ECN Forum Forums Code Related Discussion NEC & other Code issues Service raceway, or not?

Glenn,
The intent is not to bond the enclosures together with the nipple. This is on the line side of the service disconnect, so both enclosures are bonded to the grounded conductor. The purpose of the bonding the nipple or raceway is to provide a good fault path in the event of a ground fault within the nipple. This bonding requirement is more stringent here on the line side of the service OCPD because the only protective device that could clear a fault at this location is on the line side of the utility transformer.
Don(resqcapt19)

Don,

Not sure which Glenn you are mentioning.

On my post, I mentioned " Only one end of the metal "Service" raceway needs to be so bonded".

I did slip-up on the complete info about the set-screw locknut. A set-screw locknut is not allowed when concentric/eccentric KO's are envolved.

On enclosures for Service conductors, see 250-80.

Only 250-64(e) for a metal enclosure for a GEC needs to be bonded to the GEC at each end and to each enclosure the GEC is in.

Glenn

Guys,
The answer has be bandied around quite a bit here. Let's not forget that it is a service raceway, it is obviously metallic, therefore has a possibility of carrying the entire fault of what must be condidered "unlimited" buss, the fault of the entire outside conductors and network. That is the reason service conduits must have bond bushings installed at EACH end, KO's have nothing to do with it. If your AHJ won't allow bond bushings on each end, please change to PVC asap, not a bad idea altogether.

My inquiry is solely directed at the nipple, and only where concentric rings remain. The meter socket is factory bonded, so the bonding bushing, which I install only on the disconnect side is to bond the nipple to the service disconnect which we are required to bond. My observation has been that the bonding of this short section of service raceway has been ignored. Similarly, in off-peak systems where 2 meter sockets are nippled together, I rarely see the nipple bonded.
BTW,
PECO doesn't want any bonding wires in their sockets either. This poses a problem when entering into the side of the socket with remaining rings.

George,
Please cite the code section that requires each end of the service raceway to be bonded. Thanks.
Don(resqcapt19)

You're right Don, I should have posted an entire answer, sometimes when I throw my 2 cents in, I am merely responding to the question, sorry, I do that in real life too !!!!

The first problem here is 250-92. This requires that ALL non-metallic service parts be bonded together - period. If the utility with the meter in question is not allowing a ground tail to the equipment, they are in violation of the NEC. My copy of the NESC is at work, but I will look when I go in. That is 250-92 (a)(2)

250-94 gives us several problems in this configuration. It gives us several methods of bonding, but only (4) applies to this question. "Other approved devices, such as bonding-type locknuts or bushings " The paragraph below states that "Standard locknuts or bushings shall not be the sole means for the bonding required by this section." Notice that it does not say, if you use a bond bushing on one end, locknuts are OK on the other end. It plainly states that locknuts are NOT acceptable as the bonding means. I have thought for 29 years that was plain enough.

I can see, however, if you are used to smaller services like this one, that it may seem excessive, but you are leaving a HUGE weak spot in your bond to unfused conductors if you fail to use a bond bushing. Check out Soares, now available from the IAEI for entire details, too lengthy to go into in this venue.

OK ??? Friends ????

Once again, all this mess is a strong argument for PVC...

I've switched!

It appears bonding is required at one end. Source: 1999 NEC Handbook, Fig. 250.72
http://www.geocities.com/cinkerf/dwg.jpg

George,
I still don't see anything that requires both ends of a metallic service raceway to be bonded. On the line side of the service disconnect the grounded conductor is used to bond the service equipment, the equipment is not bonded by the service raceways. I always thought that bonding both ends was a code requirement because that is what our local utility requires, but I debated this with Phil Simmons (CMP5 chairman) and lost. The code only requires one end of a metallic service raceway to be bonded. If you want to bond both ends, that is fine, but the NEC does not require it.
Don(resqcapt19)

George,
A follow up question. How do you bond both ends of a service mast for an oeverhead service?
Don(resqcapt19)