Thread: OT-metal pipe plumbing vs grounding?

Bought our present abode 4 years ago, with a lot of fix 'er up work to do. Water heater was a BIG problem. One of the previous owners did some work or had it done, to install the water heater. 10-2 off a 40 amp breaker ran to a junction box above the heater, and the ground wire was left floating. An older piece of 10-2 was patched into the box from the heater, and the ground cut off. All of which worked, But: by the time we bought the place, the heater had set for a year or two unpowered, and had a lot of buildup in the bottom, enough to cover the bottom element. The bottom element had corroded through, and one side of the 240 line was now hot to the shell of the heater. Plumbing was a mix of copper and pvc, and copper lines ran over the duct work for the furnace. End result was all the copper pipe and every heat duct and register had 120 volts on it. The copper plumbing was not grounded anywhere. Not a nice situation.

Pretty dumb thought.........
Why not solder or clamp a piece of wire across the pipes that hook into the water heater
just above the top of the tank. 'Whatever' if any electrical activity that may be flowing thru
the heater is now taking the shorter path thru the wire.....and not the tank
May be a waste of time.........but only 15-20 minutes worth.

Over here grounding of plumbing is far more considered as equi potential bonding. At the end of the day, it does not matter what voltage the plumbing is at, so long as it and all the other metallic + conductive surfaces we come into contact with are at the same voltage. No voltage difference, no current flow no electrocution simple. Hot + cold must be bonded and any stainless sinks or similar must be too, all the more so when ran in plastic pipe.

Over here domestically ground rods are not recommended or common, neutral bonding is the preferred option. Ground rods are a very poor unreliable option, there prone to varying soil conditions, lightening issues and a bunch of other problems. Just banging one in how ever you do it is next to pointless unless you have the test gear to measure the results it actually achieves! That's a legal requirement here when one is used. Untested ground rods are as unknown as pointing a gun at your head and pulling the trigger, it might or might not "work". At least with the gun you know when it will go of, earthing and electrical faults could and do happen at any point in time!

That said grounding could well increase corrosion, caustic or acidic water chemistry + diffrent metals will make a battery, allowing the current to flow between those metals will hasten corrosion (good bonding + metal plumbing connections allow this), its basic science. The fix is to either replace all plumbing with the same metal, then its just how fast that water will eat the pipe or switch to chemical resistant plumbing or do something about water quality.

Originally Posted by jim rozen

"Electricians connect ground wires to water pipes because it is convenient. "

In my area, they do it because it is required by code.

Yeah, that's because the "code" is written by a bunch of greedy electricians.

I have heard electrician's claim that grounding rods are unreliable. It's complete hogwash. The real reason is that it takes 30 seconds to attach a ground to a water pipe and an hour and a half to install a grounding rod.

I admit it: I hate electricians. Of all the half assed and dangerous work I see in houses, most of it is by electricians trying to finish a job faster and cheaper at the expense of the homeowner's safety.

The other reason I hate electricians is because they use set screws, the devil's fastener.

Grounding and Bonding are primarily done to provide a LOW Impedance Path for Fault currents whatever the source so that the source overcurrent device trips and clears the fault. All bets are off when dealing with lightning because that stuff doesn't have a circuit breaker.

Next topic; older (like 30 years) copper water lines will generally corrode thru pin hole fashion on the bottom near the water heater. It happened to me right over my small lathe in the last house. I hear about it regularly from a local realtor that I see daily. The higher the water temperature the faster it occurs.

3¢

Originally Posted by Sea Farmer

Do you have a private well? ...

Yes! and pretty hard too. Yet another reason I wish I had town water... Someday, maybe they'll extend the pipe to our "side of the tracks" ehr.. interstate.

Originally Posted by jscpm

Yeah, that's because the "code" is written by a bunch of greedy electricians.

I have heard electrician's claim that grounding rods are unreliable. It's complete hogwash. The real reason is that it takes 30 seconds to attach a ground to a water pipe and an hour and a half to install a grounding rod.

Then how do you explain that the code requires not only the water pipe connection, but TWO additional ground rods for the typical residential service these days?

You need to achieve < 25 ohms resistance to earth, and in most areas, a single rod isn't going to get you there, so a second rod in parallel (at least 6' away) is usually needed.

Originally Posted by dkmc

Pretty dumb thought.........
Why not solder or clamp a piece of wire across the pipes that hook into the water heater
just above the top of the tank. 'Whatever' if any electrical activity that may be flowing thru
the heater is now taking the shorter path thru the wire.....and not the tank
May be a waste of time.........but only 15-20 minutes worth.

What you suggest is actually required in many localities.

At our home place in Western PA we had a spring and a cistern. Water heaters lasted 2 - 4 years. I was removing a dead clothes washer from the basement and did not notice the ground wire attached to the copper cold water pipe. When I pulled on the washer it snapped off the copper pipe. It was tissue paper thin.

I have since learned that springs and wells in many parts of the country have acidic water and will dissolve metal pipe.

Google "acidic well water and water heaters"

Use ground fault circuit interrupter outlets (GFCI) in the kitchen & bath and at least U ground outlets in the basement and shop.

I was at a friends house and was leaning against the metal sink base rim and reached to open the refrigerator. I got a good whack as the frig did not have a grounded outlet and had a loose wire touching the case.

I have gotten less tolerant of being shocked in my old geezer stage.

Paul

"Yeah, that's because the "code" is written by a bunch of greedy electricians."

Sir I am not overly fond of professional electricans (because of other 'features' I've seen done
locally) but in this case you are flat out wrong.

The code says to BOND to metalic plumbing for EXACTLY the reasons already mentioned: to
prevent the plumbing from developing any voltage that might harm the residents. The 'lazy'
electrican has to ALSO follow the code and put in one or several (depending on the
local soil conditions) made electrodes.

To put this another way, the incoming service entrance MUST by code be have the neutral
conductor connected to a variety of items. One of those is the plumbing. If the lazy
electrican omits that, the residence won't pass the final inspection - at least around here.

Originally Posted by jscpm

Yeah, that's because the "code" is written by a bunch of greedy electricians. Etc., Etc.

Electricians like machinists come in good, bad, and indifferent.

I once worked with an electrician who set me to drilling holes and pulling wire. The hole in each basement joist was marked with a jig exactly one foot in from the band joist and centered on the joist. The wire was unrolled and installed flat, no twists, stapled at closer intervals than code required, down the middle of the joist. Everything was done neatly and at or better than code.

When the electrical inspector came for the final, he walked around and looked, said "looks like XXX was your electrician", the owner said yes.

Inspector got out the green tag, signed it off, put it on the breaker box, and was gone in 10 minutes from the time he came in the door.

Paul

As a qualified electronics engineer, i am technically not a electrician, i am required and have proven to fully understand electrical current flow. Electricians are mealy required - qualified on code knowledge and code following experience here. It's the difference in the automotive world between being a dealer trained service technician and someone that can design a engine from raw principals. Rather than slating greedy code books, you would do real well to understand some basic things, like dry sand is a ceramic and is in certain locations a exceptional insulator, That can be greatly affected by seasonal weather and a host of other random conditions. That can render a ground rod as grounding as it would be sat on a large block of plastic.

Real ground arrays are always designed based on on the ground conditions. Mearly banging 2 rods in and calling it good is akin to taking the final cut on a part and not QC'ing it before using it in a life threatening application. It's out right reckless and would - could lead to a manslaughter charge here. To test grounding performance is not hard and it should be done if your going to provide your ground this way.

Personally i prefer a nicely bonded earth and neutral prior to the meter as per code here. Neutral is tied into a truly "industrial spec" ground array at the substation. What's more this can simply be checked by banging a rod - screwdriver even into the soil at the given property and measuring the resistance/potential between the two, even sub station arrays have - do fail. Often only picked up by tests done by electricians doing installation sign offs at those addresses.

Adama:

The neutral is ALREADY grounded, and BONDED to the box and the earthing wires......

The neutral comes in with the service in most locations (except one-wire services, which are rare here, more common I understand, in Australia). It is earthed at every, or every other, pole, and is re-earthed by the water pipes and the ground rods because neutral and earth wires are "bonded" at the service box. It is pretty safe, actually, hard to see how it could be better.

Jumpers around things which may be disconnected, like water meter, and hot water heater, are required, to prevent one side of the pipe from being "hot" when removing the appliance.

As for water PH, the zone of least solubility of lead in water is somewhere around 9 to 9.5 pH. Most water supplies are forced to that by the EPA to prevent picking up lead to the best of their ability in the "first glass of water in the morning" test...... the typical brass of faucets contains enough lead to leach out overnight and pop the PPM too high to pass..... So the EPA tries to test in the morning before any water is run.

Years ago my wife lived in a house with ground bonded only to water pipes, no rod. Depending on whether the submersibie pump was running (may have been defective or wired wrong), the washing machine would go partly hot. When lightning hit the pump, with no secondary ground, all the plumbing went hot.