Wire Plating...? Applications.

copper and tin are miscible. A thin layer of tin over copper is gradually penetrated by copper atoms that diffuse through it. They will corrode with the air and CO2 therein. The same happens with gold plating over copper.

Obviously if you plate either the tin or the gold as a thick layer it will take longer for this to take place. Tin costs a little more than copper, but thick plating is an option.

Gold costs a lot more than copper, so thick gold becomes a lot more expensive.

So what to do? Now nickel is not miscible with copper or tin, so if you plate a very thin layer of nickel over the copper you can then plate a thin layer of tin or gold, since the copper will not diffuse into either the tin or the gold.

You can use the wire with only nickel plate, but it is not solderable as the solder will not wet it very well, unless you use an aggressive flux which will act on the nickel.

I would suggest you use copper wire with a thin nickel plate followed by the tin or gold you are going to use the the correct thickness.

Addressing your application:

While Ni plated Cu wire is an excellent conductor of electricity, you could use a fine stainless-steel wire to make your braid. Type 304 stainless is an excellent weather resistant material, for instance, and has a greater resistance to metal fatigue should your strap undergo considerable flexure. 316 is an excellent stainless steel, as well, although it may suffer more from metal fatigue if continually flexed.

Broad, raw-copper straps are sometimes used to connect a grounding network to tower lightning systems. This makes more sense than using wire or braid as a lightning stroke contains a great deal of high-frequency AC components subject to skin effect. The more surface area of the braid/strap, the lower the AC electrical resistance per unit cross-section. These straps are not plated at all, yet they do their jobs extremely well.

-e

wow, thank you very much for the informative responses :)

Here is a company that is in the wire biz... some references to what is used for what type of wire. Bekaert Wire I have used their wire for braided metal applications in the past.

Additional information on grounding methods and practices can be found here. This site is primarily concerned with lightning protection, if that is your application. If not, many of the same methods and practices still apply.

-e

e and aurizon,

Any references to your info? Some more info on my application, the grounding strap needs to be rated for 100 amps, outdoor use, it will be flexed on a regular basis, hence i was leaning towards a flat copper braid. Length is roughly 2 feet, possibly heat shrink wrapping it to insulate it, the end terminations will be lugs crimped on.

See if this outfit might have what you need. If your ground strap will undergo a great deal of flexure, you'll need to relieve stress at the points where the strap meets the lugs.

If the strap connects two objects across a hinge, a way to distribute the stress over the length of the strap is by shaping it into an open, loosely-wound helix of just a few turns. Here the axis of the helix should be parallel to the hinge axis. If possible, mount the helix as a flat coil (again, only a few turns) at the end of the hinge with its axis co-linear with the hinge axis.

If the strap will be moving freely - like a power cord might - be sure to strain-relieve the points where it meets the lugs. A heavy-gauge, tightly fitted length of heat-shrink tubing over both the braid and the lug at each point will go far in protecting the braid from fatigue at these locations. I would do this regardless.

Unless the braid will be subject to abrasion, I wouldn't bother enclosing its entire length with shrink tubing as this will trap moisture and other nastiness inside the braid.

Good luck!

-e

Also take a look at this outfit. This one may have exactly what you need in any flavor you like.

-e

-e...you are the man! with the groundstraps.com... so simple yet such a site

the other site amgndsys is also a great site ive been working off of too.

I'd opt for a 200-amp strap - or at least a 150-amp beastie - unless you've already supersized your spec to accommodate The Future (it comes soon enough), the Inevitable Contingency, or The Ultimate Short.

-e