Where the code allows for installing a bonding conductor in mettalic conduit it states that the conduit must be bonded on both ends, question is if this is installed in mettalic conduit , attached to a metal building , does this reduce the requirement for bonding of the conduit?

The bonding of the Grounding Electrode Conductor ( GEC) to each end of a metal raceway is required in 250 Part C, 250-64.

It appears the question has the GEC and the Equipment Grounding Conductor (EGC) inter-mixed.

Where a metal raceway encloses an EGC, I do not know where the NEC requires bonding each end of a metal raceway to the EGC. I also do not know where the NEC prohibits that practice.

250 Parts D, E, F, G, in general covers the equipment grounding required for systems less than 1000 volts.

Glenn

After re-read your question;

Each and every metal raceway enclosing the GEC must be bonded to the GEC at each end.

That would be Troughs, Conduits, Nipples, Junction Boxes, Switch and Meter enclosures etc.

Just by having the GEC metal raceway secured to a metal building structure would not accomplish this.

Glenn
Glenn

Chuck,

Welcome to our Forum.
Others here can give you a more detailed answer I'm sure, but I'll give it a try. If you're talking about the Grounding Electrode Conductor (GEC) it must be bonded to the conduit so that it can work properly in the event of a Fault. If it is not bonded and there is a sudden rise in current flow on the conductor fields may be set up that will oppose the current flow and effectively "choke" it.

Anyone feel free to correct me or add to this.

Bill

Gentlemen, I am talking about a water pipe bond from the service eqipment to the water service as we require locally.

Chuck,

Yes, that is what we are talking about if I understand it correctly. The conductor from the service that is connected to the water pipe runs through a metal conduit. this must be bonded at both ends as described in the code section mentioned. Over at the IAEI forum there was a recent thread with questions regarding types of clamps used and there are some pictures there too. take a look.
http://www.iaei.com/ubb/Forum1/HTML/000019.html

I hope this helps,

Bill