Quote:
Originally Posted by phrarod
Hi Danny.
That's a lot of wire from the outlet to the mains.  Will my DMM be able to do that?
If you look at the pictures the crazy thing is if you see at where the mains ground connects to that water pipe its all painted and corroded. I can't imagine it making a good ground. Apparently the cable tv people felt the same and ran line to the top conduit from the street coming into the mains. As shown in the picture. Trouble is that same grounding go back to that shoddy water pipe coupling. That water pipe continues under the building and then is coupled with a sewer pipe. I could ground under the house where the copper pipe is right? Seems like it would make a better connection. Otherwise I would use the same place as the cable TV people grounded theirs. That conduit above the mains power doesn't carry any voltage though. Its shouldn't I wouldn't imagine. |
Turn off the main when convenient (very important! Some services don't carry a grounding conductor from the pole to the service. You could get between some nasty current if you leave stuff in the house on) and take all that stuff apart and wire brush the heck out of it, replace old copper plumbers tape type connectors with cast bronze available from the big orange box. If you are using the street entrance water pipe, I would use a suplimental ground rod at the service entrance. The underground pipe is probably corroded by now. A ground rod never requires bigger than #6 solid wire connection because that's all the energy the ground rod can dissipate. So tie it in at the panel. Your panel probably uses the same buss for both white and bare copper wire. As long as you are in there, add a ground only buss and scratch off the paint and attach it to the panel. Run the ground rod grounding electrode conductor to that buss as well as the water pipe ground. Someplace between the service entrance and the first disconnecting means the neutral and the grounding electrode conductor are tied together. That's the most important connection in the house. In the USA anyway. In Europe they have a ground but I can't imagine why, both legs float from ground I think.......maybe they are grounding one in UK now. I forget. Some European backwaters like (never mind) may still have floating services. They carry the ground for RF shielding but not for short circuit protection.
Most US engineers P&M about the lack of a grounded conductor but theory wise it works just fine. I shouldn't be so disparaging, there are good arguments for both situations. Especially the European standard 234 volts. Much more efficient.
So clean it all up, add a supplimental ground, change to a separate ground buss in the panel, and run a wire from it (strung daisy chain, that's the way it was done up until about 67 or 68) to every metal box in the house. Watch out for Black Widow spiders. Leave all that sewer pipe grounding in place. Porcelain doesn't conduct very well, even full of dirty water. And don't hold on to your old ungrounded appliances while sitting on the stool.
Yes your DMM on low range will work.
Last edited by airboss; 11th May 2010 at 02:05 AM.
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Any electricians on the board?
