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PaulKraemer

Control Panel requirements UL-508A, NFPA 70E, NEC

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Hi, The company I work for has been building machinery for the past 25 years. We used to have a full time electrician who designed, laid out, and wired our control panels in house. He was very knowledgeable and I am very confident that he followed good, recommended practices. We never had any complaints from any of our customers, some of which went through pretty extensive validation procedures. I learned a great deal from him while I worked as his assistant. When he got sick and later passed away, we never replaced him. I took over doing the electrical designs, but rather than building and wiring the panels ourselves, I just do drawings and we now have our panels built by an outside company that specializes in control panel building. I basically copied our electrician's original designs and added, changed, or upgraded whatever was necessary to meet new requirements or to deal with the fast pace of change in industrial controls. The outside control company taught me alot and I feel like we have improved and fine-tuned our designs quite a bit in the eight years that I have been doing this. I can say that I always read our component manufacturer documentation thoroughly and I follow all recommendations for wiring and fusing of all components. For our wire sizes, I follow a reference chart in one of our vendor catalogs that is an excerpt from UL 508. Still, we have not had complaints from any of our customers. We are currently quoting a new project where the User Requirement Spec says the following............ The Vendor shall ensure all electrical panels large or small meet all applicable codes: • Federal: NEC National Electrical Code, • Local codes: UL, 508A, and NFPA 70E. The Vendor shall provide the actual electronic readable and updatable MS Excel calculations spreadsheets and AutoCAD drawings showing measurements for the case of all electrical panels demonstrating compliance to NFPA 70E UL 508A, and other applicable codes requiring calculations, measurements etc.. .......... Additionally, they say that our control panels have to be "UL-508A Labeled". I am afraid to sign off on these requirements until I am sure I understand what is involved. I do not currently have a copy of the UL-508A, NFPA 70E, or NEC 2011, but before I buy these and take the time to read through them, I was wondering if anyone here has an idea of what kind of calculations and measurements are typically required to demonstrate compliance? And also, how can I get "UL Labeled"? Does this mean that I will have to hire an outside company with the proper authorization to inspect our control panels and give us the label? Any advice will be greatly appreciated. Thanks in advance, Paul

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We are a UL listed shop. We had to be trained and certified to do 508A and Explosion Proof enclosures. For the 508A, we usually do the load calculations and a few other details as required and put them on a sticker on the inside of the door along with a UL sticker. That sticker comes directly from UL, is serialized, and we have to document all the builds associated with each #, and are subject to periodic inspections for compliance in torqueing tools and methods, etc. If we were ever to be found to just inspecting someone else's work and stickering it we would be subject to fines and the possibility of losing our listing. I would not count on anyone doing this for you, the build has to take place at the address the UL listing is assigned to. Hope this helps

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Hi Shiner, Thanks for your response. I had no idea, but it turns out that the shop that builds our panels is UL listed. Being familiar with our panel designs as they have built about 10 of them for us already, they say that they don't forsee any problem being able to give us the UL sticker as long as we provide them with a bill of materials proving that all components we use are UL listed. That has me feeling pretty good about UL, but I figured while I am at it, I might as well ask you about CE. On another job I am trying to quote that might end up going to Europe, I might have the requirement of putting the "CE" logo on our machine. We do try to use all CE components in our builds, but I know that there are many CE directives and I am not quite sure how to determine which directives I need to comply with. Our machines are fairly large. Each has one or two main control panels from which we run wires in conduit to different locations to power and drive motors, to fire solenoid valves for our pneumatic systems, to support operator controls like pushbuttons, selector switches, and other "smarter" controls (for example tension controllers) that are located at the point of control rather than in our control panels. I was wondering if you put the CE label on your control panels, and if so, if you could give me a clue what directives I should pay attention too and if you could tell me anything else I need to do to be able to put the CE label on our machines. Thanks again for your help, Paul

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CE is much more involved than a UL listing. There are several directives associated with the electrical assembly, in addition to the machine safety directives that are purely mechanical. They also like to tweak those directives. Even if every part you use has a CE mark on it, that does not necessarily mean your system meets CE. Almost all manufacturers have caveats in their CE declaration of conformity that you must meet certain conditions during installation. The testing for CE involves injecting electrical interference into the system and looking for malfunctions in addition to measuring emanations from your equipment, among other things. Also, all equipment labels and push-button legends, displays, etc. must have the native language of the country where the equipment will be installed. That one is obvious to the customs agent if it is not present. I would highly recommend bringing in a consultant to do those inspections before slapping a CE sticker on your equipment. It's an added expense, but it saves a lot of headaches. The one we use has been very helpful over the years. Hope this helps, Ian

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Thanks Ian, That is very helpful. I'm not surprised by your suggestion to get a consultant. It would be nice to be able the get a "CE compliance for dummies" book but I had a feeling it would be more complicated than that. I see you are in Colorado. Does the consultant you use just work in your area or is he/she part of a larger outfit that serves other states? (I am in New Jersey). Thanks again, Paul

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Glenn is based here in Colorado, but I know he is not limited just to local jobs. Haven't needed him for a few years, so not sure how busy he is right now. I am not sure what the protocol is for posting independent links on this forum. If you would like his contact information, PM your email, and I will send his email address / web site.

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