Dear PSTC Members, Assuming a manufacturer had UL1950 Third Edition Recognized Component Class I (earthed) ITE Power Supplies and they wanted to have a Listing (as an open-end device) to the Standard for Industrial Control Equipment, UL508.
1) What additional requirements must be met? I am already aware that the input/output terminal blocks must be suitable for field wiring. 2) What about spacings? 3) What about if the input terminal block design is such that the earth goes directly to the PCB trace? Under UL1950 Recognition this was OK since the manufacturer decided to add a Condition of Acceptability (instead of meeting a 1000 Amp short-circuit test) that states that the power supply earthing terminal is not the protective earthing terminal and that this terminal should be reliably bonded to the end-product protective earthing terminal. Since manufacturer intends to also List his power supplies to UL508, this Condition of Acceptability must be removed and I wonder if the UL508 standard has a similar 1000A test as applied to to ITE equipment where the trace is relied upon for protective earthing! 3) Any other considerations for Listing to UL508? Thank you all, --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
