DIYbanter - View Single Post - Grounding question -- ping gfretwell

bud--

On 7/25/2016 7:17 AM, wrote:
On Mon, 25 Jul 2016 12:11:14 -0000 (UTC), Doug Miller
wrote:

My house, built in 1962, has one grounding electrode: the metal plumbing system. Doesn't
meet Code now, but I'm pretty sure it did in 1962.

The NEC is a code for new work. What you have was compliant when
installed and thus has no problem with the current NEC.

I know that current Code:

(b) does not require the metal water plumbing to be a grounding electrode *at all*;

Totally false.

Not true, water pipe shall be bonded

Not true. Water pipe (10 or more feet metal in contact with the earth)
shall be used as an earthing electrode.

If the water pipe is not "10 or more feet" the interior water pipe shall
be "bonded" with slightly different rules.

This must have just been a misstatement. The rest of your answer
indicates the water pipe is an electrode. I agree with everything else
you wrote, including that ground rods suck.

Here's what I propose to do:

(1) Sink a 10-foot grounding rod

The NEC requires the resistance to earth for a ground rod to be 25 ohms
or less. [What happens if you connect a hot wire to a rod that is 25
ohms to earth? Ground rods suck.]

Virtually no one will measure the resistance. A second rod is installed
and the resistance can be anything.

Rods are minimum 8 ft length.