UL 1995, SCCR, and the NEC

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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).
 

petersonra

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engineer
rwilsond said:
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).

Note the difference in wording between successive paragraphs.

440.4(A) ...shall be marked by the equipment manufacturer...

440.4(B) ...shall be provided with a visible nameplate marked...

It could be argued that by the language of paragraph 440.4(B), while the nameplate has to be provided, it does not have to be provided by the manufacturer. The "built up in the field" argument seems specious to me.
 
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Richard Bauer

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UL 1995 vs NEC 440.4 (B)

UL 1995 vs NEC 440.4 (B)

Working on a project with an air cooled condensing unit that needs to be in compliance with NEC 440.4 (B). I contacted the local electrical inspector to see what his position would be if the equipment came without the SCCR on the nameplate. His reponse was that he would find the installation in violation. Of 4 manufactures that are being considered for bid, one said that thier equipment was rated at 10,000 amps but this was not on nameplate, one said they complied only with UL 1995, and two have not responded.

I have two problems. First, the system short circuit available where the equipment will be installed is 35,000 amps at 208 volts. The second is that the equipment will not be labeled as required. To solve my first problem, one source said to install current limiting fuses ahead of the equipment using the chart in UL 508a supplement B. I am not sure if this is the correct approach. For the second problem I am assuming that a certified letter from the manufacturer may be acceptable.

My question is how are others handling this type of application problem. Thank you.
 
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