Glen, Norway, Sweden and Finland are correct. The Finish deviation for this is somewhat hidden, it is in clause 6.2.1.4, where it states that Earth Ground is not permitted as a level of protection between Mains and TNV. Double (BASIC + SUPPLEMENTARY) or REINFORCED INSULATION between is all that can be relied upon. You can only rely on Earth Ground if your equipment has a permanent connection to Earth Ground, or if it is plugable equipment type B (Industrial). The Swedish Deviation is in clause 6.3.3.1, and the Norwegian deviation is in clause 6.2.1.2.
I wonder...why couldn't they all make life a little easier and address this issue in the same location? Oh well... Mel Pedersen Midcom, Inc. Homologations Engineer Phone: (605) 882-8535 [email protected] Fax: (605) 882-8633 ---------- From: Lesmeister, Glenn[SMTP:[email protected]] Sent: Friday, October 09, 1998 12:14 AM To: 'Rich Nute'; [email protected] Cc: [email protected] Subject: RE: Crepage/Clearance On Telecom Modem design 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:[email protected]] Sent: Thursday, October 08, 1998 8:54 PM To: [email protected] Cc: [email protected] 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 [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
