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#82804 - 12/14/02 01:08 PM Residential Wiring Questions  
Joe Tedesco  Offline
Joined: Oct 2000
Posts: 2,749
Boston, Massachusetts USA

I am a regular subscriber for this ECM for a long and really enjoy this mag. with my trade. I am working in Design/ Construction Division, and inspecting my projects. Those are mainly concern with residential wiring, service equipment, and dealing with utility company.

On my project, the contractor install all apts. branch wiring in the newly constructed open ceiling and wall. Also, there is and other systems involved like sewage pipe, sprinkler pipe, heating & plumbing pipe and gas pipe.

Now, as far as I seen the AC-90 armored cable installed for branch wiring and apts risers are all physically touching, overlapping, and intercepting other house system throughout the bldg. For my curiosity, I measure the potential between the live (110 V) and the sewage pipe (Cast Iron ). and the reading shows 50v. So does the other metal piping system gave me different reading. It is basically grounded the other system by physical contact of all BX-cable in the bldg.

Now, my question is....

Is it advisable to keep this method of wiring as a safer practice?
If in case of an accident, like the broken neutral or missing grounding system, it is proven to be a very dangerous and fatal, so how do I support my objection and comments against the GC Contractors?

I constantly address this issue and wanted to be corrected, but there is no supported documents like in the specification or the NYC Electrical Code Standard specifically this situation.

Is this condition is a code violation?

Appreciate your prompt detail reply at your earliest....

Raj Patel 12/14/02

Note: I did come across the article of a GFCI Receptacle made in China a couple of months ago. And those are the recalled for some technical reason. NEC advised in that article not to use them.
Some how I lost the article, and not even sure that those are all the GFI made in China including UL listed or not.
please, help on this note and appreciate if sending a details to me on my address or e-mail

address: Ranjit Patel
23 Stagg Street
Jersey City, NJ 07306


Thank You.

Raj Patel

Joe Tedesco, NEC Consultant

2017 / 2014 NEC & Related Books and Study Guides

#82805 - 12/14/02 04:51 PM Re: Residential Wiring Questions  
sparky  Offline
Joined: Oct 2000
Posts: 5,311
ideally one would get reading of 110V from 'Hot' to any other mettalic system

#82806 - 12/14/02 10:05 PM Re: Residential Wiring Questions  
ThinkGood  Offline
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI
Sparky, et al:

I know that the cold water has to be connected to the earth ground, per the NEC. Just to clarify, per NEC, must the gas line as well? (That's how my service was installed, and it sure makes sense considering that our range has an electric ignition...)

Hmmm...the drain/waste/vent system. A lot of that is PVC now, or PVC connected to old cast-iron, etc. Not to mention the fact that there are separate "sanitary sewer" and "storm sewer" lines exiting the house.

Are DWV lines addressed by the NEC?

#82807 - 12/15/02 07:39 AM Re: Residential Wiring Questions  
sparky  Offline
Joined: Oct 2000
Posts: 5,311
section V of art 250 addresses 'bonding' , some codes that come to mind per the original post:

250.104(A)(2) Buildings of Multiple Occupancy. In buildings of multiple occupancy where the metal water piping system(s) installed in or attached to a building or structure for the individual occupancies is metallically isolated from all other occupancies by use of nonmetallic water piping, the metal water piping system(s) for each occupancy shall be permitted to be bonded to the equipment grounding terminal of the panelboard or switchboard enclosure (other than service equipment) supplying that occupancy. The bonding jumper shall be sized in accordance with Table 250.122.


The intent of 250.104(A)(2) is to recognize that the increased use of nonmetallic water piping mains causes the interior metal piping system of a multiple-occupancy building to be isolated from ground. Therefore, the water pipe is permitted to be bonded to the panelboard that serves only that particular occupancy. The bonding jumper, in this case, is permitted to be sized according to Table 250.122, based on the size of the main overcurrent device supplying the occupancy.

250.104(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that may become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with 250.122 using the rating of the circuit that may energize the piping system(s). The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible.
FPN:Bonding all piping and metal air ducts within the premises will provide additional safety.


Section 250.104(B) was revised for the 2002 Code to state that gas piping is treated exactly the same as all "other metal piping" systems within a building

#82808 - 12/15/02 07:58 PM Re: Residential Wiring Questions  
harold endean  Offline
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
Technically all metal piping in a house is supposed to be bonded together to form one big grid. This way there will be no stray voltage running around. However here in NJ, the gas company does NOT WANT us to bond to the gas piping. The state feels that there are several connections amongest the gas appliances to have enough bonding through the regular wiring. For example the ground wire on a plug of a gas dryer, or the plug of a gas stove, furnace, boiler, etc. The state feels that there are enough connections between the gas piping and the grounded conductor.


#82809 - 12/15/02 11:17 PM Re: Residential Wiring Questions  
Electricmanscott  Offline
Joined: Jan 2002
Posts: 1,457
Holden, MA USA
Harold, what you describe regarding bonding through appliances and such is exactly what the NEC requires for bonding gas piping.

#82810 - 12/16/02 10:38 PM Re: Residential Wiring Questions  
harold endean  Offline
Joined: Feb 2002
Posts: 2,233
Boonton, NJ

My state flip flops back and forth from grounding the gas pipe, and then not grounding it. It lasted for a year or two. Right now the state accepts the appliance grounding.


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