Water pipe grounding

[TryintoDIY]

In an older house without grounded outlets, I grounded 2 outlets (in 2 separate bedrooms) by bonding almost 30 feet from entry of the water line. The piping is all copper, including more than 10 feet outside.

There are 4 old valves and an elbow (looks like all brass) along the run and a T junction near the entry before the shutoff valve, and it has a proper jumper around the water meter and valve. Is there any reason to make a run to the entry point or the bus bar in the subpanel besides for the sake of code?

I have a faucet about 5 ft up on the floor above in a bathroom. That is the only potential problem I can even think about, but I believe current would flow towards the run instead of to the faucet.. Then again I could be wrong, hence why I'm looking for answers.

 

[Jadnashua]

I do not think what you did would pass code. If you want most of the function of a 3-prong receptacle, use a GFCI or rewire things with a grounded cable. If you then daisy-chain off of the GFCI (or use a GFCI breaker), you can replace any 2-prong ones with 3-prong ones legally as long as you install the sticker warning that there is no ground, but it is GFCI protected. Last year, I did that through-0ut my mother's house. The over 50-year old 2-prong receptacles were pretty much worn out, so rather than replace them with same, I updated them all with GFCI protection and 3-prong versions.

The safety ground wire should NEVER have current on it except when there is a fault and then, only for a very brief time before the breaker trips or the fuse blows. A GFCI will protect you much better and be code compliant. Bonding to water pipes should only be done when an actual ground plane has been established. FWIW, the ground wire is there to trip the fuse or breaker should there be a line/ground short. Bonded to the water pipe, it might not be a valid ground, and could then be at some higher electrical potential. A GFCI will trip when any current imbalance occurs greater than 5ma, which means some power is going where it shouldn't...a ground wire could allow MUCH more before that happens. There's a reason they make GFCI's mandatory and that they can work without a ground wire - they measure the current on the 'hot' lead, and compare that to what is returning on the neutral, and shuts power off if they are not balanced.

 

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[WorthFlorida]

This should help you out. It the same explanation as jadnashua's but has some more detail if interested.
http://ecmweb.com/content/replacing-2-wire-ungrounded-receptacles

 

[Speedy Petey]

The ONLY time you can use a water line for an equipment ground source is if the water line is metallic, is in contact with the earth for 10' or more, is being used as an electrode, AND the ground connection is made within 5' of where the pipe enters.

 

[Reach4]

The ONLY time you can use a water line for an equipment ground source is if the water line is metallic, is in contact with the earth for 10' or more, is being used as an electrode, AND the ground connection is made within 5' of where the pipe enters.

That is what the code says. OP was wondering about the function "besides for the sake of code?", and that is a tough question to answer.

 

[Bluebinky]

That is what the code says. OP was wondering about the function "besides for the sake of code?", and that is a tough question to answer.

Not a pro, but I vote for don't even bother doing this. If you can manage to ground the water pipe back to the panel, then "maybe", but you didn't hear it from me. You risk energizing the plumbing itself if there is a fault. Like already said, use ungrounded GFCIs instead.

 

[Jadnashua]

FWIW, depending on were you live, and the state of the soil, it's moisture level, and other properties, even 10' make not make a great ground. For most situations, a GFCI protected circuit is safer. Yes, having the ground there can potentially help a little, but the GFCI is safer for people - a poor ground can still have enough potential to be dangerous.

 

[Reach4]

A real ground can make a surge or EMI suppressor more effective.

 

[Jadnashua]

A real ground can make a surge or EMI suppressor more effective.

This is true, as the better ones use three-mode suppression, which includes clamping to ground. But, from a safety viewpoint of people, a GFCI is better.

 

[Reach4]

I think that a ground would be potentially useful in the event of lightening, and that GFCI would not.

I would not want GFI on my sump pump -- despite what the NEC says.

 

[Stuff]

Why are you interested in grounding your outlets? The simplest legal thing to do is to use two-prong outlets.

 

[Speedy Petey]

That is what the code says. OP was wondering about the function "besides for the sake of code?", and that is a tough question to answer.

I don't deal with "besides for the sake of code". NO ONE should when giving advice publicly.

 

[JWelectric]

Electrical systems are connected to earth for four reasons as outlined in 250.4(A)(1) and life safety is not one of them.

An earth connection in no way makes an electrical system safe and does nothing to clear a fault. Using Ohm’s Law we can figure just how much current would flow through earth during a fault. Using 25 ohms of resistance as mandated by the NEC then we would divide this 25 ohms into 120 volts which would only equate to 4.8 amps and nowhere near enough to open a breaker or blow a fuse.

Bonding the equipment grounding conductor to the neutral in the service equipment is what makes an electrical system safe. Now there is a low impedance path for fault current.