UL 508A Class

Today I went to UL's class on 508A Industrial Control Equipment

Link to UL University site for class

The instructor, Tim Fitzjarrald, made a really dull subject interesting and was able to summarize some of the more complicated sections of the code to the real "meat and potatoes" of what is required.

For your $400 class registration you also get your own printed copy of the standard, a copy of the power point presentation and a few other goodies.

There is a lot of information to cover and my head is still whirling a bit from it all. This could almost be a 2 day class but they probably figure less people would sign up for it then, especially those who have to travel to take it.

At the end they covered Short Circuit Ratings which will be mandatory on 508A panels in April 2006.

Hey Norm, that's great! I just ran across this thread doing a UL search, missed it completely on 7/1 and succeeding days.

Are you guys a U/L panel shop at the present time? Or did you take this in anticipation of getting Listed?

The short circuit testing has me intriqued. I spent two years on contract in the GE plant in Bloomington, right after the "Lightning Machine" was sent to Connecticut. Can you give me a two line explaination of what a small plc enclosure will have to go thru? I don't really want to blow a panel to smithereens like GE had to for it's combination starters.

If I remember correctly, (lately a problem), I think if you arrange for the UL class to be held in your own facility, they actually do take two days to cover it (At $895 per student).

I want to go to the class. But it doesn't look like that will happen for a little while yet. One prospective employer has no money for anything yet, including (especially) wages. Another, who is backed by a large chain supply house operation thinks a family of 4 CAN live on the national poverty level wage for a family of 4.

Time will tell.

best regards......casey

Hi Casey,

We are in the works for getting approved as a UL 508A builder. I am currently working on the job which will be our first inspection.

The short circuit testing has me intriqued... Can you give me a two line explaination of what a small plc enclosure will have to go thru?

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It's not so much testing (which you could do also if you want) but a calculation method to give the panel a short circuit rating based on the SC ratingings of the branch circuit protectors and loads in the panel. They said this area is in flux right now. Newly listed components will have SC ratings on them but older devices may not.

For instance if you have a Circuit Breaker without a SC rating, you can assume a maximum rating of 5kA. Of course, as in any good specification, there are exceptions. There are other Assumed maximum short circuit ratings for other unmarked components in table SB4.1 of UL508A.

If you do your calculations and are happy with the rating then fine, you can put that rating on your panel. If you think, in reality, the panel will withstand a higher rating and you require it, then you can have it tested (at your cost) and then for that panel you can get the tested rating. I hope you need to make a lot of that same panel as it sounds like your testing is $3k minimum.

Hope this wasn't too confusing.

Ah yes, clear as mud.

Your explanation made much more sense than I got out of the U/U site.

U/L does like to charge you several thousand $$$ every chance they get.

I was surprised when I heard the class was only $400.00. At one time, they were talking like it may be closer to $2,000.00.


So, I imagine you're using a Moeller plc on your project. One of the big ones?

regards.....casey

So, I imagine you're using a Moeller plc on your project. One of the big ones?

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They haven't made it easy on me (couldn't they pick an easy one for the first UL Inspection ). The job is actually 3 free standing enclosures. The main will have a PS4-341-MM1 (Not the biggest PS4 which is a 416 I think or the big new XControl Which is a 600... I'm told those are more geared toward very large process control). Anyway, also in the main will be a 15" OIT (Moeller MV4), 6 Moeller VFD's (actually re-branded Hitachi drives), a couple self protected combination Moeller motor starters, a burner controller, high temp controllers, a converter to talk to the burner controllers on Modbus etc. The other two panels will be similar with less drives, their own burner controls and only distributed I/O (no PLC in those).

The thing will eventually talk to two other devices on the Moeller Suconet K network (Their brand of RS-485 network maybe akin to DH+). This is also how the remote I/O is accessed.

U/L does like to charge you several thousand $$$ every chance they get.

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Oh yes, the "not for profit" corporation...

I'm sure I'll post about the effort after the inspection.

Take Care

ndzied1 said:

Oh yes, the "not for profit" corporation...

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There is a lot of profit in non-profit.

Do you think all panel shops will have to be UL approved soon. We have no plans to be listed. Our customers do not care. We follow good practices, and have never had any problems other then program bugs and normal component failures.

Thank You

Paul

No, this is truly a customer driven requirement. Like QS9000 or whatever the latest paper generating storm is called now. If your customer requires it then you have to do it or find other customers.

Pretty much, if you follow the NEC and NFPA 79 your panels should be safe. UL requirements mostly follow the NEC with some added details and a lot of attention as to how things are labeled and marked. I think it depends a lot on where the panel will be installed. If the AHJ (Authority Having Juristiction AKA local inspectors) require UL approved panels then you have no choice. The UL instructor said many of these guys are requireing UL approval simply because they don't have the time to inspect all panels under theier authority themselves and if they see the sticker they can just say ok and go on to the next inspection.

This is only my take on the situation, YMMV (Your Milage may varry).

nOrM

We follow NEC and NFPA 79 closely.

We sent a couple of machines to Portland, OR. We were unaware that the local codes require UL listing of panels. They were field labeled without any problem.