I upgraded my main circuit breaker today from 150amps to 200amps.
See my previous posts here on the same project:
What I missed is ground wire gauge. I had and still have #6 AWG copper wire which was enough for 150amps, but not enough for 200amps. So my inspection with my town failed – inspector has pointed me to this.
My copper ground wire goes all the way through basement to opposite side of house and connects to water pipeline there. I'd like to avoid upgrading that wire that goes in many hidden places (behind dry walls in the basement etc) to #4 AWG.. what I consider doing instead:
- put a couple of rods 6 feet away from each other, but close to the MSP, like on this video – https://www.youtube.com/watch?v=t7FzUUqCdpI ;
- upgrade to #4 AWG just the ground wire from MSP to these ground rods;
- connect #6 AWG that goes all the way to the water pipe to these rods as well.
Would these be enough of grounding for 200 amps service?
If yes, could somebody please reference relevant National Electric Code articles?
I now have to redo the grounding work, and request re-inspection, but I'd
like to avoid rerunning that wire that goes around whole house to water pipeline.
Driving a couple of rods into ground seems to me a much better idea, plus connect to the existing #6 AWG ground line as I described above.
What's interesting I already have one grounding rod and it's already in connection with that existing #6 AWG copper wire.. so I'd like to add one or couple more rods there.
When I brought up this idea to the inspector, he said NEC says if house has a water pipeline, ground wire has to go there. He was kinda opposing my idea of driving rods and making additional connections there (his argument was that AWG gauge for ground rods can't be more than #6 AWG). And again that's despite that I already have a similar grounding setup with a grounding rod.
Any help will be greatly appreciated.
Best Answer
Your inspector is wrong. You can always use a larger ground.
NEC article 250.66 covers this in depth.
In fact, the code handbook (an expanded code book good with explanations of what the code is requiring) has a great exhibit 250.30 which shows connections to grounding electrode systems. 250.66.A states the connections to rod, pipe or plate electrodes is not required to be larger than #6 copper.
if your existing connection goes from the rod directly to the service panel only #6 copper is required. If the system connects to a concrete encased electrode from that point (point of connection to the concrete encased electrode) to the panel #4 copper is required to the panel, but #6 or larger from your ground rod to the panel or point of connection with a concrete encased electrode is all that is required.
I use #4 solid copper all the time as most new construction has a connection point with the foundation rebar, and then a second method (driven rod) is connected. Since I already am using #4, I run the couple of feet outside and connect the rod with a listed clamp, all on 1 piece of wire.
It is OK to go larger but not required.
This method is code-compliant for up to a 400 amp service.