ECN Forum
Posted By: rwilsond NEC, SCCR, and UL - 07/07/07 06:48 AM
Section 440.4(B) of the 2005 NEC requires that the Short Circuit Current Rating (SCCR) be included on a visible nameplate for "Hermetic Refrigerant Equipment" having multiple motors or combination loads, when supplied by an OCPD of more than 60A .

A major industrial HVAC equipment manufacturer states that their equipment is excluded from this requirement (even in states that have adopted the 2005 NEC) because it is "Listed" per UL 1995 and that is the only thing that they must comply with. They state that this NEC requirement only applies to equipment that is "built up" in the field.


Is the manufacturer's position correct?


(FYI: although this UL standard requires that some basic electrical information be included on the nameplate, it does not require that the SCCR be determined, nor does it require that the SCCR be provided on any nameplates).
Posted By: JBD Re: NEC, SCCR, and UL - 07/07/07 03:10 PM
No.
Only the local AHJ can decide if a piece of equipment can be installed in their jurisdiction. A "listing" is only a tool for the AHJ to use in their evaluation of the equipment. Very few, if any, state and local codes require the AHJ to automatically accept all "listed" equipment.
Posted By: gfretwell Re: NEC, SCCR, and UL - 07/07/07 11:33 PM
My guess is in these big machines a lot of this stuff depends on things in an external starter.
Posted By: iwire Re: NEC, SCCR, and UL - 07/08/07 04:04 PM
Originally Posted by JBD
Very few, if any, state and local codes require the AHJ to automatically accept all "listed" equipment.


Happy to say I live in one of those few places. smile


Quote
90.4. Revise the first paragraph to read as follows:
90.4 Enforcement. This Code shall be used by the
authority enforcing the Code and exercising legal
jurisdiction over electrical installations. The authority
having jurisdiction of enforcement of the Code
shall accept listed and labeled equipment or materials
where used or installed in accordance with instructions
included with the listing or labeling.
The
authority shall have the responsibility for deciding
upon the approval of unlisted or unlabeled equipment
and materials, and for granting the special
permission contemplated in a number of the rules.

Posted By: renosteinke Re: NEC, SCCR, and UL - 07/08/07 04:55 PM
UL is not about to list something that does not comply with the NEC. If the nameplate is missing something, there has to be a reason.

"Listing" can get a bit confusing. You have to be certain you understand just what the UL tag means. Your best bet is to look at the UL "White Book," and call UL if you still have questions.

It is possible that there are different listings for components, partial assemblies, items shipped complete, and items that need field assembly. A listing might apply only when all components are there - and not to, say, the compressor alone.


Another possibility .... IS there a UL label? Or, is the HVAC maker simply claiming that his equipment meets the standard? Since UL is an "ISO 9000" firm, anyone can claim to test to their standards. That's not the same, however, as actually having a UL listing. No label, no listing. It does not matter what the package, literature, or catalog says. Look for the label!
Posted By: Retired_Helper Re: NEC, SCCR, and UL - 07/08/07 05:57 PM
Originally Posted by renosteinke
Another possibility .... IS there a UL label? Or, is the HVAC maker simply claiming that his equipment meets the standard? Since UL is an "ISO 9000" firm, anyone can claim to test to their standards. That's not the same, however, as actually having a UL listing. No label, no listing. It does not matter what the package, literature, or catalog says. Look for the label!


And don't get carried away with ISO 9000. This standard has to do with a company's internal procedures, and the documentation of those procedures. It represents some kind of guarantee that you're dealing with an organized and professional outfit. One company's ISO 9000 can easily bear no relation to another's except possibly similar formats.

I was always convinced that ISO 9000 was a European gimmick, that Euro manufacturers hoped snobbish Americans would scorn, thus keeping them out of Euro markets. If so, they underestimated Yank enthusiasm for such things. In this case, it just happened that the ISO 9000 fad actually had some good results. When you document properly, you have first class training materials. When you update properly, you have a document trail that answers the question of what changed when.
Posted By: renosteinke Re: NEC, SCCR, and UL - 07/09/07 12:47 AM
Actually, Retired Helper ... there was quite a debate within UL as to whether to get the ISO certification. One of the arguments 'against' was that doing so would put them on the same plane as any other "ISO" testing lab .... meaning that there was an opening for competitors to spring up.

And, that is exactly what has happened. Today there are myriad places testing "to" various UL standards. Assuming the other place also has ISO certification, then the AHJ has no choice but to accept it.

I am aware that the basic language of the ISO rule is deceptively simple. Keep in mind that this whole ISO thing was kicked off by the desire of major manufacturers to "open up" their supply chain to new sources. The sundry ISO audits and documentation exist to reassure the final customer that all the requirements were met.
Posted By: gfretwell Re: NEC, SCCR, and UL - 07/09/07 05:14 AM
I was the ISO 9000 coordinator at IBM Ft Myers. My thought is the whole "process" was designed to make it easier to consolidate jobs when they laid people off.
It was not a productivity tool, nor was it a quality assurance tool but it certainly made it easier to turn jobs skills and responsibilities into a well defined commodity.
Posted By: rwilsond Re: NEC, SCCR, and UL - 07/09/07 06:13 AM
Quote
The authority having jurisdiction of enforcement of the Code shall accept listed and labeled equipment or materials where used or installed in accordance with instructions included with the listing or labeling.

Bob ("iwire"): Thanks for the input. That quote (I assume excerpted from the Massachusetts Electrical Code) is very interesting - I was not aware that any AHJ was ever mandated to accept anything. So I wonder how an AHJ in that state is expected to address an issue like this?

On one hand the AHJ must verify that the NEC's requirement for the SCCR to be posted on the equipment is satisfied, and on the other hand, he is required to accept it as-is. What if he knows that this equipment will be fed from a massive transformer sitting a few feet away, capable of feeding 50,000A to a fault within the equipment? Does he simply HOPE that the equipment is capable of withstanding a 50kA fault (but wisely put sufficient distance between it and himself before it is energized - just in case)?

In the case I originally posted, the equipment will have a UL Listing Label, however this label will not have an SCCR on it. The 2005 NEC requires that the SCCR be placed on "A visible nameplate". But note that the NEC does not even require that this equipment be Listed; thus it has been argued that it might not necessarily be the UL (or whatever NRTL) that has the responsibility to determine the SCCR and to provide it on a nameplate. But it seems that the manufacturer or supplier of the equipment certainly would have the responsibility to determine the SCCR somehow and to get it on A nameplate (not necessarily the Listing nameplate).

In other words it would follow that the NRTL would have no responsibility for what SCCR was placed on the equipment since they never involved themselves with it in the first place; which seems to me to defeat the whole point of getting an independent & qualified lab to ensure that the equipment is safe and that sufficient information will be provided (e.g., a credible SCCR on a nameplate) so that the power system designers and installers can know that they are providing a safe installation.

Fyi, I called the UL department responsible for UL 1995 ("Heating and Cooling Equipment") and the guy said that it is indeed possible that the NEC has requirements that are beyond the applicable UL standard's scope - and for this particular case, it may be something that needs to be added to UL 1995 (I then sent a formal request to them to add this requirement, to be consistent with the 2005 NEC).
Posted By: Retired_Helper Re: NEC, SCCR, and UL - 07/09/07 01:51 PM
Originally Posted by gfretwell
I was the ISO 9000 coordinator at IBM Ft Myers. My thought is the whole "process" was designed to make it easier to consolidate jobs when they laid people off.
It was not a productivity tool, nor was it a quality assurance tool but it certainly made it easier to turn jobs skills and responsibilities into a well defined commodity.


frown Greg has identified the downside of any manufacturing improvement system. Companies that gave away the store during the 50's and 60's began looking for any excuse to cut earnings and eliminate workers in the 70's and 80's (not that they've stopped yet).
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