Copper washers

[belfert]

Where does one buy copper washers?  I assume these are not a hardware store item based on Sean's article.  McMaster-Carr only has them down to #10 and I might need some #8 ones.

I have to admit before I read Sean's article I didn't know it was a no-no to use steel washers for electrical connections.  I know I've replaced lost washers on electrical connections with steel ones.

[luvrbus]

Belfert, www.electerm.com they have everything for the battery hook up or www.sunwind.com both have the washers,there are coated nuts and washers on the market that work also



good luck

[Sean]

Available from Amazon and many others.  Try this link:

http://www.google.com/products/catalog?q=copper+washers&cid=7024368436478320264&ei=6MfrTPfaNYW8lQfHrMhr&sa=X&oi=product_catalog_result&ct=result&resnum=1&ved=0CCIQ8wIwAA#

Good to know at least one person reads my column!

-Sean
http://OurOdyssey.BlogSpot.com

[Sean]

Sorry, just realized that assortment only goes down to 1/4".

Copper washers are commonly available down to 3/16" (#10) or 6mm.  Smaller than that you might need to use brass, which are available in 5/32" (#8).

That said, when you get down to those sizes, the issues I raised in the article are less meaningful.  That's because you can't carry much current on a #8 terminal in the first place.  What I suggest when you have a screw or terminal post this small is that you make certain all the terminal lugs are making direct contact with one another, then use steel fasteners to compress them.  IOTW, so long as there are no washers intervening between current-carrying lugs, it is OK to use other materials to simply apply the correct amount of mechanical pressure.

-Sean
http://OurOdyssey.BlogSpot.com

[cody]

Except for a short time during WW2 when copper was discontinued in pennies due to war time shortages, they were still mostly copper until 1982, 95% copper is still pretty close to all copper, the clad pennies came out in 1982 and that year both the 95% copper pennies were still produced as well as the new clad pennies. It is true that the 100% copper pennies were discontinued in 1857, in 1864 the new formulation for pennies was 95% copper and 5% tin.

[boogiethecat]

Personally I don't like to use copper washers because they are soft and kinda squishy (hard to get properly tight) and they have a simlar problem to steel- they tend to oxidize like crazy.
It's completely OK to use brass washers on electrical connections, as well as stainless steel.  Stainless isn't as good a conductor but for 99% of the applications you'd give them, they'd be fine.
Steel is out simply because it corrodes...
Maybe that'll give you some more options.  I use SS on everything and zero problems...

[bevans6]

I find this very interesting.  Not having read the article, I did some internet searches on the subject and indeed it appears that plated steel washers aren't recommended for current carrying connections.  They apparently are not corrosion protected enough for reliability.  I have been using AN960 washers (plated with Cad II, whatever that is) to spread the load under the nut over the connector, but I guess I will have to try to find something else.  I can get stainless easy  enough.  I  keep some copper and aluminium on hand but only use them when I need a sealing washer, they squish out too easily and don't keep preload worth a darn.  I was interested to see the use of Belleville washers in stainless to maintain preload in bolted electrical connections.

Brian

[belfert]

The problem with stainless and steel washers according to Sean's column is the resistance of the metal.  My main need for washers would be for my Vanner.  I lost some of them and replaced them with steel not knowing better.  My Vanner studs are larger than #8 for sure.

[luvrbus]

What are the side mounted battery bolts made from I never saw one made of brass or copper only coated steel,Cat always had a coated steel nut washer combined for their equipment batteries at least mine did this is not clear to me I guess I missing something but the LifeLine AGM batteries studs are S/S and use S/S combined washer and nut, some stud batteries also come with coated steel nuts that I have bought ?


good luck

[kyle4501]

If I'm thinking about the same connections, the primary purpose of the steel hardware is for clamping the conductors together, not carrying current.

I know the side lugs on the battery in my Suburban aren't the best at maintaining conductivity . . . . I have to re-tighten then often. 

[eddiepotts]

The article said you could use any washer between the nut and the connection just not between the connections.

If the ring or spade terminals are in
direct contact with one another and with any device the
threaded terminal is part of, then a steel washer can be
at the very top of the stack, just below the nut, to hold
the stack together.

On side terminals on a battery the connection is lead on lead the bolt runs through the middle. I think the lead threads in the battery give some over time that's why they need to be re-tighten once in a while.

[HighTechRedneck]

Added:  Oops, should have reread OP.  Looking for smaller than this.  Oh well, another source for the other sizes.
Harbor Freight to the rescue:

http://www.harborfreight.com/110-piece-copper-washer-assortment-67526.html

■Sizes: 1/4" (30 pieces), 5/16" (25 pcs.), 3/8" (20 pcs.), 7/16" (15 pcs.), 1/2" (10 pcs.), 5/8" (10 pcs.)

[Ed Hackenbruch]

And just to add to what Cody was saying about steel pennies being produced in WW2 instead of copper ones.  In 1943 less than 20 were accidentally struck in bronze at the Philadelphia and San Francisco mints, with only one known to have been struck at the Denver mint. That one was just sold at auction for $1.7 million. Might keep that in mind the next time you see a penny on the ground and don't want to bother picking it up.

[gus]

It doesn't really matter what you use because most connections are dissimilar metals anyway, you just have to keep an eye out for corrosion.

Most stud connections are between the wire eye and the stud shoulder, not the washer and nut. The nut is to hold it secure and the washer is to keep the nut from destroying the wire eye. Since the current flow is not through the washers I see no reason not to use cad plated washers, at least the cad will sacrifice before it rusts.

My 4104 has steel studs, nuts and washers throughout. Of course they rusted but after 56 years what wouldn't?

Battery connections are the steel stud, a copper or brass cable eye and a steel nut. Or a lead post, a lead cable clamp to a copper cable and a steel bolt. Interestingly the two lead connections are very bad to corrode. After a few months, no more than a year, the battery post will turn black. It looks OK but is a black, thick coat of corrosion that needs to be scraped off.

This is a big fuss over a small problem.

[Sean]

Apparently there is a great deal of confusion here over what I wrote in the column, and perhaps there was some lack of clarity on my part there.  So let me clear some things up.

I should point out here that this subject came up in regards to a terminal post on a high-current solenoid.  As Gus writes, the electrical connection is properly between the lug (what he calls a "wire eye") and the terminal shoulder.  I can assure you, BTW, that the conducting part of the terminal on high-current devices like switches and solenoids are copper or brass, and not steel.  (Likewise, the conducting parts of battery terminals are lead and not steel.)

While the manufacturer intends for the lug(s) to be the first item on the stud, followed by a washer and nut whose sole function is to securely hold the actual conducting lug(s) to the terminal mechanically, what I was trying to get at in the column is that I have, in fact, seen installations where washers have been inserted between the lug and the conducting part of the terminal.  There are sometimes good reasons for this, such as having a lug that simply will not sit square (flat) on the terminal without some shimming, or to raise a larger lug above a casting protrusion on the solenoid casing.

In the case of a connecting terminal (as opposed to a device terminal), such as those found on terminal strips and connecting posts, the stud, nut, and washers are again there simply to provide mechanical force to hold the actual conducting surfaces of the lugs together.  The electrical connection is lug-to-lug, and not through the threaded post.  However, here again I have seen washers intervene between the conductive lugs.  Again there are sometimes good reasons for this, for example because the orientation of two lugs is such that their wire crimps will interfere with one another without washers in between.  "Flag lugs" are famous for this, especially if the wires end up on the same side, and I have seen as many as three washers inserted between a pair of lugs to get them to sit square.

When washers intervene in this way between the conductive surfaces of the lugs, or between a lug and the terminal shoulder in the case of a device terminal, you want to use the most conductive washers available.  Copper is the best choice but brass or bronze are also acceptable.  Brass, however, has the additional problem of galvanic issues associated with the zinc content and therefore is not recommended in wet locations and particularly around battery boxes where small amounts of leaked electrolyte can exacerbate this problem.  By contrast, steel is a poor choice, and stainless steel in particular is an extremely bad choice.  I have seen stainless washers in 200-amp applications become literally too hot to touch.

As I wrote in the article, washers located immediately below the nut and above the conductive parts of the assembly are not part of the current path and can be any suitable material; plated steel is common and stainless is also common in marine applications.  But be sure you know who is working on your system, because an ill-informed technician working on such a terminal post can easily interchange what was supposed to be the top, mechanical-only washer with a current-carrying washer lower in the stack, and I have seen the results of this more than once.  For this reason I try to avoid having multiple washer types in the same assembly.

As I indicated earlier in this thread, these problems are much more exaggerated in high-current applications such as alternator, starter, and battery connections as well as bridging solenoids, inverter terminals, and main fuses.  Regarding this last item I have seen more than one 400-amp class-T fuse separated from the conductors on one or both sides by stainless washers, and this is certainly one place where you really want the lug and the fuse to be in direct contact with one another, with the washers outboard of the connection.

I know there will be those who will say that they have used steel washers for years with no apparent ill effects, and while that may be true, the fact is that those steel washers have been stealing (pardon the pun) power from your systems, turning it into waste heat.  While it is extremely unlikely that any connection on a bus conversion can become an actual safety hazard through the use of poorly conductive washers, why leave any of your precious battery power on the table?

Hope that clears up the confusion.

-Sean
http://OurOdyssey.BlogSpot.com