Grounding

[Billy B]

I am not talking about the kind that happened to me so often as a teenager...

What is considered "ground" besides the green wire in electrical circuits? What fits the criteria so that I can know conclusively that something is grounded...like my dust collecter pipes, there are no water pipes that run through my garage, and why are pipes considered grounded anyway, are they connected somehow (for a lack of a better term) to the cable sunk into the ground just below my electrical panel?

Thanks,

Bill

[MatD]

I believe that the modern electrical code requires that all water/gass/and cable be grounded (to the ground rod outside your service panel).
To say that something is grounded means that the electrical current has an alternate path to 'ground' itself if there is a short circuit (ie instead of through you). As far as grounding to a water pipe, if they aren't grounded to your ground rod, then they are usually grounded because they through the ground (and therefor, are grounded). Using a waterpipe as a ground isn't up to current electrical codes but it does work (you will need to use a wire to 'jump' the water meter though).

Mat

[TDHofstetter]

Hey, Bill...

Grounding is accomplished within the house proper through the uninsulated (bare) wire in your home's wiring. Supposed to be, anyway - if you have real three-wire wiring to your outlets. Within electrical equipment, it's usually done with a green-insulated wire. Just to confuse matters, I suppose. :)

To know conclusively that "something" is grounded, you pretty much have to drive a ground rod yourself outside the building into relatively moist soil that can be counted upon to stay relatively moist year-round, then have yourself run a fairly substantial wire (usually bare) from that ground rod to your "something" and connected it firmly with a gas-tight connection to an integral metal part of that "something".

Lacking the wherewithal to drive the ground rod and run your own ground wire, you can usually (usually!) count on a bare wire from your breaker panel to be grounded. They're SUPPOSED to be properly grounded. Likewise, there really SHOULD be a ground wire running from your telephone interface box to a good earth ground somewhere.

If you have two-wire wiring but can verify that the ground bar in your breaker box or fusebox is grounded, you can run your own ground wire from that ground bar to your "something". If you already have a ground cable running from your current (no pun intended) panel into the ground, and if that cable isn't carrying electrical power into the box, it's probably a ground cable - and it's probably good. Especially if it's not insulated.

While most pipes are considered to be grounded, all are NOT - and of those that ARE, some are not to be considered a "good" ground. Hot-water pipes aren't necessarily grounded because some water heaters isolate them from the cold-water plumbing. Even cold-water pipes aren't always grounded - some are isolated from earth ground by a stretch of PVC. Some cold-water systems are entirely made of of PVC. You can't get a good ground through PVC pipe...

Gas pipes, while they may be grounded, should never be used to ground anything electrical. In the event of a serious problem, you do NOT want arcing anywhere in the vicinity of a natural-gas pipe!

Your DC pipes are probably OK if they're not grounded. If you insist, though, you can get comfortable if they're made of metal or have a full-length drain wire inside them - and at least one end is electrically connected to an electrical device which is itself grounded through a correctly-terminated 3-wire outlet.

If all else fails, you CAN always drive another ground rod outside the shop. They aren't very expensive, and they aren't very hard to drive, and they do a good job. Use the approved grounding clamp to connect your bare or green ground wire from the rod to the equipment. Bigger is better, and there are NO drawbacks to using oversized wire for grounding. Try to use wire that is as big as, or bigger than, the wire supplying power to your equipment. If the equipment is fed from 12-guage wire, make your ground wire at least 12-guage.

-- Tim --

You can always take one more step against the wind.

[jimpen]

Just to throw some more confusion into this.....

In a portion of west Texas they had coliche. While typically very dry, it had such a high iron conent that the local electrical code dropped the grounding stake length to half the national standard. Besides, about 8' down, if you were lucky, was where the solid granite started. If you were unlucky, it was only 3'-4' feet down.

[deathwish2]

>Using a
>waterpipe as a ground isn't up to current electrical codes
>but it does work (you will need to use a wire to 'jump' the
>water meter though).

Also, you'll need to 'jump' over any filters or softeners in your system. In my home the power box is grounded to an outdoor spike (was likely done when the panel was replaced in the late 80's/early 90's shortly before I bought the house, because you can see where it used to connect to a pipe). But, the phone service ground still goes to a water pipe, and I installed a whole house filter . . . which needed two clamps and a bare wire to 'jump' the ground over to the other side of the filter . . . . in hindsight it would have been easier to just move the phone's ground . . . but at the time, I wasn't sure what else might be one the pipes elsewhere in the house.

--Deathwish

When it comes to
woodworking and buying
tools, I always think back to
my grandfathers advice on
golf . . . "it's not the arrows,
it's the indian.''

[daveferg]

OK, now this has me curious! Talked to an electrician about this, since our water line, turned out NOT to be a ground---sneaky---metal above ground and in the house, but PVC for the main---and, on the water pipe, there was a clamp with phone and another bare wire going to it----I was afraid this was from the service panel ground buss, but the electrician said they useds a metal rod, near the service panel, sunk into and past the concrete foundation---

Does that sound right?

[deathwish2]

Yes it sounds right to me, but it wouldn't hurt to move the phone ground to the outside of an electric box . . . just in case of lightening

--Deathwish

When it comes to
woodworking and buying
tools, I always think back to
my grandfathers advice on
golf . . . "it's not the arrows,
it's the indian.''