Bonding Metal Enclosures

[dmulhol925]

Working on a project where we installed a ground ring around the building, from there to the ground buss and metal framing of MCC. From there with a green ground wire to various electrical enclosures ground buss to the metal can.

The engineer says we need to install a panel grounding electrode to the MCC, VFD, PDP tied to site ground.

Is what we did meet the requirements of NEC, article 250?

 

[petersonra]

Working on a project where we installed a ground ring around the building, from there to the ground buss and metal framing of MCC. From there with a green ground wire to various electrical enclosures ground buss to the metal can.

The engineer says we need to install a panel grounding electrode to the MCC, VFD, PDP tied to site ground.

Is what we did meet the requirements of NEC, article 250?

It probably meets NEC requirements. It may not meet your contractual requirements.

 

[david]

Working on a project where we installed a ground ring around the building, from there to the ground buss and metal framing of MCC. From there with a green ground wire to various electrical enclosures ground buss to the metal can.

The engineer says we need to install a panel grounding electrode to the MCC, VFD, PDP tied to site ground.

Is what we did meet the requirements of NEC, article 250?

you need to install a grounding electrode system bonded to the service grounded conductor. I'm not sure that is what you where describing when you say the ground buss to metal framing. You may be describing an equipment ground buss.

assuming this is a grounded system

 

[petersonra]

you need to install a grounding electrode system bonded to the service grounded conductor. I'm not sure that is what you where describing when you say the ground buss to metal framing. You may be describing an equipment ground buss.

assuming this is a grounded system

It seems to me that the ground ring covers the GES requirement.

There is no NEC requirement to bond any of the metal enclosures mentioned directly to the GES.

 

[david]

There is no NEC requirement to bond any of the metal enclosures mentioned directly to the GES.

a grounding electrode system bonded to the service grounded conductor.

Thats not what i said there is a NEC requirement to bond the GEC to the grounded counductor at the service by a main bonding jumper(size 250.66 & 12.5 % of the ungrounded conductor) that is a buss or main bonding jumper that is a wire (strap)

The OP seem to indicate by bonding the ground ring to all the equipment ground buss in the respective panels he mentioned was accomplishing that.

It seems to me that the ground ring covers the GES requirement.

I was careful to say grounding electrode system the OP asked did the ground ring meet the NEC grounding requirements. (metal water sytems, building steel, footer rebar if any)

 

[petersonra]

I am inclined to agree there are a lot of questions raised by what the OP did not bother to include in his post. I tried to answer the question he actually asked though without getting into all the potential side issues.

My guess would be that given there is an engineer involved, there are some things the engineer wants done that are not code required. As far as I am concerned, if they are in the spec, it is a contractual requirement even if not required by code (as long as the code does not prohibit it, of course). The OP likely did not bid to code but to the spec, and that is what he should be installing.