UL Requirements

Status
Not open for further replies.

Designer69

Senior Member
gents, I'd like to get a clearer understanding of UL requirements...

what is the difference between UL recognized, UL listed and UL rated?

also what is the electrical industry criteria for having a component UL listed vs. UL recognized? meaning how do you know which pieces of elec. equip. in an installation should be UL rated?

and finally how are UL listed/recognized components related to OSHA requirements?

Thanks!
 

bphgravity

Senior Member
Location
Florida
The first thing you must understand about UL is that it is really two (2) distinct organizations. One is the standards development entity and the other is the NRTL listing / regulatory entity.

OSHA recognizes 4 standards development organizations - ANSI, ASTM, UL, & FMRC.

The standards developed by these organizations are used by the NRTL's to determine if a product meets the applicable standard for that product. A list of those organizations can be found here:

http://www.osha.gov/dts/otpca/nrtl/

So for exampl, lets say I manufacture a pool pump and want to sell it in the US. Pool pumps must be designed and built to the ANSI / UL 1081 standard. I can use any of the NRTL's in the list above to "TEST" and "LIST" my product as being ANSI /UL 1081 compliant.



The webpage linked below gives an explanation of the different types of UL marks and labels that may be seen on a product, including LISTED, CLASSIFIED, & RECOGNIZED. Each have a different and distint purpose. there is no official designation of "UL RATED" or "UL APPROVED"...


http://www.ul.com/global/eng/pages/corporate/aboutul/ulmarks/mark/#north
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
In a grossly condensed version, UL Listed means it can be used as-is for the intended purpose. UL recognized cannot, it must be used WITH something else.

UR (UL Recognized) also essentially means it cannot be used in any way other than as a part of ANOTHER UL listed assembly. So for example all "ice cube" relays and the sockets they plug in to are UR, not UL Listed. They must be used TOGETHER in an assembly that someone else is going to re-list, such as a UL 508 panel Shop. In addition, most mfrs only list their relays with their own sockets. Most people don't realize that and freely interchange them because an octal socket is an octal socket, but nonetheless it's technically a violation of the UL Recognition. The same is true for "Motor Circuit Protector" magnetic-only circuit breakers, they are UR, not UL, so they CANNOT be used in the field for anything other than direct replacement of exact part numbers, because their UR requires that they be used in UL Listed factory assembled and TESTED combinations with specific overload relays.

So how does that relate to OSHA and electrical equipment? It doesn't. OSHA is about worker safety, not installations. But local codes will likely require inspection and although local AHJs can evaluate suitability, many jurisdictions require NRTL listing (not just recognition). That means you may do it on your own, but may suffer the consequences and be forced to re-do it, which is FAR more expensive than doing it right the first time.
 

Designer69

Senior Member
ok so then what are your thoughts on this specific application:

we have a centrifugal fan directly coupled to a 100HP (480/3ph) motor that is controlled by a VFD.

all these components will be field assembled. The motor is UL recognized not UL listed.

How will this affect this installation? Would you recommend getting a new motor? Or is there a method of evaluation to keep this setup?

thanks
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
A motor is not a switching or protection device, totally different issue.

But if you are going to UL list the entire machine it is being used on, in this case the fan as an assembly, then the UR on the motor becomes part of your procedure. if however you are the end user putting this together yourself, technically an AHJ could challenge it.
 

Designer69

Senior Member
Does the motor actually have a UL mark on it?

yes it has the UR mark on it. how does this implicate the setup? (what if it did not have it?)

A motor is not a switching or protection device, totally different issue.

this almost implies to me that only protection devices are required to be UL rated and non-protection devices are not required to. But I doubt it's that simple
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
yes it has the UR mark on it. how does this implicate the setup? (what if it did not have it?)

It means as Jraef said, that it is recognized as a part of a specific assembly - I have no idea what it may be.

this almost implies to me that only protection devices are required to be UL rated and non-protection devices are not required to. But I doubt it's that simple
It isn't quite that simple, but close enough for most purposes.

All kinds of utilization and "non-protection" equipment, are listed - transformers, heaters, luminares, consumer products, etc. However, in general, motors that are not a "recognized" part of a specific assembly are not listed. For reasons of their own, NEMA manufacturers do not submit general purpose motors for NRTL certification. That's why I was surprised a 100hp motor was marked at all. You can contact UL and ask what the recognized "specific assembly" might be.

Edit Add: Link to UL "Recognized Component" Guide
 
Last edited:

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
yes it has the UR mark on it. how does this implicate the setup? (what if it did not have it?)
...
this almost implies to me that only protection devices are required to be UL rated and non-protection devices are not required to. But I doubt it's that simple

I'll try this again, sorry I made it unclear.

It it were a switching or protection device, a UL508 panel shop could add it to their procedure and use it without having to be re-tested by UL. No such program exists for other assemblies, so UL testing and approval of the entire assembly becomes necessary.

A motor will be UL listed if it can be, but that means it meets certain specifications, some of which may be considered "over kill" to an OEM that doesn't need them all because they are using it in a specific way that precludes them. So the OEMs can get away with something a little less universally acceptable but more importantly for them, less expensive. If for example you are the mfr of an air handler unit, and you want to get a UL label on the entire air handler unit, then the fact that you use a UR motor means that you circumvent testing on THAT component going into the Air Handler and UL will evaluate it based on how you used it inside, which lowers the cost of testing the entire unit.

If you are not tan OEM, a UR mark means, to an inspector, that this motor was designed for a specific use and he will have to take responsibility for evaluating how you used it. Some AHJs will not do that, opting instead for insisting that you use NRTL LISTED devices. So if you are NOT an OEM, then using a UR motor puts you at risk of getting a red tag. You might get away with it, but you are taking a chance, the consequences of which should be weighed against the cost of buying a Listed version, if one exists.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Sorry about that last post. brainfart . We have some exhaust fans that have motors in them that our ul rcognized so it must not be that rare.
UL "Recognized Component" motors are, in fact, quite common. UL "Listed" (general purpose) motors are non-existent. UL does list motors for hazardous locations.
 
Status
Not open for further replies.
Top