# Teflon tape or pipe dope an anode rod?



## Nestor_Kelebay (Jun 17, 2008)

The question of replacing anode rods in a water heater came up in another thread.

My question is this:

How can you use pipe dope or teflon tape on the threads of the new anode rod without compromising the electrical connection between the anode and the metal tank?

I suspect the answer to this question is that if you tighten up the anode rod well, there will always be some metal to metal contact between the threads. If there wasn't, your connection isn't tight enough.

And, the current flow out of the anode rod is so tiny that you wouldn't need a very good electrical connection between the anode and the tank.

Does anyone have any ideas on how best to install the anode rod to ensure good electrical conductivity between the anode rod and the tank?


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## downunder (Jun 13, 2008)

Still learning!
Didn't know that there was a concern for electrical properties on replacing anodes.


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## handy man88 (Jan 23, 2007)

Nestor_Kelebay said:


> The question of replacing anode rods in a water heater came up in another thread.
> 
> My question is this:
> 
> ...


There exists conductive tape, although it may not be meant for plumbing applications.


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## Reilley (Sep 4, 2008)

I don't think this is a concern as the tape or dope would fill the low points of the threads. When I have removed threaded fittings in the past the tape / dope did not cover the entire thread of the fitting.


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## Nestor_Kelebay (Jun 17, 2008)

Yeah, Reilly's right. Whenever I've removed taped connections, the crests of the thread were bare, and all the tape was packed into the thread valleys.

Downunder:


> Didn't know that there was a concern for electrical properties on replacing anodes.


If your anode rod isn't in electrical contact with the steel tank, then effectively you don't have an anode rod. That's cuz the anode rod uses galvanic corrosion to protect the tank. Basically, it corrodes instead of the tank (just like the zinc coating on galvanized sheet steel protects the underlying steel from corrosion). And, to have galvanic corrosion you need three things:

1. two different metals
2. those two different metals also in electrical contact, and
3. those two different metals also both in contact with the same electrolyte to complete the circuit

If you don't have all three, you won't have galvanic corrosion of the anode, and so no galvanic protection of the steel tank. So, having electrical contact between the anode rod and the steel tank is critical. Without it, you may as well have a steel plug in the hole instead of an anode rod.

That's why I was concerned about the teflon tape or pipe dope interfering with that electrical contact.


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## Mr. Mint (Dec 4, 2020)

Nestor_Kelebay said:


> The question of replacing anode rods in a water heater came up in another thread.
> 
> My question is this:
> 
> ...


I typically use the white pipe joint compound because it can be used with gas as well as water. When applied, it prevents gas or water from worming it's way through the threads and leaking. In other words, the male and female parts are not fully engaged due to irregularities in the manufacturing process. Be assured that when a joint is fully tightened, the compound is squeezed into the voids and there is still a metal-to-metal contact at the pressure points. Again, the compound only serves to fill in the voids between threads to prevent leakage and does not become an insulator. To help visualize this, there is a battery grease available that is placed on automotive lead-acid battery posts to block contact with air and prevent corrosion. When the wiring clamp is placed over the post and then tightened, an electrical connection is still made. The grease does not become a thin insulator and only serves to block oxygen from entering the voids between clamp and post.


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## bfrabel (Oct 22, 2017)

These other guys are right, in that using teflon tape or pipe dope _shouldn't_ be an issue with electrical continuity, but I like to use anti-seize as my pipe dope in situations where I'm worried about maintaining electrical contact. I often do this trick when installing probe-type low water cut-outs in boilers. Anti-seize is made out of either aluminum or copper, depending on which kind you get. My theory is that it will actually help what you are trying to do, instead of hinder it.

I don't know if anti-seize is NSF listed for use with potable water though, so use at your own risk. Although now that I think about it, you probably shouldn't be drinking teflon or whatever normal pipe dope is made out of either.


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## piperpa28 (9 d ago)

Nestor_Kelebay said:


> Yeah, Reilly's right. Whenever I've removed taped connections, the crests of the thread were bare, and all the tape was packed into the thread valleys.
> 
> Downunder:
> 
> ...


There is no electrical connection on an anode rod. It is there to sacrifice itself, instead of the tank. The only leak would be water and tape will help seal it, and make it easier to install and remove next time.


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## chandler48 (Jun 5, 2017)

@piperpa28 you are responding to a 13 year old thread. I think that is a record around here. Check the dates, please.


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