Grounded conducter used as equipment ground?

[ctroyp]

I would like to hear comments about the use of grounded conductors use in place of GEC or an EGC. Specifically, at a meter base 250.142.B Exception No.2.
I personally feel it is best to use a GEC for this duty on a typical residential installation.

[ September 11, 2003, 05:02 PM: Message edited by: ctroyp ]

 

[brian john]

Re: Grounded conducter used as equipment ground?

If I understand you correctly, your asking about utilizing a 4 conductor cable between the meter base and panel?

If this is a standard meter base and the grounded conductor/neutral termination connection is mounted to the back box. Then you are installing parallel conductors, the GEC will be in parallel with the grounded conductor or vicesa versa.

 

[roger]

Re: Grounded conducter used as equipment ground?

The only fault clearing path on a typical service is the POCO Grounded Conductor (Neutral). The GEC (if we are talking rods) serves no purpose in clearing a fault and the EGC is soley dependant on the POCO Grounded Conductor (Neutral)

In otherwords the POCO neutral is the system EGC.

Roger

[ September 11, 2003, 07:23 PM: Message edited by: roger ]

 

[ctroyp]

Re: Grounded conducter used as equipment ground?

Originally posted by brian john:
If I understand you correctly, your asking about utilizing a 4 conductor cable between the meter base and panel?

Not exactly...

I understand from what roger says about the POCO grounded conductor is being used as the EGC for the meter enclosure (back-feeding, if you will.) I am not exactly asking how this is done, but more of some lingering skepticism that 'is this the best way to ground the meter enclosure?'

I'm not the most fluent person with the NEC so bare with me. I am returning back to this type of work after several years of being in industrial automation--I haven't dealt w/services in a while.

Here is a senerio:
200A 240V 1PH residential service.
POCO grounded conductor and terminal (inside meter base) bonded to meter enclosure.
Non-metallic conduit in and out to the 200A panel.
3-wire POCO L1-L2-N to meter...same to panel w/o GEC nor EGC.
#6 GEC from ground rod to panel only--bonding screw installed.
#4 water bond to water pipe.

I'm not suggesting installing a EGC from the panel back to the meter base since that is established from the grounded conductor. But, it just seems more practical to run the GEC (from the ground rod) to the meter base directly, bond the POCO (neutral) and GEC there, instead of running the GEC inside to the panel(if he panel is inside) and leave the water bond as usual as well as the panel bonding screw.

I know I just twisted things up a little but I was just curious to hear what others had to say about this. :roll: