most of my new home electrical installations i install a meter/breaker combo and run a 4 wire to the main panel. on a current job i was able to run a nearly back to back installation. (nearly meaning the meter was 3' lower than the panel)i installed meter base only and ran a 3wire to the panel. my question is..if i run the grounding electrode conductor from the rod into the meter base and then on into the panel will this constitute a parallel path for the neutral? please cite any code ref's. thx, ken m
tom, thx for your reply. so the best or proper method would be to run the gec from the rod through the meter can (with no termination) ending and terminating on the grounded bus in the main panel? thx, ken m
Re: parallel neutral#82681 12/08/0211:32 AM12/08/0211:32 AM
In northern NJ where I inspect. the power company doesn't want the GEC inside of their meter enclousre, nor do they reay want any other wire in there or passing through it. Check sec. 250-24(a)(1) 1999 NEC where it say..."any assessible point...". The service meter technically is not assessible.
Re: parallel neutral#82682 12/08/0211:50 AM12/08/0211:50 AM
Harold, Why isn't the meter accessible? Even a sealed meter meets the defintion of Accessible as applied to wiring methods. In this area the grounding electrode connection from a ground rod is almost always made in the meter can for a residential service. Don
Harold, I have to agree with Don and GJ, the meter is accessible. I have always made this connection in the meter in residential sevices, but in all the areas I have worked, it is, or was accepted by the utility.
I would prefer this lightning braceing to be outside the house. IMHO
If you were to encounter a facility with locked electrical closets, it would probably be as, or more difficult to access the GEC. In reality when would the GEC need to be accessed?
Now back to the original question, if you are attaching the GEC to the panel, I would run it without going through the meter.
[This message has been edited by Roger (edited 12-08-2002).]
You mentioned running 4 wire from meter to panel. Is this a 3W 120/240V system?
Have made some calculations where, 5 feet of RMC, EMT, Alum RMC, and RNC have been the conduits between the meter and the Main-panelboard and a #6 GEC to a ground rod from the meter and a #4 GEC from the panelboard to the water grounding electrode and assumed 25 ohms between the ground rod and the underground water electrode.
For a 200A Residential 120/240V 3W 1Ø Service and using 2/0 Copper in the raceways as noted above, for a 30 ampere unbalanced load ( where one of the Ungrounded conductors carries 30A more than the other ungrounded conductor, thus the grounded conductor [ neutral ] is carrying 30 amps) the:
RMC carries about 48 percent of the 30 Amps and the 2/0 copper about 52 percent.
EMT carries about 27 percent of the 30 Amps and the 2/0 copper about 73 percent.
The Alum RMC carries about 78 percent and the 2/0 carries about 22 percent.
and the the PVC carries 0 percent.
The grounding electrode (GE) system as noted above varied from about .003A to about .01A of the 30A parallel paths of the 2/0, the raceway(s), and the GE system.
Metallic raceways do carry an appreciable amount of the grounded conductor current on an "all" metallic raceway service installation as discribed above.
There are Many thousands of such services installed.