In most cases, Norway, Sweden and Finland? require supplementary insulation for a primary circuit between TNV and Ground\/SELV. Assuming a primary circuit of 250VAC, I believe this works out to 2.5mm creepage and 2.0mm for clearance (I don't have my standard handy). In addition, you need 0.4mm thickness through the board, or sufficient multi layers per 2.9.4.
Diaco, you didn't mention whether or not the product is intended for world wide distribution, so be careful not to disregard these additional requirements for these regions. I've heard that Sweden is considering a compromise that might remove the distance through insulation requirement, but still hold the line creepage and clearance, however, I don't know if and when this will take effect. Glenn -----Original Message----- From: Rich Nute [SMTP:ri...@sdd.hp.com] Sent: Thursday, October 08, 1998 8:54 PM To: dav...@pmc.philips.com Cc: emc-p...@majordomo.ieee.org Subject: Re: Crepage/Clearance On Telecom Modem design Hello Diaco: My reading of Clause 6 of IEC 950/EN 60950 is: between TNV circuit and primary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the primary circuit to the conductive barrier. between TNV circuit and hazardous voltage secondary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the hazardous voltage circuit to the conductive barrier. between TNV circuit and SELV circuit: no creepage distance or clearance requirement (but, it must pass the hi-pot test) between TNV circuit and ground: no creepage distance or clearance requirement (but, it must pass the hi-pot test) Creepage distances are measured along the shortest path between the two conductors across the surface of the insulator. There is no correspondence to traces on opposite sides of printed wiring boards (because such insulation is interposed solid insulation, and MAY be subject to insulation thickness requirements). Best regards, Rich --------- 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). --------- 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).