Can Industrial Control Panel replace Panelboard?

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MWL_WMTK

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Control Engineer
Hi All!

It is my first post here - please be gentle :)

I am european Automatic Control Engineer. Together with my customer, which wants to storm North American market :) we look for proper solution for low-voltage distribution board, powering relocatable medical examination centers (container-type and trailer-type). At the moment we are not talking about NFPA 99 - we are still analizing if any of it's chapters would apply to our case.

General overview for our distribution board - it is used to protect lighting, sockets, AC, some medical examination devices (those are only end-nodes for us - well know manufaturers existing in noth amercian market), sometimes hydraulic agregate for container leveling stamps. Whole set powered via flexible cable with properly rated plug.

Since UL 67 Panelboards are not easy to get in Europe for manufacturing phase - my question is - can I project the distribution board according to UL 508a as it was Industrial Control Panel? Do You see any contraindications for such an approach? My case is not listed in PART 2 of UL508a, but can I treat it as "ICP intended for general industrial use"?

Why do I complicate so much? As I wrote above - it is not easy to get UL 67 style panelboard anywhere here in europe (not only enclosure but guts itself also). On the other hand many global suppliers like SIEMENS, ETAON, SCHNEIDER, ABB, etc. sell here in europe DIN mounted devices, UL approved (like for example 489 MCBs) to be used on american market.

I would like to hear You opinions on that :)
 
Regardless of whether or not you build it as an "Industrial Control Panel", the basic principles of protection and it's ability to handle fault current will remain. So you will need to apply an "SCCR" label to your ICP stating the maximum available fault current, as determined in the UL 508A Supplement SB document. In a nutshell, you must EITHER submit the entire assembly for SCCR testing, which is VERY expensive (and destructive), or you must use devices that have a high enough SCCR themselves, or in a listed Series Combination, tested by the component manufacturers. So bottom line, you are not going to be able to attain that UNLESS you are using components that have these UL listings. This essentially puts you in the exact same place you are trying to avoid being in. You CAN apply a UL-508A listing on an ICP with what I call a "courtesy" SCCR listing of 5kA, which UL allows for untested unlisted devices, but this is basically useless because almost NOBODY has that little Available Fault Current, especially in something like a medical facility.

Bottom line, you need to discuss this with a supplier in your part of the world that can help you though this process because a simple mistake can render you end product virtually impossible to install at this end. Siemens and Schneider in particular make "world class" breakers and bus assemblies that should be available to you there, with ratings that are useable here.
 
Jraef said:
Regardless of whether or not you build it as an "Industrial Control Panel", the basic principles of protection and it's ability to handle fault current will remain. So you will need to apply an "SCCR" label to your ICP stating the maximum available fault current, as determined in the UL 508A Supplement SB document. In a nutshell, you must EITHER submit the entire assembly for SCCR testing, which is VERY expensive (and destructive), or you must use devices that have a high enough SCCR themselves, or in a listed Series Combination, tested by the component manufacturers. So bottom line, you are not going to be able to attain that UNLESS you are using components that have these UL listings. This essentially puts you in the exact same place you are trying to avoid being in. You CAN apply a UL-508A listing on an ICP with what I call a "courtesy" SCCR listing of 5kA, which UL allows for untested unlisted devices, but this is basically useless because almost NOBODY has that little Available Fault Current, especially in something like a medical facility.

Bottom line, you need to discuss this with a supplier in your part of the world that can help you though this process because a simple mistake can render you end product virtually impossible to install at this end. Siemens and Schneider in particular make "world class" breakers and bus assemblies that should be available to you there, with ratings that are useable here.
Click to expand...

Thanks Jraef for the input!

Yes of course - I am aware of that. For industrial machinery projects I make calculations of SCCR in accordance with supplemenet SB of UL 508A.
Typical scenarios I've done for machinery:
  • 480Y/277V Feeder
  • UL 98 fused current limiting disconnect switch in the feeder circuit
  • CC class fuses at 3 phase loads branch circuits
  • Isolated secondary winding step down transformer to obtain 120/240V - below this I use UL 489 MCBs for branch protection of lighting and outlets
We are not in Panel Shop Program but we've passed few field evaluations so far :)
--------------------------------

Last few days reading NEC I came up with such scenario for my case:

  1. I treat my container unit / trailer as Relocatable Structure acc. to NEC art. 545
  2. Container unit / trailer is fed up by pin & sleeve plug with flex power cable from the customer's Main Panel with receptacle
  3. My UL508A style ICP is a Sub-Panel for customer's Main Panel (EGC comes with feeder and I don't bond Neutral and Ground in my ICP / Sub-Panel)
  4. Field wiring inside container / trailer acc. to NEC art. 517 (it's Mobile Examination Center after all)
  5. I am still wondering if grounding rod would be necessary next to container / trailer - grounding electrode should be present not far away next to customer's Main Panel. Other way it would be not practical at all to plug the trailer with pin & sleeve and later hammer down rod into ground :), but I think I will post a new subject when I clarify more.
One more thing I can say why I push so much with ICP style sub-panel. In original European units we have some time ralays, indicator lights, etc. in the low voltage distribution boards. I think it is not posssible or very hard to obtain with UL 67 Panelboard. Another important thing - the unit draws huge currents (because of medical imaging devices inside). I can't imagine feeding it less then 240 V Delta High Leg at least, most probable it would be 480Y/277 V. I know that for 240 V 3P4W you can order a Panelboard but what about 480Y/277? More of this - I need to step down inside my unit to obtain also 120V for outlets and lighting - I don't think it is possble to fit 480-120 trafo inside UL 67 panelboard.

Anyone having some thoughts- I would be grateful for inupt :) Maybe any AHJ inspector reading this?
 
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