Busbar SCCR Reference

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bwat

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Does anybody have a reference/standard that could be used to create busbar systems with a certain SCCR? Let's say 25kA or 35kA?

I'm hoping there might be an IEEE standard, or some publication from a manufacturer that is held as a standard that I can use and reference. I'm hoping "spend $$$ on testing" isn't the only answer.

I may have a situation where I have some components, such as fuses and others, that require a simple, yet custom, busbar solution for mounting. It's not a UL508A panel, but if I were to use UL508A as reference, it defaults unknown busbar to 10kA, and that is probably going to be a little low for my application.
 
bwat said:
Does anybody have a reference/standard that could be used to create busbar systems with a certain SCCR? Let's say 25kA or 35kA?

I'm hoping there might be an IEEE standard, or some publication from a manufacturer that is held as a standard that I can use and reference. I'm hoping "spend $$$ on testing" isn't the only answer.

I may have a situation where I have some components, such as fuses and others, that require a simple, yet custom, busbar solution for mounting. It's not a UL508A panel, but if I were to use UL508A as reference, it defaults unknown busbar to 10kA, and that is probably going to be a little low for my application.
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You should take a look at the latest UL508A standard. It has an interesting appendix on bus bars.
 
bwat said:
Does anybody have a reference/standard that could be used to create busbar systems with a certain SCCR? Let's say 25kA or 35kA?

I'm hoping there might be an IEEE standard, or some publication from a manufacturer that is held as a standard that I can use and reference. I'm hoping "spend $$$ on testing" isn't the only answer.

I may have a situation where I have some components, such as fuses and others, that require a simple, yet custom, busbar solution for mounting. It's not a UL508A panel, but if I were to use UL508A as reference, it defaults unknown busbar to 10kA, and that is probably going to be a little low for my application.
Click to expand...

There might be some standard out there for how to calculate the mechanical forces and provide guidance for bracing design, but in the end I believe it will come down to testing. X/R ratios will vary for every application and equipment generally has a test X/R to compare against directly or indirectly by use of multiplying factors. Is there a particular UL standard your bus bars fall into?

If anyone knows of any standards that addresses the OP, I would also like to know.
 
There are UL listed bus assemblies that you can use in custom control panels, which is what I think Bob Petersen is referring to (I don't have the latest UL508A now). But what I have heard about the new UL508A appendix is that you must EITHER use a pre-listed busbar SYSTEM as is now sold by many of the enclosure mfrs and a few of the control mfrs., or if you want to assemble you own from scratch you must preform a Short Circuit test and they now give you the requirements for how it is to be assembled and tested. Unless you are planning on doing a high volume of the same panels, you might find the testing costs a bit prohibitive compared to using a pre-listed system.
 
Jraef said:
There are UL listed bus assemblies that you can use in custom control panels, which is what I think Bob Petersen is referring to (I don't have the latest UL508A now). But what I have heard about the new UL508A appendix is that you must EITHER use a pre-listed busbar SYSTEM as is now sold by many of the enclosure mfrs and a few of the control mfrs., or if you want to assemble you own from scratch you must preform a Short Circuit test and they now give you the requirements for how it is to be assembled and tested. Unless you are planning on doing a high volume of the same panels, you might find the testing costs a bit prohibitive compared to using a pre-listed system.
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Appendix D – Maximum 100 000 Ampere Short-Circuit Current Rating Without Short-Circuit Test
D1 Scope
D1.1 These requirements cover stand alone busbar assemblies having an rms symmetrical short-circuit
current rating for which short-circuit tests may be waived. These requirements do not otherwise amend the
requirements in this standard.
 
So isn't that saying you can use a system that ALREADY has a short circuit current rating without having to test it again, so long as you don't need over 100kA?
 
Jraef said:
So isn't that saying you can use a system that ALREADY has a short circuit current rating without having to test it again, so long as you don't need over 100kA?
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No. It is pretty clear it means as long as you follow the construction standards in the appendix you can diy.

Personally, I think it is usually more cost effective to buy something. Bus bar systems are not real expensive, however, many have sccr limitations that can be problematic.
 
Ah, I just read the note someone sent me on that again and it said NEITHER, not EITHER, on the issue of requiring listing or the SC testing so long as you follow their procedures. I read that wrong.
Thanks.
 
I'm at a loss bwat, are you trying to build a transformer bus bar/system?

It seems like that would be an expensive undertaking, or are you trying to figure out where to locate these components for a lower sccr?

What is the existing AFC?

UL listed bus assemblies that you can use in custom control panels ,<-- can you tell me where I would find that Jraef.
 
petersonra said:
You should take a look at the latest UL508A standard. It has an interesting appendix on bus bars.
Click to expand...
petersonra said:
Appendix D – Maximum 100 000 Ampere Short-Circuit Current Rating Without Short-Circuit Test
D1 Scope
D1.1 These requirements cover stand alone busbar assemblies having an rms symmetrical short-circuit
current rating for which short-circuit tests may be waived. These requirements do not otherwise amend the
requirements in this standard.
Click to expand...
Fascinating! Thanks. Even if it doesn't apply for whatever reason, that is very good information that the latest UL standard has this. I probably should have know this as I am one of our UL MTRs :oops:...
 
ElectEng said:
I'm at a loss bwat, are you trying to build a transformer bus bar/system?

It seems like that would be an expensive undertaking, or are you trying to figure out where to locate these components for a lower sccr?

What is the existing AFC?
Click to expand...

There are components that I'm trying to use, such as fuses, in a large custom drive cabinet that don't have applicable fuse holders believe it or not. You must use them with a busbar system for mounting. The power study is potentially showing SCCA of maybe 10-15kA, depending on a few factors that are not yet decided. So I wanted to go well above that.
 
bwat said:
There are components that I'm trying to use, such as fuses, in a large custom drive cabinet that don't have applicable fuse holders believe it or not. You must use them with a busbar system for mounting. The power study is potentially showing SCCA of maybe 10-15kA, depending on a few factors that are not yet decided. So I wanted to go well above that.
Click to expand...
I can't say I have ever run across fuses that did not have some kind of fuse holder available.

Are these fuses UL listed, or are they one of those awful IEC semiconductor fuses?
 
petersonra said:
I can't say I have ever run across fuses that did not have some kind of fuse holder available.

Are these fuses UL listed, or are they one of those awful IEC semiconductor fuses?
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Same before this one. You guessed correctly. They are the UR (recognized) semiconductor fuses.
 
petersonra said:
Merson has some fuse holders that you might be able to use. They just have a stud for the hole in the fuse.
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Thanks, I just looked and it looks like they only go up to 1000A. Had you happen to see any others that would work for 1100 or 1200A? It's one of those double-gang semiconductor fuses as well.
 
I reached out to Mersen to ask. No such luck. They stated "We do not have a holder for these fuses. This type of fuse arrangement is typically installed with hardware and directly tapped onto busbar."
 
petersonra said:
...
Hoffman sells some too. I think they just resell someone elses bus bars though.
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Wohner is what they brand-label, in fact I don't even think they brand it as Hoffman, they still call it Wohner. It's pretty nice stuff.
www.automation.com

Hoffman introduces 60-mm busbar system

The 60-mm Busbar System is UL508, CSA and CE recognized and safely distributes power throughout a panel while conserving panel space.
www.automation.com www.automation.com
 
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