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water heaters and grounding  Rating:  Rating
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 Posted: Tue Jun 1st, 2010 11:59 pm
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mikef135
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I thought I would post the following from a post I wrote in another forum ... my water softener guy was insisting that my water heater failure / anode rod consumption had something to do with electrical grounding.  Don't have all the answers but he did call this correctly in terms of me having an issue I could point to.


"Thanks for making me think about this (in general). Getting back to the electrical I analyzed my personal situation further.

Traced out the point where the copper pipe connects to electrical ground wire at a saddle type connection right behind the cold water shut off valve. It appeared kind of ugly so got ready to probe with my multi-meter ... the damn thing was just sitting there loose!

Thinking back I know when it happened. We've been in our home about 10 years now. During the first year the hot water heater was covered under one of these home warranties paid by the seller. So they came out, proceeded to wiggle the drain valve and flooded my garage. They then removed the existing water heater and came back the next day to finish the install. I remember these 2 guys were having major problems trying to solder a new cold water valve into place. I faintly remember them loosening that grounding clamp to help with the soldering. Apparently 3 water heaters later (plus an inspection I had to pay the city to do) nobody caught the original screw up.

Anyhow, I tightened it up, lightly filed at the wire and copper pipe so I could check for 0 ohms and hopefully things are better. Thank you Gary. Also wondering if my leaky pipe in the wall right next to the water heater was due to this issue."

I also bought a powered anode rod from you guys.  Hopefully my hot water related issues become a thing of the past!

Thanks,

-Mike

edit 6/4: I had almost forgotten my other story regarding grounding ... this is about 5 years after the incident above.  When I had my water softener installed I knew the ground line would be broken (plastic softener valve) and made specific mention to the plumbers to be sure to re-attach that ground path.  They did an excellent job installing the softener itself and the drain but managed to botch the ground connection ... I poked at what they had done and it fell apart!  I called them back and they did it right (3 strands of #12 twisted together between two ground clamps) ... all the while I had the issue above so it didn't matter much anyway for the last 5 years at least.  Guess the moral of these stories are be hyper vigilant in checking electrical (or having an electrician come out) after a plumber messes with your house! ;)

Last edited on Fri Jun 4th, 2010 07:10 pm by mikef135

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 Posted: Wed Jun 2nd, 2010 07:29 am
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eleent
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Hello:  There is likely a little more to it and understand I'm more plumber than electrician :P  Power coming into the house should consist of two hots and a third, neutral line.    Usually the metal cold water line and gas lines are bonded and joined to the ground bar in the main panel which is also hooked up to the neutral bar.  My plumber's understanding is that ground and neutral are basically the same thing with different purposes.  One is meant to conduct power while the other is a safety.

In any event, you likely have a good connection to the neutral at the main panel, but the path to it is worth checking.  I would also jumper between hot and cold with a #6 solid copper wire over the heater. Lastly, there should be a ground rod near the main panel and a #6 wire should be going from the ground bar in the panel to the ground rod.  In recent bad old days, piping was used as the ground :?

Done right, these things will get rid of stray current corrosion, which is when current has the option of going through the heater rather than directly to ground.  If you do measure stray current, best track it down and fix it.  Do talk to an electrician about all this and  should anybody be able to clarify all this electricity for the plumbers amongst us, it would be appreciated.

Yours,  Larry

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 Posted: Wed Jun 2nd, 2010 03:24 pm
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mikef135
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Thanks Larry ... I'm actually an EE but I've been in digital design so long this stuff is pretty challenging to think about now that I have a reason to. 

Thanks for the idea about the #6 jumper ... this would help to channel some of the stray current on the hot side pipes (my existing jumper to ground is on the cold).  A portion would still go through the water heater.

In my home we have underground service to the main panel.  There is no water line anywhere near that main panel due to how the water is laid out in my home.  That is why it makes the bridge at the water heater.

Here is my current theory in talking with the water softener guy about why these stray currents are responsible (in some part) for taking out conventional anodes.  I think the true purpose of the anode rod is to deal with the normally generated stray electrical currents in the tank due to the moving water (which corrode the steel if they don't flow in the right direction).

"P.S. - in your last post I think I finally understood what you were saying about the TV and the stray voltage.

I believe you are referring to the TV antenna (any type). If it is grounded to the cold water pipe then some percentage of the stray current will travel back to the water heater and a greater percentage should go back to the main panel since it is a better ground (in theory - unless there is some problem at the main panel) .

A normal TV should follow the ground path directly back to the main panel (unless the ground there was bad) in which case it could find ground at the water heater (by looping thru the main panel and out to the water heater). At least this is how I understand my homes wiring.

The more current that finds ground at the water heater increases the anode (rod) to cathode (steel) reaction thus consuming the anode rod. The steel itself being the ground that the current is finding. I imagine the EC of the water (slightly higher in my softened case - 1mS vs 0.8mS) does help the current find it's path better but the root problem is the current itself. Aside from those electrical currents generated normally by the moving water inside the tank. Then the question becomes how much "normal" electrical current is generated by moving soft water vs hard water. IE: magnetic field creates an electrical current. Confusing to quantify - could be a wash.

Anyhow, I did ground my HDTV antenna I bought awhile back to the cold water line. Probably not a great idea although I will soon have an endless supply of current to replace the reaction of a normally consumed anode.

From the powered anode guy:

"An impressed-current anode replaces that reaction by introducing electricity into the water heater. Very, very low current. Interestingly, where a sacrificial anode is rapidly consumed in very conductive water, a powered anode has to work less hard because it is so easy for electricity to flow through the water and protect exposed steel. The device is self-adjusting.""

Thanks,

-Mike


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 Posted: Wed Jun 2nd, 2010 04:27 pm
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mikef135
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P.S. - if rogue current does make it's way into the tank it would tend to flow in the same direction as the current originating at the powered anode.  And probably make the powered anode work a bit harder depending on the direction of the rogue current and it's strength!  I'm trying to picture a 3D image of the electrical currents in the tank itself ... easier to think in terms of electrical current than voltage.

edit: my house was built in 1972 w/ no visible grounding rod ... I must have this:

http://en.wikipedia.org/wiki/Ufer_Ground

edit again: and more info on why the jumper from hot to cold on the water heater is needed ...

http://www.homebuyeradvocates.com/PDF/water_pipe_bonding.pdf

-Mike

Last edited on Wed Jun 2nd, 2010 06:41 pm by mikef135

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 Posted: Fri Jun 4th, 2010 12:41 am
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mikef135
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eleent wrote: Hello:  There is likely a little more to it and understand I'm more plumber than electrician :P  Power coming into the house should consist of two hots and a third, neutral line.    Usually the metal cold water line and gas lines are bonded and joined to the ground bar in the main panel which is also hooked up to the neutral bar.  My plumber's understanding is that ground and neutral are basically the same thing with different purposes.  One is meant to conduct power while the other is a safety.

In any event, you likely have a good connection to the neutral at the main panel, but the path to it is worth checking.  I would also jumper between hot and cold with a #6 solid copper wire over the heater. Lastly, there should be a ground rod near the main panel and a #6 wire should be going from the ground bar in the panel to the ground rod.  In recent bad old days, piping was used as the ground :?

Done right, these things will get rid of stray current corrosion, which is when current has the option of going through the heater rather than directly to ground.  If you do measure stray current, best track it down and fix it.  Do talk to an electrician about all this and  should anybody be able to clarify all this electricity for the plumbers amongst us, it would be appreciated.

Yours,  Larry

Also think this "stray current corrosion" issue deserves a mention at your web page in the interest of keeping heaters out of the landfill.  It is pretty insidious and deserves mention as you don't typically think of a natural gas water heater as an electrical appliance (even though it is technically on the "ground circuit").

http://www.waterheaterrescue.com/pages/WHRpages/English/Longevity/what-kills-water-heaters.html

edit: in addition this could be partially responsible for some powered anode failures over time or on a shorter term ...

Last edited on Fri Jun 4th, 2010 12:45 am by mikef135

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 Posted: Fri Jun 4th, 2010 03:23 am
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elenano
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Actually, I think you have a point. I'll probably add something to that page soon. As to powered anodes, only one so far has failed after it was installed. I'm neither an electrician nor a Larry Weingarten -- who gets tired of me bragging about his knowledge:cool: -- but I'm not sure it would have any effect on them.

Whatever, do remember that the water heater makers put anodes into water heaters, not to protect against stray current, but against exposed steel inside the heater rusting. The reaction that results when the heater is filled with water is what protects and is what causes anodes to be used up. Softening speeds that reaction.

Randy Schuyler

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 Posted: Fri Jun 4th, 2010 04:15 am
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mikef135
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yeah, the end result is they don't want rust ... but the currents either help the situation (by flowing from anode to cathode) or hurt it by running in different directions to that ...

take the anode rod out completely and there will be currents present even in the absence of strays ... I think they will then run from steel (anode) to copper (cathode) and if the water is hard you have some trace metal there too.

you can take a crack at Gary on the water softening issue!  I'm keeping an open mind on all of this.  :)

On my 0gpg soft water the EC is ~1mS as measured by my Hanna DIST 4.  The EC of the hard water from the city is ~0.8mS.  So in my test case the soft water is 20% more conductive than the hard water.  Your statement that "softening speeds that reaction" appears true in my case.  EC can easily be converted to TDS but seems easier to think about this with the name "electrical conductivity" 

That was at room temp, the conductivity goes up with heat but would for both cases ...

Read the following article from Rudd/Rheem ... this one is pretty good ... distilled water (the softest of all) has nothing there to conduct! 

http://www.globalimageserver.com/FetchDocument.aspx?ID=9be6139a-8aa9-45b1-882b-ddfb56bfed3e

"What can you conclude about soft water and water softeners from this experiment?
1. Soft water that does not contain enough mineral content to be conductive will not allow the proper electrical reaction between the anode and the steel tank (cathode). If there is little or no electrical reaction between the anode and steel tank, then the tank will not be protected. If the tank is not protected, it will rust sooner than designed.
2. The softer the water, the less ability for the proper electrical reaction to occur. In ‘dead soft water’ (like distilled water), the anode is completely ineffective."

anyhow, still more to think about!

-Mike

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 Posted: Fri Jun 4th, 2010 05:42 am
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eleent
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Hello:  To clarify one thing; there is soft water and there is softened water.  Soft, or naturally soft water is rain or snowmelt or other water that naturally has little other than water in it.  Softened water is hard water that has had the mineral hardness replaced with sodium or potassium.  These two types of water are not anything alike.

Yours,  Larry

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 Posted: Fri Jun 4th, 2010 05:46 pm
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mikef135
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eleent wrote: Hello:  To clarify one thing; there is soft water and there is softened water.  Soft, or naturally soft water is rain or snowmelt or other water that naturally has little other than water in it.  Softened water is hard water that has had the mineral hardness replaced with sodium or potassium.  These two types of water are not anything alike.

Yours,  Larry

Thanks Larry,

Yes ... the definitions and how people interpret them really do further confuse this issue! :?

Here are my current conclusions:

1) True soft water (rain, snowmelt, RO, distilled) would cause very little deterioration of the anode rod and would give the hot water tank little protection

2) True hard water (not machine softened) has enough TDS or high enough EC to protect the tank.  The perfect hard water for the water heater would be the water that has enough TDS to protect the tank and give a light scale but not too much.  Although nobody really wants a light scale on their tubs, toilets, dishwasher, etc.

3) Machined softened water raises the TDS some and this varies (in my test case 20%).  So to me that says the anode rod would deteriorate somewhat faster.  If the softener was malfunctioning it could really crank up the TDS and take the rod out in record time.  I think water softeners malfunction typically because people don't use enough salt (at regeneration time) to exchange out all the hardness that will come before the next regeneration and then the resin itself gets clogged over time.  Although I'm sure there are a bunch of other reasons why they malfunction. 

4) Bad grounding on the water lines lets stray current into the tank.  In my homes case with the bad ground on the water lines to the main panel the whole of the copper plumbing became one big antenna with the water heater as one of the main grounds.  Electrical currents can ride right in on the water itself as it is conductive.  The dielectric nipples on the water heater ports help somewhat but it still gets in.  Once it gets in the current tends to flow in the direction of the already established currents from anode rod to cathode (steel) unless a really big shock but I think we are talking low levels here over time.  Increase the current flow from anode rod to cathode (steel) and the rod deteriorates faster.

I think the powered anode rod could easily deal with a machined softened water TDS malfunction (as now the current flows easier).  I suspect it could also deal with some level of bad grounding ... the low levels of stray currents riding in would flow toward the steel rather than away from it (following the existing currents setup by the powered anode).  But best to fix all this to be safe!

-Mike

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 Posted: Sat Jun 5th, 2010 05:25 pm
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eleent
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Hello:  I think we're essentially in agreement.  Here are some links to relevant articles on grounding and stray current.
http://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/grounding.pdf
http://en.wikipedia.org/wiki/Stray_voltage

The tank can be fully protected from stray current by jumpering from hot to cold and by running an adequate ground back to the main panel, which should then be grounded to earth.  You'll see some discussion of "single point grounding" as a way to prevent stray currents.  Give that electricity some easier path than through the heater and it will take it :cool:  Grounding through plumbing is a poor method of conducting business and has problems, like new plastic pipe being installed!  Still, it makes sense to ground/bond metal lines as proximity to power lines can induce a current into the pipes and cause trouble.  It's interesting to go around with your meter and see what currents are lurking in the plumbing :D

I have read about and also seen anodes completely consumed in six months from over-softened water.  The only point where we don't seem to see it the same is on stray current accelerating anode consumption.  It may be true, but by mixing in softening at the same time there become too many variables for clarity.  It's different for pipeline corrosion, where the effects of stray current on cathodic protection are well known.

Being a hands on type, I'd simply fix grounding problems first and then see what problems remain.

Yours,  Larry


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 Posted: Sat Jun 5th, 2010 05:44 pm
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mikef135
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Larry - agreed on the clarity - too many variables (and theory vs practice jokes)!  What is your definition of "over-softened" water?  This was a major contention issue with the softener guy.  You either have machine softened water (all the hardness is exchanged for sodium) or you have hard water.  His point being there is no way to over-soften.  This really makes sense to me as once all the zeolites collect the calcium then new water coming in would become hard.  Doesn't seem to be a way to partially soften - it's like an exponential function ... soften, soften, soften, and then clog.

Thanks,

-Mike

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 Posted: Sat Jun 5th, 2010 06:41 pm
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eleent
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Hello:  According to the corrosion engineers, you need to leave 60 to 120 ppm of hardness in the water to prevent damage to all things metal.  Go ahead and soften to zero if you must, but build in a bypass to mix in untreated water so hardness can be kept in the right range ;)

Yours,  Larry

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 Posted: Sat Jun 5th, 2010 08:48 pm
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mikef135
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Thanks again Larry - I cracked open the manual for the softener control valve and there is a mixing valve on the outlet side should I wish to experiment. 

Anyhow, here is the "industry response" and what their "corrosion studies" are showing:

http://www.wqa.org/sitelogic.cfm?id=366

I think this may be another one where there are really just too many variables to make any blanket statement and you can argue either side depending on your experience and what the incentive is to you (or the group) personally. 

Out of curiosity which corrosion study are you pulling this "60 to 120 ppm" range from?  I am assuming it is from one of the "corrosion engineering" sites you referenced earlier but a direct link to the article/study would be appreciated.

Thanks,

-Mike

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 Posted: Sat Jun 5th, 2010 10:55 pm
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eleent
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Hello:  NACE sells this item, TPC 7.  Here's a link.  http://web.nace.org/Departments/Store/Product.aspx?id=fa194821-2d74-4575-a64f-7547aadeb2f9 

  

NACE Store - TPC7 Prevention and Control Water Caused Problems Welcome   |   About   |   Update Personal Profile   |   Access Purchased Electronic Files   |   Search

View shopping cart contents...
Items: 0   Total: 0.00


Prevention & Control of Water-Caused Problems in Building Potable Water Systems, TPC 7, Revised Edition This revision of TPC 7 provides plumbing design engineers with the information to overcome water-caused problems that reduce efficiency and shorten the life of domestic water systems in buildings. 1995 by NACE, 6” x 9”, softbound, 84 pages, four figures, index, extensive bibliography
 
  • Product Number:   25007
  • Author:   Prepared by Task Group T-7G-2
  • ISBN:   187791486X

  • Prices Member Price: $26.00 Non-Member Price: $34.00 Your Price: $

    I know it's in the booklet, but don't know where the info is free on the web :?

    Yours,  Larry


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     Posted: Sun Jun 6th, 2010 01:03 am
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    mikef135
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    Thanks Larry - got it on order! :)

    I'll give it a read and make the determination to mix or not to mix ... I haven't touched that valve in 5 years since the softener install so leaning toward the don't fix what ain't broke rule (was it broke - did you touch it? flowchart!)

    Just finished my powered anode / better water heater drain / better ground install ... all went smooth ... I will post some pics in another topic.

    Thanks,

    -Mike

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     Posted: Thu Jun 10th, 2010 10:03 pm
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    mikef135
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    Just wanted to follow up on this one.  I read over the NACE TPC7 booklet.  The section of interest is loosely worded:

    IE: near 0 "softened water *may* be quite corrosive"

    and this one regarding the 60 to 120mg/L as:

    "usually insufficient to form appreciable scale" :D

    It's not a lie but the more I research this I believe this is really a context issue as to whether you will have a problem or not.

    From my current understanding this LSI determines how scale (IE: calcium/magnesium hardness) dissolves or builds up but not how something like copper pipe dissolves.

    If you have really acid water (low pH) and then no scale protection then I would agree.  Add some reducing bacteria on top of this, some stray current, some high temp, high velocity water and then I would really agree on the corrosion.

    Anyway, we are on city water and the pH going in and out of the softener is high.  Chlorination of the city water should help with any reducing bacteria.  We did get a leak in a pipe near on the output side of the heater awhile back (4 years ago) - my guess is the softener pulled all the existing scale out of the lines thus exposing the weak pipe or it could have had something to do with the bad grounding.  Anyway, for a brand new install of a softener this might be something to consider but my pipe scale has been cleaned out by the softened water by now after 5 years.

    Turns out I was wrong about the Clack WS1 softener valve I have ... the mixing valve is optional (at purchase time it seems) but I can put one on pretty easy if I wanted:

    "Drill out the 1/4" MPT fitting on the plumbing connectors and use 1/4" tubing and a ball valve between them."

    I don't see any blue-green stains anywhere.  So for anyone reading this here is my current configuration of things:

    1) San Diego City Water
    2) High pH water from City
    3) Powered Anode in water heater
    4) softener setup for 0gpg using cheap solar salt
    5) ground issues resolved best I can tell

    I also read some other info (also talked about in TPC7) that recommends testing the output TDS from a water softener to insure it does not vary much from the input water.  I found a post that was helpful - talks about not letting the TDS/EC get over 10% variance from input to output or you can have excessive wear issues with a non-powered anode rod.

    http://softwateradvice.com/archive/index.php/t-333.html

    Anyhow, going to leave the softener at 0gpg (no mixing valve) and keep an eye on things.  Based on my situation I think it will be fine. 

    -Mike


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