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hardwiredman
Sep 29, 2007, 12:00 AM
I am replacing an old 200 amp meter base with a 200 amp meter base with a built in disconnect breaker. From here I will feed the 200 amp panel inside.

My question is about the ground. I have PEX plumbing, but the supply to the house is galvanized. I understand I need to bond the water supply to the grounding system, I have 2 grounding rods 6' apart that will be the main ground. I need to understand where the grounds will connect. If I understand correctly, since the new meter base will have a disconnect, the ground needs to be bonded to the neutral at the disconnect. So does this mean that my 2 ground rods will connect to the meter disconnect and not the inside panel?

If that is correct, then I have 4/0 from the meter to the panel for the two hots, and the neutral is a 2/0. Is this the correct size for the neutral? I read in my code book that the neutral should only be bonded to ground at the first disconnect, so I won't bond it on the inside panel, but my question then is what is connected to the ground bar on the inside panel? Do I need to run another #6 wire from the panel ground bar to the ground rods? And where should the water main be bonded?

Thanks a bunch!

tkrussell
Sep 29, 2007, 05:02 AM
With the main at the meter, the neutral will be bonded to the metal can , and connect both incoming and outgoing neutrals, grounding electrode conductor from ground rods, and an outgoing equipment grounding conductor to the panel.

The feed from the meter/disconnect to the panel must be four wire, 2 hots,1 neutral, and 1 equipment ground, which should be a min of #6 copper or #4 aluminum, insulated. This #6 will connect to the equipment ground bar in the panel, along with all branch circuit equipment grounding wires.

Bonding the water can be done from the panel's equipment grounding bar, to any point of the metal water piping that is accessible.

The neutral can be reduced down to #2/0 if the service calculations have been done, which then shows the amount of neutral current. The neutral can be reduced down to 70% of the mains.


Hope this helps.

hardwiredman
Sep 29, 2007, 12:25 PM
http://www.porterfamily12.com/service.jpg

Is this correct?

tkrussell
Sep 30, 2007, 03:14 AM
Exactly.

hardwiredman
Sep 30, 2007, 10:36 AM
Exactly.

Thank you very much, you've been very helpful.

Stratmando
Sep 30, 2007, 11:40 AM
In addition to above, Noticed bonding screw is out, and should stay out.
We commonly run a #6 to the Cold IN on the water heater. Easy, protected, and accessible.