09-08-16, 06:39 AM | #11 |
Steve Hull
Join Date: Dec 2012
Location: hilly, tree covered Arcadia, OK USA
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My old Fluke meter has that function (conductance, mhos). Some 30+ years ago, I bought a Fluke and was appalled at the "high" price. Worth every penny. The only thing that has needed replacements are a few 9V batteries and a fuse. One rugged work horse.
Oh - and a set of leads when I mistook current for voltage and burned them up. Meter was fine. Had to replace the fuse inside. Steve
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The Following User Says Thank You to stevehull For This Useful Post: | jeff5may (09-14-16) |
09-14-16, 10:58 AM | #12 |
Apprentice EcoRenovator
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Steve;
Incorrect grounding methods were part of the problem, although in our case the phone line was the major culprit. We haven't lost anything major since I pulled down the phone line. On the advice of our co-op field engineer I removed two ground rods that were daisy-chained out to the HVAC units. I then added a second rod at the transformer. He said some residential installations near the lake have four to six rods at the pole where the transformer is mounted. Only one rod should be installed at the service entrance and that one is for safety (per code), not lightening surge. I recently noticed that all new Okuma machining centers now have their own transformer mounted on the cabinet. Each machine has its own ground rod but it is tied directly to the transformer. I guess Okuma got tired of replacing PLC's and servos here in the lightening belt. I've always wanted a mho meter. Probably should have purchased one before I retired. I do check the ground rod clamps about once a year. Doug |
09-14-16, 12:24 PM | #13 |
Steve Hull
Join Date: Dec 2012
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A lot of well intentioned and sometimes poorly trained engineers put additional ground rods throughout an installation. These create ground loops.
Best practice is to put a set of superb grounds at the service entrance. That minimizes ground loops. Steve
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consulting on geothermal heating/cooling & rational energy use since 1990 |
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