UL listed components vs UL listed assembly

[ehawks]

UL Listing of Equipment

UL Listing of Equipment

I have had a fair amount of experience in this area doing electrical design for Industrial and Muncipal Water and Waste Water Treament Systems. It used to be that you could engineer a control system using listed components and be fine. UL has been lobbying electrical inspectors (what happens in Vegas stays in Vegas) and more and more of them have been insisting on UL508 or UL698A control panels. Most of the vendors that build control systems in our business are certified (for a fee of course) by UL to construct these panels or control systems. Per job it ends up only costing an extra $100 per job. As consulting engineers we simply cannot afford to take a chance on who is doing the inspection and what their intrepetation of the NEC is going to be . What sealed the deal for us was we had an inspector that condemed a muncipal project in Michigan ten years ago that had 27 control panels on it. This was for a new water and waste water system. We argued that the components were all listed but the inspector cited the god clause in 110.2. We tried to convince the inspector that 110.3 was his job to do and he said your are right and I want UL 508 or 698A under the god clause in 110.2. Contractor, engineer and owner ended up splitting a 3 way bill or $20,000 of UL field inspections. From that point on we don't even mess around with this and always specify UL listed control panels as an assembly. Can't afford not to. You have to hand it to UL because they are doing a good job justifying their existence. More and more of these inspectors are just riding around in trucks looking for stickers. Could pay an illegal imigrant to do that.

 

[augie47]

Nrtl

Nrtl

ehawks, From a different prespective, I have the same experience. TN is a "NRTL" required State. Over the years I don't know how many equipment manufactures have ended long winded arguments with a statemet "Oh, You're one of THOSE States". A lot of them have the option of providing NRTL listed equipmet but don't unless the customer requires. I've seen a lot of folks have to change out equipment or components to satisy that requirement.
My experience has shown that a group of components with UL or UR listings does not in any way guarantee the end product meets all safety standards. There are many "listed" 20 amp fuses, each with different specifics such as let thru current. Just because the fuse is "listed" does not mean it was designed to work with the "listed" controller it is protecting. The NRTL as a finished product assures each component is desiged to work with the others.

 

[AltonToth]

A friend's company up here in BC Canada was building temporary power panels for work sites (to be sold). They designed and built them from the ground up, but all components of the system were ULC approved. When they got it all together, it only cost them something like $250 to have a ULC inspector come out and check the panel. For a limited production run of less than 10ish units, they just needed to pay that one-off fee to have all the panels approved (whether they be made at the time or not). Just a different perspective.

 

[petersonra]

Ok, I always seem to get these, spend countless hours researching, come up with nothing and then bug you guys on these forums - I guesss I am trying to say Thank you! Anyway, I have a 3 phase rotary phase converter, manufactured by American Rotary. The unit is installed and everything looks good, inspector has no problem there. But as he was walking away, he asked about the UL listing, there is not one on the control panel. I called the manufacturer and they said the components are all UL listed, TRUE, including the hoffman enclosure... But the assembly is not. And that it is usually (???) not a problem. Now I have to have an answer for my inspector - Any suggestions short of throwing this $1000 bucks in the trash and buying one from someone else?

Is the rotary phase convertor UL listed? Why doesn't the EI care about that?

It is possible for the control panel itself to be field inspected and a UL label applied if it is acceptable. Probably less then $1000.

 

[Inspectorcliff]

Question how about them UL's

Question how about them UL's

We have a company who builds controls for large irragtion (irrigation) pumps and motors, controls, VFD's. Question? If the VFD has a label that reads 3 phase in xxx amps and xxxx volts and reads 3 phase out xxx amps out and xxxx volts out. Would it be acceptable to feed this with a 200 amp 120/240 volt single phase service? The Hoffman box is UL, the components are UL, the Wiring is UL, BUT, the skid and the complete package has no UL listing.??Thanks?

 

[philj639]

UL listed components vs UL listed assembly

Roger, I'm sorry I have to strongly disagree with your answer to Horst1. I work for MET Labs, a Nationally Recognized Testing Laboratory.

#1 - Horst1 ..."Anyway, I have a 3 phase rotary phase converter, manufactured by American Rotary. The unit is installed and everything looks good, inspector has no problem there. But as he was walking away, he asked about the UL listing, there is not one on the control panel. I called the manufacturer and they said the components are all UL listed, TRUE, including the hoffman enclosure... But the assembly is not...."

Each one of the components is Listed under a specific UL standard for that component. For example: the three phase rotary converter that Horst1 is referring to may fall under UL1741 (Inverters, Converters, Controllers and Interconnection System Equipment for Use With Distributed Energy Resources).The standard for electric motors is UL1004. Many component certifications are actually recognitions and are dependant on the installation of the end product. Recognized components can be identified by the U with a backward R.

Once all of the components are installed in the final product a new standard applies to that product. In this case, UL508a (Industrial Control Panels) would apply.

Roger, you really can't compare an industrial control panel or any electrical machinery to a residential house inspection. The electrical contactors are required to be licensed and take continuing education in order to continue to practice their trade. This helps ensure that as they are installing all of those "Listed" components in a house, they are still following the National Electric Code. The electrical inspector then reviews the work adding another level of safety.

Roger, if I understand what you are saying, then the equivalent analogy would be that as long as residential electrical contactors are using certified components, then there is no need for the electrical inspector.

We should all know that certified components can always be connected in such a way as to as to produce a hazard. Good Example: lets assume Horst1's panel is wired with Listed 14AWG conductor that is protected by a Listed 50amp fuse. Per NEC, the 14AWG conductor shall be protect at 15amps or less.

#6 Roger, ..."inspectors are relying on a crutch to approve something instead of their knowledge"..
Product safety standards have been written to address the specific products through the underlying intent of the NEC. Most inspectors do not have the time, the training or the resources to maintain, the thousands of product standards required. Third party testing agencies do.

If anyone would like to contact me with questions or comments, please contact me by PM

Best regards,

Phil Henning

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[petersonra]

Why would an inspector accept a UL listing for Industrial Control panels for something installed in a residence anyway?

PART 1 ? GENERAL USE INDUSTRIAL CONTROL PANELS
INTRODUCTION
1 Scope
1.1 These requirements cover industrial control panels intended for general industrial use, operating from a voltage of 600 volts or less. This equipment is intended for installation in ordinary locations, in accordance with the National Electrical Code, ANSI/NFPA 70, where the ambient temperature does not exceed 40?C (104?F) maximum.

 

[megloff11x]

UL et. al. have the high dollar test gear and encyclopedic knowledge base on things we don't think about. Having dealt with safety inspectors of various flavors and levels, sometimes half of it seems like they're pulling it out of that place where the doctor looks for polyps. That said, it's our job to do our best, and theirs to test us.

The lawyer will slobber if you say you didn't have them go over it, or slump back into his chair and sulk when you did and it passed.

Be aware that a listing implies a particular limited set of applications. If your application isn't on that list, their stamp is as meaningful as a logo on a NASCAR.

Matt

 

[dwconsult]

In a previous life, I wrote for a computer magazine and visited the Santa Clara, CA UL facility, spent a day learning the whole works. This was re UL of personal computers but the issues are much the same, and Tony hit it on the nose.

The interaction and resulting possible hazard from overheating, electrical interaction, etc, of all the possible UL listed devices that could be put together into one assembly are impossible to foresee. The process and some of the staff may be a pain, but they are charged with safety concerns that we all know would get left behind in the rush to save a buck or a few minutes time.

I remind myself of this often when driven nuts by UL issues I'm now living with myself.

 

[weressl]

Ok, I always seem to get these, spend countless hours researching, come up with nothing and then bug you guys on these forums - I guesss I am trying to say Thank you! Anyway, I have a 3 phase rotary phase converter, manufactured by American Rotary. The unit is installed and everything looks good, inspector has no problem there. But as he was walking away, he asked about the UL listing, there is not one on the control panel. I called the manufacturer and they said the components are all UL listed, TRUE, including the hoffman enclosure... But the assembly is not. And that it is usually (???) not a problem. Now I have to have an answer for my inspector - Any suggestions short of throwing this $1000 bucks in the trash and buying one from someone else?

The difference is that a house wiring with UL listed components is covered by the NEC. Work done in an enclosure from UL Listed or Recognized components are covered by other stanards. If the Panel Shop is a UL authorized shop and they have a set of UL standards that they follow then they can design, manufacture and UL label a panel. Otherwise the panel is just a bunch of listed/recognized devices assembled without an overall label. It is of course commonly done, but it is an area that is not adequately covered. New panels that carry power, not just control need to be rated fro SC withstand and proper arc-flash labeling and there is no way a panle manufacturer will take the liability on taht without a third party label. Control enclosures still need to have proper clearences, follow the manufacturers(component) instructions, voltages segregated, etc. Like we need more regulations....

 

[roger]

Phil, just so we're on the same page, I never said that using listed parts negated having an installation inspected.

If I build something out of listed componets and the final product is not required by the NEC (or local codes) to be listed, such as an Industrial Control Panel, I would expect that an inspector using article 409, UL508, and his/her electrical knowledge could evaluate it for safety.

To be clear, I am not talking about building an Industrial Machine, I think you and I are in agreement on that issue.


Roger

 

[Jraef]

Phil, just so we're on the same page, I never said that using listed parts negated having an installation inspected.

If I build something out of listed componets and the final product is not required by the NEC (or local codes) to be listed, such as an Industrial Control Panel, I would expect that an inspector using article 409, UL508, and his/her electrical knowledge could evaluate it for safety.

To be clear, I am not talking about building an Industrial Machine, I think you and I are in agreement on that issue.


Roger

I think that is the case if you live in a "non-NRTL" state. But I also think they can jack your inspection fees as well when they have to do that.

I know that when Boeing got the NRTL requirement amended in Washington State in the late 80's to allow field inspectors to accept panels if the company had an in-house engineering staff, the inspectors countered with horrendous fees. Their argument was that it was justified since now, instead of coming out and looking for a label, they had to spen hours pouring over 300 parts in a box and and manufacturer's documents to investigate their appropriate use. Boeing soon discovered that it was usually cheaper to just buy listed panels.

 

[hdpeng]

This link will help you get started:

http://www.ul.com/services/submittal.html

 

[roger]

This link will help you get started:

http://www.ul.com/services/submittal.html

David, in the OP's scenario there is no requirement for the components to be listed as an assembly so there is no reason to spend the money or time to go through the process.

Roger

 

[hdpeng]

David, in the OP's scenario there is no requirement for the components to be listed as an assembly so there is no reason to spend the money or time to go through the process.

Roger

I agree with you Roger. I'm just passing on general info for direction to UL listing info. I once had a client that insisted on a UL listed assembly when all they needed was an assembly containing UL listed components to satisfy their insurance underwriter. The only way I could convince them was to explain the process of getting a UL listed assembly [submit 2 complete assemblies (1 for NDT & 1 for DT) with all backing design documentation], pay mucho $$$, and wait 6-8 mos. for approval. Their biggest problem was that they were constantly updating circuitry in the unit by putting newer technology cards in to replace older technology, so when they did that they would have to re-apply for a new assembly (more time & $$$).