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Don Y[_3_]

On 12/8/2015 10:34 PM, wrote:
My 1950s era house had a 100amp panel, with a grounding wire that ran to my
well and was clamped to the well casing. I hired a licensed electrician to
upgrade to 200amp panel. He also installed 2-3 ground rods outside the
house and connected from the new panel to them, AS WELL AS running from the
panel via a heavy wire (looks like #6 aluminum strand) clamped to the copper
water pipe downstream of my pressure tank. Notice... he didn't connect to
the well casing, but to the piping on the "house" side of the pressure tank,
and the pressure tank is separated from the well casing by my pump and black
rubber hose (i.e. no electrical continuity). And he left the original
ground wire as-is on the well casing.

Never noticed all this until recently. Is this correct? Shouldn't there be a
jumper cable to connect across the black rubber hose (from the copper pipes
to the well casing?)

The electrician is ensuring your house's *plumbing* is grounded.

Ages ago, houses picked up their "local earth" *through* the
water main. But, there are problems with that approach:
- the water meter can be removed which "opens" the connection to earth
(so, run a jumper across the meter's location to ensure galvanic
continuity even in its absence)
- whole house filters and softeners pose similar problems
- the water main may not be metallic (or for only part of the way)
- the interior plumbing may contain sections that are non metalic
- water pipes corrode (and, can do so at any place, not just one
that might be convenient electrically!)

The grounding rods ensure a reliable connection to earth regardless
of the state of the plumbing, water main, etc.

The electrician has no way of knowing if someone expected the
plumbing to have been this source of earth, previously. So, he
intentionally connects the plumbing to this "reliable earth"
that he has created to ensure any connections to those pipes
will make it to earth.

For similar reasons, a metal frame building would *also* find
an explicit connection of the building frame to that earth.

[Ductwork is required to be grounded in some commercial
settings to control the build-up of static charge]