Silver plated versus tin plated copper bus
Silver plated versus tin plated copper bus
(OP)
On a 600 volt motor control centers, I have noticed that manufacturers offer both tin plated and silver plated copper bus for power bus connections. At a 1,200 amp rating, which type of connection is preferred or does it make any difference






RE: Silver plated versus tin plated copper bus
But one of the manufacturers (in the USA) indicated that silver plating is the standard offering and tin plating is added cost option. Tin plating is recommended for protection against corrosive environment. Unless the application has corrosive environment (for the copper), for all "normal" applications sivler plating is as good as any.
RE: Silver plated versus tin plated copper bus
The NEMA standards are somewhat inconsistent on this. For some categories silver-plating is standard and for others, tin-plating is standard. I can never remember which is which.
RE: Silver plated versus tin plated copper bus
I am told that this phonomenon was well known back in the 1940's and was the reason that lead was put into solder - lead suppresses the growth os the whiskers.
RE: Silver plated versus tin plated copper bus
From what I have seen Tin plating is standard for most bus unless it is a critical point, such as where a breaker or cell racks in - then silver plating is offered. From what I can remember silver plating is better than tin, not the other way around...
Silver plating is more expensive in the manufacturing process,...
Regards,
TULUM
RE: Silver plated versus tin plated copper bus
Link to photo site
Tin whiskers as well, but the available research on tin whiskering indicates that the whiskers are rarely over a few mm long, so if proper bus spacing is maintained, they don't tend to cause troubles. For this reason, many facilities engineers who know that sulpher may exist in their enviroinment, even in very low concentrations, will specify tin plating over silver.
Silver has better bus-to-bus conductivity however, so it is preferrable wherever it can be used without problems. But because of the whiskering issue, some manufacturers have started offering tin as standard and charging a premium for silver.
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Silver plated versus tin plated copper bus
It is amazing how you dig up these pictures. Definitely, this one looks scary.
I have never seen something like this. How the hell does this happen ?
RE: Silver plated versus tin plated copper bus
I had to go through an exercise in H2S "certification" two years ago and got some help in this forum (thread238-103502), which included this link to a paper by a Schneider engineer who did a study on it for NASA in 2002. 2002 Chudnovsky paper on silver whiskering. She used some of the photos taken from the site I listed above.
I had known of the phenomenon without knowing exactly what it was because of a rather catastrophic failure I was involved in at a geothermal power plant in Northern California in the mid 1980's. The company I worked for sent out some MCCs with silver bus plating, even though the spec called for tin. An upper manager rejected my original engineering package because he didn't want to have special bus bar ordered (our standard was silver plated). His reasoning was that "silver was better, so give them the silver and tell them that we won't charge them extra", thinking it was strictly an economic issue. They missed that tidbit in the submittal review. When they called us a year after the installation and said our bus bars were "hairy", we thought maybe they were inhaling the local fumes from the pot growers that were prolific in that area. By the time we got the pictures back to start investigating (no digital pics in those days of course), there was a flash-over. Very very expensive lesson for everyone.
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Silver plated versus tin plated copper bus
It must be a rare exception and an utterly ignored for maintenance and unattended installation.
tultum:
Cost of tin vs silver plating may differ depending upon location, but in the USA silver plating is cheaper than tin plating for whatever reason.
RE: Silver plated versus tin plated copper bus
You sure have lived a life of surprises (& learning) and thanks for sharing it.
I have learnt in the past days that you never stop learning.
(2004 ??? Man, how could you remember that far ? Me, I live day to day.)
RE: Silver plated versus tin plated copper bus
RE: Silver plated versus tin plated copper bus
RE: Silver plated versus tin plated copper bus
RE: Silver plated versus tin plated copper bus
RE: Silver plated versus tin plated copper bus
edison123,
Until my most recent stint of 11 years in one place, I had a resume that practically needed a forklift to move it from place to place. I can't remember names to save my soul, but being a "kinetic learner", I remember experiences with (sometimes annoying) clarity.
My wife calls me "a fountain of useless information".
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Silver plated versus tin plated copper bus
RE: Silver plated versus tin plated copper bus
Some day I have to find my photo essay on that and publish it here. It was from the pre-digital camera days so I need to dig up the photos and scan them, but I can't find the envelope that I put them in.
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Silver plated versus tin plated copper bus
Burndy has a basic writeup on making electrical connnection at: ht
In a nutshell:
Unless the copper is badly oxidized, good
contact can be obtained with very little or no
cleaning.
Silver oxide is even more easily broken down
by the contact pressure;
On the other hand, aluminum oxide is a hard,
tenacious, high resistance film that forms
very rapidly on the surface of aluminum
exposed to air. The article also talks about the advantages and disadvantages of plating aluminum.
RE: Silver plated versus tin plated copper bus
htt