What is my buss made of?

[netphish]

We recently were able to get into and old 60's era GE Metal-enclosed switchgear to take a look a the buss configuration. We have an un-provisioned cubical that we would like to extend buss into, but we want to ensure the buss has the required current-carrying capacity for our application. The horizontal buss was all bare copper but the vertical buss was shiny silver in color. We could only see it through a small hole around the load side of the breaker but it looked much like a solid piece of extruded aluminum buss measuring 3/8 x 4". The vertical buss is supposed to be rated for 1600amps.

Question, is there a way to verify the construction of the buss so we can determine the current-carrying capacity? There were surface scratches on an edge and I didn't see copper showing through. Thanks, Chris

 

[Jraef]

We recently were able to get into and old 60's era GE Metal-enclosed switchgear to take a look a the buss configuration. We have an un-provisioned cubical that we would like to extend buss into, but we want to ensure the buss has the required current-carrying capacity for our application. The horizontal buss was all bare copper but the vertical buss was shiny silver in color. We could only see it through a small hole around the load side of the breaker but it looked much like a solid piece of extruded aluminum buss measuring 3/8 x 4". The vertical buss is supposed to be rated for 1600amps.

Question, is there a way to verify the construction of the buss so we can determine the current-carrying capacity? There were surface scratches on an edge and I didn't see copper showing through. Thanks, Chris

Depends a little bit on what you mean by "shiny". Both Aluminum and Copper bus can be tin plated or silver plated, but tin plating is a dull finish, not reflective / "shiny". Silver plating can be shiny, but silver plated aluminum bus is rare. Tin plating tends to electrically bond better with the copper so that scratching it does not necessarily expose copper coloring. GE should be able to tell you for sure though by you sending them the serial number. Finding the right place within the behemoth that is GE is however tricky. I would take the information to a GE distributor near you, let them sort through the pile of 800 numbers for you.

We use 1/4" x 4" but for 1200A, but for 1600A we use two of those stacked, so it is 1/2" x 4". Most likely though, 3/8" x 4" will work for 1600A, it all depends on what temperature rise they tested for.

Side note for your future use:
Electrical bus has one "s". "Buss" is the shortened rendition of the manufacturer of fuses, 'Bussman', which comes from a person's name. Very common mistake.

 

[brian john]

Based strictly on my expierence and the age of the gear tin plated copper

 

[templdl]

We recently were able to get into and old 60's era GE Metal-enclosed switchgear to take a look a the buss configuration. We have an un-provisioned cubical that we would like to extend buss into, but we want to ensure the buss has the required current-carrying capacity for our application. The horizontal buss was all bare copper but the vertical buss was shiny silver in color. We could only see it through a small hole around the load side of the breaker but it looked much like a solid piece of extruded aluminum buss measuring 3/8 x 4". The vertical buss is supposed to be rated for 1600amps.

Question, is there a way to verify the construction of the buss so we can determine the current-carrying capacity? There were surface scratches on an edge and I didn't see copper showing through. Thanks, Chris

I'm sure that you asked GE what the bus rating was. What was their reply?

 

[petersonra]

Where I used to work we always spec'd sliver plated copper bus in MCCs because for whatever reason it cost less from AB for our discount code.

 

[zog]

We recently were able to get into and old 60's era GE Metal-enclosed switchgear to take a look a the buss configuration. We have an un-provisioned cubical that we would like to extend buss into, but we want to ensure the buss has the required current-carrying capacity for our application. The horizontal buss was all bare copper but the vertical buss was shiny silver in color. We could only see it through a small hole around the load side of the breaker but it looked much like a solid piece of extruded aluminum buss measuring 3/8 x 4". The vertical buss is supposed to be rated for 1600amps.

Question, is there a way to verify the construction of the buss so we can determine the current-carrying capacity? There were surface scratches on an edge and I didn't see copper showing through. Thanks, Chris

There should be a nameplate on your switchgear with a summary number. Send me that (via PM) and I should be able to find out for you. We also have kits to add breakers and cell provisions to empty cells like this.

 

[Jraef]

Where I used to work we always spec'd sliver plated copper bus in MCCs because for whatever reason it cost less from AB for our discount code.

You have to be careful though, silver plating can grow "whiskers" in the presence of hydrogen sulfide in the atmosphere, which happens in WWTPs, power plants and processes that deal with sulfur, either as an ingredient or a byproduct. I learned that the hard way in the late '70s at a geothermal plant. The MCCs all had silver plating, they flashed over after about 4 years of service and we found whiskers all over everything that had silver in it or on it. On contactors, because they open and close a lot, they don't get a chance to get very long. But on bus bars and unused circuit breakers, they grew several inches in some cases and lead to flash-overs.

 

[zog]

Yep, looks like this



Tin plating is a common solution.

 

[Besoeker]

We use 1/4" x 4" but for 1200A, but for 1600A we use two of those stacked, so it is 1/2" x 4". Most likely though, 3/8" x 4" will work for 1600A, it all depends on what temperature rise they tested for.

We'd probably us 2 bars, each 50mm by 6.3mm spaced apart by the thickness of one bar.

Side note for your future use:
Electrical bus has one "s". "Buss" is the shortened rendition of the manufacturer of fuses, 'Bussman', which comes from a person's name. Very common mistake.

Side side note. It's Bussmann.
It's a common mistake. Our buyer used to make it often............

 

[Jraef]

...
Side side note. It's Bussmann.
It's a common mistake. Our buyer used to make it often............

OMG! All these years and I NEVER noticed that!

Side side side note... It's now spelled "Eaton" anyway...

 

[SG-1]

Yep, looks like this

View attachment 8238 View attachment 8239

Tin plating is a common solution.

Looks like a primary disconnect assembly that needs to shave.

 

[iceworm]

We'd probably us 2 bars, each 50mm by 6.3mm spaced apart by the thickness of one bar. ............

6.3mm - That's interesting. So they buy 1/4" material and shear it to 50mm. I'm surprised the suppliers don't just make 50.8mm x 6.3mm :slaphead:

ice

 

[ATSman]

Depends a little bit on what you mean by "shiny". Both Aluminum and Copper bus can be tin plated or silver plated, but tin plating is a dull finish, not reflective / "shiny". Silver plating can be shiny, but silver plated aluminum bus is rare. Tin plating tends to electrically bond better with the copper so that scratching it does not necessarily expose copper coloring. GE should be able to tell you for sure though by you sending them the serial number. Finding the right place within the behemoth that is GE is however tricky. I would take the information to a GE distributor near you, let them sort through the pile of 800 numbers for you.

We use 1/4" x 4" but for 1200A, but for 1600A we use two of those stacked, so it is 1/2" x 4". Most likely though, 3/8" x 4" will work for 1600A, it all depends on what temperature rise they tested for.

Side note for your future use:
Electrical bus has one "s". "Buss" is the shortened rendition of the manufacturer of fuses, 'Bussman', which comes from a person's name. Very common mistake.

For copper the rule of thumb we have always used is : 1 square inch cross sectional area = 1000A in free air.
This seems to be supported in the link:

http://www.nationalswitchboard.com/busbar.html

 

[Besoeker]

OMG! All these years and I NEVER noticed that!

Side side side note... It's now spelled "Eaton" anyway...

I think that they will continue to be marketed as the Bussmann brand just as they were when they were a Cooper product.

 

[Besoeker]

6.3mm - That's interesting. So they buy 1/4" material and shear it to 50mm.

One day you guys will appreciate the merits of going SI and catch up with the rest of the developed world...............

 

[SG-1]

One day you guys will appreciate the merits of going SI and catch up with the rest of the developed world...............

Probably the same day we go 50Hz. :happysad:

 

[Besoeker]

Probably the same day we go 50Hz. :happysad:

There are plenty of countries that are 60Hz and not using Imperial units.
But very few where Imperial is still the official system.
Myanmar and Liberia and USA.

 

[SG-1]

40 years ago I was being taught the metric system, because we were going to change over in a few years. I wonder if that is still going on in American schools ?

I was told a few weeks ago by a coworker that Eaton did not purchase the Bussmann fuse part of Cooper Power Systems.

 

[Besoeker]

40 years ago I was being taught the metric system, because we were going to change over in a few years. I wonder if that is still going on in American schools ?

I don't know. My wife, as you may know, is American so I have a few American in-laws. She doesn't think any were taught metric units at school. She likes to cook and many/most of the US ingredients she gets are dual marke.

I was told a few weeks ago by a coworker that Eaton did not purchase the Bussmann fuse part of Cooper Power Systems.

Not something I'd heard. Statements made at the time of the merger commented on a combined force of 100,000 employees, 30,000 from Cooper, 70,000 from Eaton.

A link...

http://www.eaton.com/Eaton/OurCompany/NewsEvents/NewsReleases/PCT_361382

 

[gar]

130323-1134 EDT

It may be possible using a coil excited at 1 kHz to measure the conductivity difference between a copper and aluminum bus bar. Bars of comparable cross section are required.

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