Definite purpose contactor

[Fordean]

Like to hear what exactly is a definite purpose contactor Which example of its use full load capable? Continuous load?

 

[Jraef]

DP contactors are simply the cheapest form of contactor a manufacturer can make, for a SPECIFIC use (“definite purpose”) by an OEM who buys them in high volume and uses them as PART of an assembly that will then be UL listed as a complete unit that the IEM will fully engineer and usually to only last at least as long as their warranty. In that engineering process, the OEM will know exactly what their system is intended to do, how often it will do it, how long it will rest between cycles and how long it will be expected to last. They then provide that information to the contactor manufacturer who sells them a DP contactor to do that ONE SPECIFIC task.

There is NO VALID USE of DP contactors outside of this, other than as DIRECT REPLACEMENT of exact part numbers. Yes, I know that people SELL them as if anyone can use them for anything, but that is not true, never has been. If you look, you will notice that no DP contactors are UL listed, they are UL Recognized (backward UR symbol), which means they can ONLY be used as part of a listed assembly.

It’s best to look at “DP” as standing for “Don’t Purchase”.

 

[steve66]

I've never heard that before. Do you have a reference for it?

Is there a NEC reference that says contactors have to be listed?

 

[jaggedben]

If a functionally equivalent part were listed what would it be called instead?

 

[ptonsparky]

I certainly used a lot of those DPs. Most for replacement, but if brand Q wasn't available S, F, or C went in. Usually a size larger if it would fit.

 

[LarryFine]

I certainly used a lot of those DPs.

Same here, often in kitchen fire-suppression systems, for example. Am I in trouble?

 

[ptonsparky]

Same here, often in kitchen fire-suppression systems, for example. Am I in trouble?

You, me and about every electrician other than ropers..

 

[tom baker]

I've never heard that before. Do you have a reference for it?

Is there a NEC reference that says contactors have to be listed?

Contractors are almost always used in a mfg enclosur, like a NEMA 1 starter, the contractor could be component recognized, with entire enclosure listed

 

[LarryFine]

If a functionally equivalent part were listed what would it be called instead?

Riddle us this, Batman.

Contractors are almost always used in a mfg enclosur, like a NEMA 1 starter, the contractor could be component recognized, with entire enclosure listed

Not to mention contactors.

 

[jaggedben]

Is there a NEC reference that says contactors have to be listed?

Still waiting for someone to supply this reference.

 

[ptonsparky]

Still waiting for someone to supply this reference.

110.21 is the closest I've found.

 

[Jraef]

110.3 (B) and (C)

The issue of Listed vs Recognized is a UL thing, but this sums it up fairly well. (emphasis added)

UL RECOGNIZED COMPONENT MARK (ALL VARIATIONS)​

UL Component Recognition means that UL/UL Solutions has evaluated components or materials intended for use in a complete product or system. These components are intended only for end-use products that may be eligible for UL certification.

Because UL Recognized Components are intended for specific applications, Marks or symbols using the letters “U-L” can never be used in connection with the advertising or promotion of UL Recognized Components. The appropriate symbol for promoting a UL Component Recognition is the UL Recognized Component Mark. Products using the UL Recognized Component Mark are never permitted to use a promotional badge.

Source:

 

[jaggedben]

110.21 is the closest I've found.

110.3 (B) and (C)

The issue of Listed vs Recognized is a UL thing, but this sums it up fairly well. (emphasis added)


Source:

Nope, nope and nope. All completely illogical.

110.21 doesn't contain any requirements that DPs don't typically meet, and isn't really relevant at all to the question of whether code requires them to be listed.

Regarding 110.3(B), the instructions for DPs don't typically contain anything saying that they can only be used in listed assemblies, and so as long as they don't there's no violation of that section.

Regarding 110.3(C), nobody is alleging that testing or evaluation is being done by other than NRTLs. But more importantly, if DPs aren't required to be listed then that section just doesn't apply.

As far as the quoted UL language, it seems like the main concern there is to prevent the inappropriate use of the UL imprimatur in advertising. But that doc is basically irrelevant because UL's intentions don't create an NEC requirement for all equipment to be listed. Also, who is to say that any given use doesn't fall in the category of what 'may' be eligible for listing as a product or system.

Jreaf I think your argument would be better served by citing 110.3(A), along with its IN no. 2 and UL citation. But ultimately the IN is nonbinding and the interpretation of suitability is subjective where the code doesn't impose clearer requirements. A clearer code requirement that DPs be listed has yet to be cited in this thread.

 

[tom baker]

Still waiting for someone to supply this reference.

If I had my AB or SQ D catalogs I could answer.

 

[steve66]

110.3 (B) and (C)

The issue of Listed vs Recognized is a UL thing, but this sums it up fairly well. (emphasis added)


Source:

So UL is saying we can't use a component or anything unless its certified by UL.

 

[steve66]

If I had my AB or SQ D catalogs I could answer.

I looked because it kind of seems like i may recall seeing some fine print disclaimer like that once for DP contactors, but my square d catalog says;

"UL Component Recoginized, UL Listed (Form U1), CSA Certified, CE Marked.... "all with a bunch of reference numbers.

I won't argue that they are probably junk, but I don't see any reason they can't be used for non-critical applications with limited switching, and limited power requirements.

 

[ptonsparky]

I'll admit. I used them as I saw fit.
I also knew that I was not supposedly capable of making a legal decision as to there proper application.

 

[Jraef]

"UL Component Recoginized, UL Listed (Form U1), CSA Certified, CE Marked.... "

If a device actually SAYS UL Listed, then it is listed, in this case in whatever manner "Form U1" means for that specific product. So in THIS CASE, Square D has PAID to test and LIST the device, when used under "Form U1", as a truly listed device. But UR (Recognized Component) is NOT the same as "Listed", it can only be used as PART of an ASSEMBLY that is itself GOING TO BE LISTED, by supplying UL with the details of how it will be used, with what, and how the entire assembly will be tested and listed.

When I was a UL 508A panel shop, we COULD use UR components, but only if we "added them to our procedure" and showed UL EXACTLY how they would be used, etc. Even then, if it was a "motor controller", we could not show an SCCR of the assembly greater than 5kA, regardless of what fuses we used, because WE were not going to pay the $25-40k to have the SC testing done, and the mfrs of DP contactors didn't either.

The NEC defines what "Listed" means, then UL defines that UR is not "listed". Parsing the words to fit an agenda or arguing that "everybody everywhere has been doing it this way for years" may be valid to some, but does not change the facts.

HERE is perhaps a better UL document pertaining to this issue. Note that this is a document intended for AHJs...

If you don't want to read the entire thing, here is the pertinent part.

If a Recognized Component is installed in the field, the only way for UL to verify compliance with a component’s conditions of acceptability is to conduct a UL Field Evaluation on the end product where the component is installed.

Trust me, you do NOT want to have to pay for a Field Evaluation by UL...

 

[jaggedben]

...

HERE is perhaps a better UL document pertaining to this issue. Note that this is a document intended for AHJs...

...

I get that UL would probably love it if every inspector everywhere required every component of every electrical installation to be listed. They'd argue it'd make installations safer, and they'd get paid more for testing more products.

I also get that as a UL shop you had to follow UL rules for the usage of components, not the NEC.

Nevertheless, the first paragraph of the that document ....

As a basis for approval, code authorities
look for UL Listing Marks to verify that
products have been investigated for
installation in the field in accordance with
model codes.

... is entirely optional for AHJs following the NEC, except where the NEC explicitly calls out for listing. It's a matter of how the AHJ wants to treat 110.3(A), which talks about listing only in a non-binding Informational Note. It also talks about labeling and identification which are things the code routinely calls out as requirements for components it doesn't require to be listed.

AFAIK, a contactor still isn't called out in the code as required to be even labeled or identified, although I wouldn't use one that wasn't and I wouldn't argue with an AHJ that called out such a use per 110.3(A). But if the AHJ tells me the contactor has to be listed, I'd ask for a more specific code reference, because lots of things in the code aren't required to be listed.

 

[jaggedben]

...

If you don't want to read the entire thing, here is the pertinent part.

Trust me, you do NOT want to have to pay for a Field Evaluation by UL...

But I wouldn't have to unless the AHJ asks for it.