The safety reason for the change is that bonding enclosures with a cuurent carrying conductor is not a good idea.
Regarding services...if this passes I plan on submitting the same concept for services in 2011. Of course, services don't typically fall under the scope of the NEC, but as written now, you don't have the option of installing an EGC from the transformer and bonding it to the enclosure, and floating the nuetral at the service.
Ryan Jackson, Salt Lake City
Re: Rumors of 2008 changes#154551 01/27/0601:50 PM01/27/0601:50 PM
That certainly sounds like a hard sell. You will need to coordinate this change with the NESC and I bet the utilities who sit on those CMPs will veto it. I do see the value of the idea but I doubt the utilities will. This is the kind of idea that needed to be established back when Edison and Westinghouse were deciding what the grid would look like. It will certainly make me want some stock in Landis & Gyr and Thomas & Betts. They will have an instant market for a couple hundred million meter bases.
Re: Rumors of 2008 changes#154552 01/27/0602:02 PM01/27/0602:02 PM
If the NESC CMPs are anything like the NEC CMPs they are packed with industry reps. If the industry doesn't want something it don't happen. On the other hand, if they have a product they are pimping it gets fast tracked to the front of the line, ready or not. I only have to point to 210.12 and products that were put in the code, in spite of the fact they didn't exist. Personally I think the whole process is broken, bordering on being corrupt.
Re: Rumors of 2008 changes#154554 03/11/0607:22 PM03/11/0607:22 PM
Even I, a non-electrician, can see the safety advantage of not doing things as in 250.32(B)(2). I'd be happy to see that go away.
But as for 210.12(B) being expanded, I'd say we are not really ready for that, yet. We may not be for quite a while. But I do think we could live with it expanding provided that some better exceptions are made available, such as for dedicated circuits. Maybe it could be expanded to some additional areas of the home. Maybe an exception could be made for some areas (where cords are unlikely to be an added safety hazard) when AC, MC, or metallic conduit protects the wiring.
We could end up seeing a lot more AFCI breakers for sale on EBAY as homeowners end up doing their own replacements. What may be more influencial regarding this would be how homeowner insurance policies are written. If existance of AFCI protection is required for lower rates (and undocumented substitution discovered after a fire results in non-payment), then I can see more of this coming about. While I could imagine the insurance industry would back this change, I would think they could effect the change through their rate structures, too.
Re: Rumors of 2008 changes#154555 09/12/0601:55 AM09/12/0601:55 AM
Regarding the expansion of AFCI's...I think the NFPA is setting itself up for a huge blackeye with this one. Considering the fact that the AFCI's must be the combination type, and nobody has a functioning AFCI type available yet, I can't see how the NEC would require a device to be installed throughout the entire house, when we don't even know if it works!