Use of Grounded Conductor for equipment grounding

[timbates88]

lOK I have this situation where a contractor has installed our distribution xformer (customer owned so i consider an SDS) 13200 to 480/277 and they terminated it to a 3 phase 3 wire MCC with main. My issue is they landed on XO in tranny and other end they terminated to EGC busbar so in my Email im preparing they violated 200.2(B) and was recommending to make the XO terms a SSBJ and put a SBJ in and problem solved but in my continued reading I noticed 250.142 the use of grounded conductor for equipment grounding and 250.142 (A)(1) (A)(2) and I cant quite grasp the wording therein surely that cant be correct wouldnt that make fault current on all metal parts if so? And BTW i have been reading the forum for years and respect the advice of yall
HELP

 

[augie47]

O a SDS you have a System Bonding Jumper just as you have a Main Bonding Jumper fro a service where you have a Neutral to Grounding connection. This is necessary to provide to provide Effective Ground Fault Current Path. You are correct in that that
SBJ cnqa be at the transformer or panel but a SSBJ is still required.
250.142 wording is necessary to see that this path is established when Grounded-Grounding connections are normally not allowed.

 

[timbates88]

O a SDS you have a System Bonding Jumper just as you have a Main Bonding Jumper fro a service where you have a Neutral to Grounding connection. This is necessary to provide to provide Effective Ground Fault Current Path. You are correct in that that
SBJ cnqa be at the transformer or panel but a SSBJ is still required.
250.142 wording is necessary to see that this path is established when Grounded-Grounding connections are normally not allowed.

I guess i didnt word it correctly i was proposing the wires currently there ine end on XO and other end on EGC busbar be taken off of the XO and make them the SSBJ since yhe mcc end is already lnded on egc busbar therefore only needing the sbj for effective path i dont see where the grounded conductor has to be brought to disconnecting means which would be impossibe beingvtheres no spot for it but if they were to leave as is can they quote 250.142 on me?

 

[david]

see outside source 250.30 (C)

 

[don_resqcapt19]

I don't see any issues with the install as long as there is a connection to a grounding electrode somewhere.