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Old 09-22-2012, 03:11 PM   #16
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Analog multimeter shows voltage even with 3-way switch off


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Originally Posted by mpoulton View Post
That's not a good assumption to make. There are plenty of ways to wire things so that they work, and very few ways to do it that are safe. Many of the safety problems in wiring do not show up during normal operation, but only when there's a problem. Often it's not obvious.
Ok but that doesn't quite make sense to me. How can this be a verified, check able occurrence in house wiring but still not mean there isnt an issue? If you could explain exactly how this could be working based on the way we tested but still not be safe or correct at all?


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This is a great example of a safety problem that doesn't show up during normal operation. Grounding has been required for so long now that there's no way it's a code-cycle issue. The rules have changed somewhat on exactly how it must be done, but the general premise has been in place since the early days of electric power. The grounding that the power company is talking about is not the same - you still need grounding and bonding at your panel. Two ground rods, plus bonding connections to the plumbing, gas service, and probably cable TV and telephone.
OK well I guess like always take what one reads on the internet with a grain of salt. That was simply the general consensus I was finding on other sites and forums. But since we are on the topic and its of concern I would like to add further detail to see if this changes the conclusion.

The panel is fed from a single conduit from a metered box. The feed is on 3 high gauge lines. I'm not sure exactly what but it looked like standard, heavy duty, outdoor, cabling, approx a half inch in diameter, "USE Type" I think its called? Two of the lines come into the panel and go to the top of the main breaker for the house. The 3rd high gauge line connects to a large ground terminal strip. Off this strip there are many bare ground and neutral(white) wires screwed into the terminals. A few are shared, yes I am aware this is not to code? and this was per-existing, I have done no work inside the panel, but some minor work was done by licensed electricians. This was fixing the wiring to the Air conditioning to be to code (higher gauge wire and to solid copper with a properly mounted box), and replacing an old 20A breaker that fed some bedrooms.

Looking around inside the basement ceiling I don't see any place that a ground line is necessarily attached to a cold water pipe but there is a thicker braided ground that goes into the house conduit so its possible that is there somewhere and I haven't found it just yet. However, there are no ground stakes at all and no visible ground connection outside of the panel. I do see a ground connection for cable TV that has a single wire going to a junction box for that ground. I haven't seen a gas ground but I was not looking for one at the time so I would have to examine further. Would this be a ground from the outside line or is this an internal connection?

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Old 09-22-2012, 04:10 PM   #17
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Analog multimeter shows voltage even with 3-way switch off


Your earth ground would connect to either a water pipe or a ground rod from the same bar in the panel that has all the neutrals and grounds. It should be 6awg or so. If its missing its a big deal. What your reading around the internet is that in older homes many times there's no grounds run in the branch circuits supplying the various devices in your home. The main panel ground has always been a requirement. It is something that you can likely do yourself with little problem. My familiarity with the nec is limited but the above poster is usually pretty accurate with his code so I would take that as to the requirements you need to do this ground.

To put it in perspective no main ground is like jumping out of a plane with no parachute. A lightning strike will wreck havoc on your appliances and your breakers have no reference point with which to work from. Also you now have no low impedance path for the current to travel on a short circuit and your body(high impedance path) can easily become that path.
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Last edited by andrew79; 09-22-2012 at 04:27 PM.
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Old 09-25-2012, 12:20 PM   #18
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Analog multimeter shows voltage even with 3-way switch off


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Originally Posted by andrew79 View Post
Your earth ground would connect to either a water pipe or a ground rod from the same bar in the panel that has all the neutrals and grounds. It should be 6awg or so. If its missing its a big deal. What your reading around the internet is that in older homes many times there's no grounds run in the branch circuits supplying the various devices in your home. The main panel ground has always been a requirement. It is something that you can likely do yourself with little problem. My familiarity with the nec is limited but the above poster is usually pretty accurate with his code so I would take that as to the requirements you need to do this ground.

To put it in perspective no main ground is like jumping out of a plane with no parachute. A lightning strike will wreck havoc on your appliances and your breakers have no reference point with which to work from. Also you now have no low impedance path for the current to travel on a short circuit and your body(high impedance path) can easily become that path.

Yes I do intend to get the earth ground issue corrected, I am certainly aware that its a major problem. It just boggles my mind how builders can get away with crap like this though.

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