Corrosion in RJ11 / RJ45 Connectors

Has anyone encountered corrosion in RJ11 / RJ45 jack / plugs? I think this effect might be mostly limted to areas closer to the sea, high humidity areas, in higher temperature areas and where there might be additional airborne pollutants. Florida and Hawaii come to mind.

Also, the use of voice on the line (with voltages of up to +/- 48 volts

- ?) may worsen electrolytic corrosion - I don't think it's a galvanic corrision effect. Not sure.

I'm wondering what will happen with the planned Power over the Ethernet. That will use 48 volts across pins of the RJ45 connectors.

Thanks for any comments you may have,


Bob Elliot

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On it's own, gold doesn't corrode. However, some connectors might be a bit cheap with the gold.

It's not the voltage that causes that, it's the current that caused the ion migration. Also, higher voltages tend to penetrate the corrosion. I believe the phone companies refer to that as "sealing current".

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James Knott

Seen it in wet locations. Kitchens, laundry rooms, wet basements and the like. The wiping action of plugging it in usually scrapes enough of the corrosion off to make a connection. Of course ones that are gold plated too a sufficient thickness are not going to corrode. Don't buy cheap connectors for these locations. Usually the problem with these connectors are the corrosion inside on the copper wires has caused problems. You can get various compounds for sealing these in your local auto parts store. Look under the battery connector sealing sprays.


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Dale Farmer

Does not have to be Florida or Hawaii: in one instance here in PA all it took was a cleaning lady, who decided the faceplate is dirty. We could not identify the actual solution she used, but the RJ11 plug got totally destroyed. Upon taking it from the jack all the contact material simply fell down in a form of a black powder. That effectively knocked off a digital PBX phone that uses constant 48V (as oppose to "smart" 48V of PoE that you?ve mentioned here). Much less of a contact problem would render PoE circuit dead because before applying the full power an 802.3af power hub/switch sends a weak-current polling signal and looks for a response from the terminal equipment.

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we used to make NTU's for Irish Telecom. Corrosion was a challenge.

You can cover the contact surface with a very thin layer of wax or seal the jack's arperture with a jelly.

Regards Thomas

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Thomas Beneken

As often before your chances off success is better with a quality system.

I only remember a few cases across the thousands of quality connectors I have installed and serviced. All of them could be linked to cleaning or other physical contamination

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You shouldn't allow your connectors to get wet.

I have a problem with 66 block corrosion, caused mostly, I believe, from condensation. The room also has a custodian sink and washer and dryer in it.

I had a problem with corrosion in a classroom. It's the chemistry lab. You know that the jacks and plugs have gold plating, which protects them against corrosion. Well, it takes a lot to corrode gold. I guess the chemicals in that lab must have been vapors from both nitric and hydrochloric acids, which make aqua regia, IIRC. The chairs were up on the desks, and I noticed that the chairs' chrome legs were corroded badly, mostly brown rust.

That's already being used. Without problems.

Our digital PBX uses 54V (which is what 48V batteries put out) at up to

150mA. We don't have any problems at all with power over 66 blocks, 110 blocks, RJ-11 or RJ-45. The telcos use 108V across the pair with T1 spans.
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