# Grounding and bonding of A delta wye transformer



## Awg-Dawg (Jan 23, 2007)

markbrady said:


> I am wiring a 3 phase delta wye transformer that has a copper bonding strap installed from the manufacturer.


 Theres a good chance that's not a bonding strap to the XO


markbrady said:


> Question, is this correct or should i have terminated the primary, secondary grounds AND the bonding wire i brought to building steel under the same lug and brought a jumper from said lug and connected that to the X0?


 I usually put a 3 lug on XO.

Neutral,GEC and jumper to frame.

On frame I put 3 lug.

Jumper to XO, incoming EGC and outgoing EGC.


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## markbrady (Jun 2, 2014)

*thanks*

I used to do something similar but after going over 250-30 i changed it up. 250-30(A) states that a separately derived system shall except as otherwise permitted in this article, a grounded conductor shall NOT be connected to normally non-current carrying metal parts of equipment, be connected to EGC's, or be be reconnected to ground on the load side of the system bonding jumper. 
So I am unsure if I am understanding it wrong or if changing it from the way I used to is making me question myself because I used to connect a jumper from Xo to the EGC's but this is saying not to which is new language in the 2011 code.


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## Awg-Dawg (Jan 23, 2007)

markbrady said:


> I used to do something similar but after going over 250-30 i changed it up. 250-30(A) states that a separately derived system shall except as otherwise permitted in this article, a grounded conductor shall NOT be connected to normally non-current carrying metal parts of equipment, be connected to EGC's, or be be reconnected to ground on the load side of the system bonding jumper.
> So I am unsure if I am understanding it wrong or if changing it from the way I used to is making me question myself because I used to connect a jumper from Xo to the EGC's but this is saying not to which is new language in the 2011 code.


 The system bonding jumper is in your XFMR.

You aren't reconnecting after the jumper.


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