Grounding Rod vs Cold Water Pipe


Old 05-12-01, 09:52 AM
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Currently my 51 year old house has a ground to the fuse box via a copper wire (albeit smaller than I'd think needed-10 gauge?) to the cold water input to the house.
Do I need to add a 8' copper grounding rod?
I do plan on making some minor changes to the electrical system, and I was wondering if leaving the grounding based on the water pipe is long-term OK, or if I should pay to have an electrician (8' is a LONG drill bit!) put one in?
Old 05-12-01, 01:20 PM
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your H20 pipe is miles long, much more earth contact than an 8' G-rod, it has long been known to be very low ohms. For puposes of safety, the NEC would like more than 1 point of earth contact ( don't wan't to put all yer eggs in the same basket) so a G-rod ( do 2) will suppliment this nicely. Use a #6 bare cu for 100A, a #4 bare cu for 200A.

good luck......
Old 05-14-01, 10:55 AM
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Location: Fayetteville, NY, USA
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If you do not upgrade your service panel you are not required to install a grounding rod, as water pipe ground was legal at the time it was installed. It is a fairly simple matter to add a ground rod though. They drive in much easier than you would imagine, unless you have extremely rocky soil or shallow bedrock. I stood on a stepladder, grabbed the top of the ground rod firmly and jumped, and the rod sunk in 4 feet immediately. With a 3 pound hand held sledge I was able to drove it the rest of the way. You will need some hardware. Home Depot sells this stuff. You will need a ground rod clamp and two water pipe clamps. Use bare copper grounding conductor of the gauge recommended by wirenuts. clamp it to the rod, run it into the house to the main grounding lug in your panel, and from the panel to the point where your water pipe enters the house, and without cutting the wire jumper it around the water meter to the second pipe grounding clamp. Now you're in compliance with the NEC. But again, if the main service is as it was originally and you haven't modified it (branch circuits don't count as a service modification), then you're actually grandfathered into compliance.

Old 05-15-01, 05:32 PM
Christopher Erger
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Here's a trick of the trade.
Tools required: 5 gal. bucket of water, 1 ground rod
Stick ground rod in as far as you can go.
Pour some water around the ground rod.
Move ground rod up and down a few times till it goes
Works really slick and no hammer accidents.
Old 05-16-01, 05:38 PM
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These guys are right, if existing added ground rod not required but good idea.

Best all around tool to drive a ground rod is a rotary hammer drill, second best over all tool is a fence post driver. Most commonly used would be the fence post driver. Fence post driver is a 2" rigid pipe with a cap on one end then filled with lead. Drive the rod like a fence post until the fence post driver hits the ground and reverse the driver and pound on into the ground with the but end of the fence post driver.

Wirenuts, #8 copper is minimum size to a ground rod serving a ground rod. # 6 copper is maximum size grounding service conductor no matter how large a service you have. The # 6 copper is capable of carrying more current than the ground rod can disapate.

If a water pipe has a direct contact with the earth for a minimum of 10' then this water pipe must be connected within 5' of the entry to the building of that water pipe where in direct contact with the earth for a minimum of 10'.

If a metal water pipe does not have direct contact with the earth a minimum of 10'when metal water pipes are the major plumbing style instead of plastic then that metal water pipe must be bonded with a equipment grounding conductor from the panel to make that metal water pipe one with the grounding system of the panel. This water pipe not in direct contact with the earth is only bonded to make it one entity with the panel grounding system, not used as the grounding source unless the 10' earth contact exists.

If the water pipe is used as required when in direct contact with the earth then a supplemental grounding source such as a ground rod must be installed in case that water pipe is replaced with plastic.

Hope this helps

Old 05-17-01, 04:30 AM
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thanks wg!

----and the highlighter comes out once again!-------

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