Jim, In my experience with various agencies, a reliably connected PE is achieved with an oxygen free connection. The preferred method is star washers under the lug and a locking fastener above. Most frequently I use a star - lug - locknut or locking screw The incoming PE to the product also needs a dedicated connection with no other internal PE connections allowed. These must be on an adjacent terminal. Flat metal-to-metal connections are not a good connection primarily because of the possibility of corrosion. Naturally this is not appropriate for line connections which normally have high current as steel star washers are not a good conductor. Since the PE connection has less than 3.5 mA or 50uA, the star is not a problem.
On occasion I have also used soldered connections into PCB wire pads. Don't forget your PE symbol 417-IEC-5019. Doug Powell Advanced Energy Industries. [email protected] ---------- From: GOEDDERZ, JIM To: 'PSnetPost' Subject: Reliably grounded List-Post: [email protected] Date: Thursday, October 09, 1997 11:17PM I would like to get an industry statement on what constitutes reliable Protective Earth Grounding. I reference IEC950, Par. 2.5, which states that "Accessible conductive parts ...shall be reliably connected to a protective earthing terminal within the equipment." Some safety agencies allow connection of the PE through a terminal block, and others require that the PE connection be made directly, before connecting to any component (including a terminal block). Can I get some response on what has been allowed, or required, in your designs? James Goedderz [email protected]
