Type 1 Enclosures and listing

[SceneryDriver]

The phrase "Type 1 enclosures don't have to be listed" gets tossed around here from time to time. I've even said it. I'm now in a position where I have to defend that statement chapter-and-verse. I don't find anything in 314.40 (314, Part III) other than construction specifications relating to material thickness, etc... Is this a case of, "code doesn't tell us we can't, so we can?"



Thanks,

SceneryDriver

 

[xformer]

IMHO.... That is an AHJ issue.

 

[EC Dan]

IMHO.... That is an AHJ issue.

I'd agree with that. We know that 'approved' enclosures must be used, and approval is granted by the AHJ. It's simply more readily given for listed enclosures. We also know an enclosure shall be marked with its type rating, but I don't know if a type rating is only granted by a NRTL or if it's declarative like NEMA ratings. Certainly type 1 has requirements, such as protection against live parts. It's not a default rating.

 

[Jraef]

NEMA enclosure ratings were taken over by UL a number of years ago.

So are you an equipment mfr or a contractor putting something together in the field? The concept of "Type 1 enclosures don't have to be listed" is possibly applicable to an EQUIPMENT MFR who will be seeking an overall listing of the assembly, in which case if they are not going to claim more than Type 1 protection on some piece of custom sheet metal for their electrical system, the NRTL evaluating the assembly may accept it without a separate listing of the enclosure. That happens all the time. But in the FIELD, if the assembly is not listed as a whole, an AHJ is likely to want to see that an enclosure is listed for the intended use. I have seen that go both ways; some AHJs have rejected custom sheet metal for not having a listing. When I had a UL panel shop, we would occasionally get panels brought to us because the AHJ had rejected the custom box and we had to build it into a new listed box for them. But on others have seen the AHJ let it slide if Type 1 was an appropriate application.

 

[SceneryDriver]

NEMA enclosure ratings were taken over by UL a number of years ago.

So are you an equipment mfr or a contractor putting something together in the field? The concept of "Type 1 enclosures don't have to be listed" is possibly applicable to an EQUIPMENT MFR who will be seeking an overall listing of the assembly, in which case if they are not going to claim more than Type 1 protection on some piece of custom sheet metal for their electrical system, the NRTL evaluating the assembly may accept it without a separate listing of the enclosure. That happens all the time. But in the FIELD, if the assembly is not listed as a whole, an AHJ is likely to want to see that an enclosure is listed for the intended use. I have seen that go both ways; some AHJs have rejected custom sheet metal for not having a listing. When I had a UL panel shop, we would occasionally get panels brought to us because the AHJ had rejected the custom box and we had to build it into a new listed box for them. But on others have seen the AHJ let it slide if Type 1 was an appropriate application.

In this case, we're the contractor. We have a CNC laser and press brake in-house, and we fold up our own control enclosures and (where useful) pull boxes from 14ga steel. We assemble with pop rivets. It works extremely well, and saves tons of time in the field where we know what our KO's will be, as opposed to having to field-punch off-the-shelf raceway. We can also tailor the enclosures to exactly the size / layout we need. instead of adapting something non-optimal but off-the-shelf.

We haven't had an issue yet. This arose due to needing to build some custom marshaling raceway sections to install over a pair of breaker panels. This will allow conduits to get into the panels extremely cleanly with as little field work as possible. I'm not anticipating an issue as we've done this many times before - I just want to be prepared since this is a new AHJ we haven't worked with. We're not a 508A shop anymore, as it wasn't really benefiting us to carry that cost.


SceneryDriver

 

[petersonra]

The phrase "Type 1 enclosures don't have to be listed" gets tossed around here from time to time. I've even said it. I'm now in a position where I have to defend that statement chapter-and-verse. I don't find anything in 314.40 (314, Part III) other than construction specifications relating to material thickness, etc... Is this a case of, "code doesn't tell us we can't, so we can?"



Thanks,

SceneryDriver

It is pretty common for diy metal boxes to be made and accepted by the ahj.