Basic UL508A question

[fncruz]

Does EVERY component in a control panel need to be UL certified or listed for the panel to be UL508A certified?

 

[petersonra]

Does EVERY component in a control panel need to be UL certified or listed for the panel to be UL508A certified?

Ul508a is a listing, not a certification.

With a few exceptions, all parts have to be UL listed or recognized. But you cannot use just any UL listed or recognized parts. There is a list on their website of what UL listed or recognized parts can be used. See supplement SA. It is part of the standard but is maintained on their web site.

 

[EC Dan]

There are a lot of different UL standards, the supplement that petersonra is referring to tells you what the specific requirements are to use something that is listed under a different standard:

UL 508A Supplement SA Specific Component Requirements

This document is intended to be used to determine the requirements for components when used in industrial control panels.

www.ul.com

 

[petersonra]

There are a lot of different UL standards, the supplement that petersonra is referring to tells you what the specific requirements are to use something that is listed under a different standard:

UL 508A Supplement SA Specific Component Requirements

This document is intended to be used to determine the requirements for components when used in industrial control panels.

www.ul.com

A fair number of the parts in supplement SA are not listed but rather recognized.

You can also pay UL to get stuff added to your report so you can use them, if they agree to it. Sometimes this is pretty straightforward, others times kind of convoluted. Usually the simpler things are just about paying for the privilege of using parts not already allowed.

 

[Jraef]

You need to understand the difference between "listed" and "recognized" as well. Listed components (UL symbol in a circle) can be used for their intended purpose somewhat freely by a UL-508A listed shop. Recognized components (UR symbol with the R backward) means they can ONLY be used in combination with another listed or recognized component in a narrowly specific way. A classic example is that plug-in relays are UR because they must be used with the SPECIFIC plug in base (also UR) that they were recognized with. Lot's of people ignore this fact, but UL can (and has) bounced people for it, i.e. using a Potter Brumfield brand relay with an Idec brand base. So for a panel shop to use Potter Brumfield relays, they must submit a form to UL to "add them to their procedure", stating that they will be used with the Potter Brumfield bases. In other cases you cannot just freely use certain types of components without testing. A case in point there are "MCP" (Instantaneous-Only) circuit breakers. they are all UR only, not UL listed. The conditions of use REQUIRE THAT THEY BE TESTED in combination with a listed motor starter as an assembly, and that testing is VERY expensive. So in effect, MCPs end up only being used by factories that build combination starters.