Originally Posted By: rmoore
This post was automatically imported from our archived forum.
Well…here’s something I’ve never seen done before…
[ Image: http://www.nachi.org/bbsystem/usrimages/g/groundedmast.jpg ]
For some reason they have bonded the service mast at the weatherhead, neatly negating the ceramic insulator. There is about 25 feet of exterior conduit to the meter and then about 5 more feet to the interior service eqip panel. The neutral/ground bar is bonded to the panel as is the conduit coming in. The neutral (grounded) feeder was insulated all the way to the bar (where visible). There was a GEC to the water piping only.
This was a 1926 home, still with some KT wiring. I have no idea why someone would have done this...maybe they thought they were grounding the system when they upgraded to a breaker panel. The end result is, of course, paralell paths with the possibility of all the conduit and meter box being used to carry the unbalanced (neutral) current back to the grounded service drop. Not good (but looks like a fairly simple fix for a sparky).
Anyone else seen this?
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