Panel Board Bus Material (Hard-drawn copper, 98 percent conductivity)

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DPMin

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The panel board bus material for a project I am working on was specified as "Hard-drawn copper, 98 percent conductivity". I've done a lot of searching but I can't find any information about what this actually means. The manufacturer lists the following options for their bus material:

Temp rated Al. Tin-Plated
750A/sq. in. Al. Tin-Plated
Temp rated Cu. Tin-Plated
Temp rated Cu. Silver-Plated
Temp rated Cu. Tin-Plated
1000A/sq. in. Cu. Tin-Plated
1000A/sq. in. Cu. Silver-Plated

I haven't found any information that lets me match the specification to the available options. Can anyone shed some light on this? (and may be a link to some reading material on the topic?)

Thanks!
 
you might try someone like NSRW or some other manufacture of copper welding electrodes and bars. They have many different grades of copper. we buy copper bar stock from them for making our welding electrodes

I think it is www.nsrw.com


Travis
 
I usually just spec. copper or aluminum and leave it at that.

Is there something about the project that makes you think the buss material needs to be special??
 
steve066 said:
I usually just spec. copper or aluminum and leave it at that.

Is there something about the project that makes you think the buss material needs to be special??
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No, nothing at all, just trying to follow the spec. It's an addition to a commercial building with basic lighting and HVAC, and that's about it. The engineer included the "Hard-drawn copper, 98 percent conductivity" line as part of 500 pages of generic specs I assume he sends out with every project. I've seen it specified before but I have yet to come across anyone who knows what it means.
 
DPMin said:
No, nothing at all, just trying to follow the spec. It's an addition to a commercial building with basic lighting and HVAC, and that's about it. The engineer included the "Hard-drawn copper, 98 percent conductivity" line as part of 500 pages of generic specs I assume he sends out with every project. I've seen it specified before but I have yet to come across anyone who knows what it means.
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now you know what it means (if you followed the link).
 
petersonra said:
now you know what it means (if you followed the link).
Click to expand...

I did read your link, thanks for posting it. If I understand the article correctly, it's describing how to determine the conductivity of a copper sample in a laboratory type setting. While that's interesting, in practical terms, I'm not sure how to translate that information in a way that helps me select a bus material from the manufacturer's list of options.

I guess a better question would be: If you're an engineer have you specified a panel board bus to be "Hard-drawn copper, 98 percent conductivity"? And if so what did you intend? Just a copper bus? Do all manufactures by default supply copper bus that has 98 percent conductivity?

In other words, why not just specify "copper bus" and be done with it?
 
DPMin said:
I did read your link, thanks for posting it. If I understand the article correctly, it's describing how to determine the conductivity of a copper sample in a laboratory type setting. While that's interesting, in practical terms, I'm not sure how to translate that information in a way that helps me select a bus material from the manufacturer's list of options.

I guess a better question would be: If you're an engineer have you specified a panel board bus to be "Hard-drawn copper, 98 percent conductivity"? And if so what did you intend? Just a copper bus? Do all manufactures by default supply copper bus that has 98 percent conductivity?

In other words, why not just specify "copper bus" and be done with it?
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I would not specify something that way. In fact, I used to routinely spec silver or silver plated bus in MCCs. Now, I spec the cheapest.
 
DPMin said:
I did read your link, thanks for posting it. If I understand the article correctly, it's describing how to determine the conductivity of a copper sample in a laboratory type setting. While that's interesting, in practical terms, I'm not sure how to translate that information in a way that helps me select a bus material from the manufacturer's list of options.

I guess a better question would be: If you're an engineer have you specified a panel board bus to be "Hard-drawn copper, 98 percent conductivity"? And if so what did you intend? Just a copper bus? Do all manufactures by default supply copper bus that has 98 percent conductivity?

In other words, why not just specify "copper bus" and be done with it?
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The "Hard-drawn copper, 98 percent conductivity" is a standard "option" in MasterSpec... my guess is that's how it got included in the spec in those specific words. I'd also guess the engineer's intent was just looking for a copper bus as opposed to aluminum bussing.
 
ron said:
From http://www.geindustrial.com/Newsletter/Aluminum_vs_Copper.pdf

"The copper used in electrical equipment is nominally pure 98% conductivity commercially hard based on the International Annealed Copper Standard (IACS). "

You could likely choose the chaeper of the following Temp rated Cu. Tin-Plated or Temp rated Cu. Silver-Plated

The 1000A/sq. in. Cu. will definetly be more expensive.
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Awesome. That's good enough documentation for me. Thanks!

Shoe said:
The "Hard-drawn copper, 98 percent conductivity" is a standard "option" in MasterSpec... my guess is that's how it got included in the spec in those specific words. I'd also guess the engineer's intent was just looking for a copper bus as opposed to aluminum bussing.
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Ah yes, its all making sense now. I figured I was reading too much into the wording, but I don't particularly like making assumptions about the intent of specs. Thanks for clearing this up for me guys!
 
Shoe said:
The "Hard-drawn copper, 98 percent conductivity" is a standard "option" in MasterSpec... my guess is that's how it got included in the spec in those specific words. I'd also guess the engineer's intent was just looking for a copper bus as opposed to aluminum bussing.
Click to expand...
Yep. ALL copper bussing used in North America for equipment built to UL / NEMA specifications will be "Hard-drawn copper, 98 percent conductivity". Generally what this is put into specifications for is to avoid having someone fabricate their own bus system from off-the-shelf soft copper that you would use for making something like jewelry, art pieces or gutters.

Don't laugh I've seen it done, but only on custom CB panels for the marine industry. I guess people don't care if you get an electrical fire at sea... :slaphead:
 
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