes through parallel paths to ground. I am looking at a diagram for corner bonded delta. Phase C in this case is gray wire going into the plant and same with the EGC. Can someone explain in easy terms why this isn't parallel paths? Thank you.

More details please. Is the transformer utility transformer supplying the "service" or is it plant owned and a "separately derived system?

If a service supply, there is no need for more than one grounded conductor, but beyond service equipment the rules are same as for systems with grounded neutral conductor - grounded (current carrying) and equipment grounding conductors are separated.

If a separately derived system are you bonded at the transformer or at the first disconnect, should be one or the other but not both. A separate SSBJ still needs run between those two points either way, it can be metal raceway.

 

[Tbatson44]

Sorry I didn't reply, I thought I would get an email with reply. It is not separately derived. Really the concept makes sense, I couldn't wrap my head around them being connected together, but it is only at that one point. The concept makes sense being the same as as others. Thank you. I was just looking for a little more to understand and this is good.