We have recently dealt with a similar situation, and have concluded that: At least for NEMA 3R and NEMA 4, Yes, NEMA 250 = UL 50 type. The tests are worded slightly different.
Yes, you can self certify to NEMA NEMA vs. UL; NEMA rating shows compliance with tests. UL type shows compliance with UL50 and UL476C where applicable, essentially same tests as NEMA, and subjects the equipment to UL recognition and follow-up criteria. As for UL types, in our case, the UL type allows us to put into the listing report that the product meets the requirements of NEMA. I think that the inspectors are more familiar with, and are looking for the NEMA rating. By having UL list the product, we are having a 3rd party say we meet the NEMA. James Goedderz Product Safety Engineer Sensormatic > ---------- > From: Chris Wells[SMTP:cdwe...@stargate.net] > Reply To: Chris Wells > Sent: Tuesday, July 31, 2001 10:53 PM > To: 'emc-pstc' > Subject: NEMA versus UL type - enviromental ratings > > I'm looking for some feedback on NEMA versus UL type - environmental > ratings for faceplates of panel mounted components. > > * First reality check - Are NEMA housing ratings = UL type, number by > number? > * Second - Can one self certify compliance to NEMA ratings? > * Third - What is the difference between NEMA and UL type? I think of > the NEMA rating as a proof of design test = rating while the UL type wants > design verification at a deeper level? > * Forth - Do any of you care about UL types? Our sister divisions > design assemblies that use our components and use UL to inspect the > design. That is where the pressure is coming from over NEMA. > > > Our product line consists of components mounted to the door of an > industrial type enclosure. > A pollycarbonate faceplate frames an overlay that contains membrane > pushbuttons, embedded LEDs and a window to see our alpha numeric or > grahpic display. Between the faceplate and the enclosure panel is a > gasket to help keep out moisture, dust etc. > We can meet NEMA 1, 12, 3, 3R and for some designs 4 as long as the user > installs the component in an enclosure of equal protection. We have > tested our design at environmental extremes and it works well. > > Where it gets difficult is when UL wants an adhesive for the overlay that > is specifically qualified to our particular plastic over the range of > specified environmental withstand. They want more than a type test and > follow up construction inspection but a rather lengthy performance test > that goes beyond what we are prepared to do - as if we were the overlay > manufactures. Part of the problem is that we have a special additive to > the PC plastic - stainless steel fibers for ESD control. This is making > for special combinations. > > So what do others do? > Do you have overlay vendors that have coordinated recipe of > components/adhesive etc. that works with pollycarbonate from -40 to 60C > and comply to UL types (NEMA) types 1, 12, 3, 3R, or 4? > > Thanks for any FB you can give ! > > Chris Wells > Sen. Des Eng. > Cutler-Hammer > Pittsburgh Pa > well...@ch.etn.com > > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
