Fred, Your statement of connecting to an equipotential plane is a good one, but your concern about spikes and inductive reactance back to the "planet" should not be a concern. It IS important that all items in the protected area be connected to the SAME point on this safety ground. Connecting one ESD prevention device to one green-wire ground, and connecting yet another device to yet another receptacle's green wire ground will cause a difference in potential between those two points on the green-wire ground.
The same principles apply to installations like commercial broadcast stations which must remain in operation throughout a lightning storm. The solution is to keep everything in the station at the same potential through the use of a "grounding window" - which is the single point to which *everything* in the station is connected. In the event of a strike, it does not matter whether that grounding point raises to several thousand volts - everything connected to that point will also rise in potential by that same amount. It is the potential *difference* of those items that are connected to that single point that is kept to a minimum. It takes a potential *difference* to cause harm or damage. It is similar with ESD protection, but on a much smaller scale. Do not connect your wrist strap to one receptacle ground screw and your anti-static mat to yet another. Connect them all to the same point. Failure to do so destroys the design of your anti-static setup. And that is the reason that many anti-static mats have a connector where you can attach your wrist strap - use it to keep everything at the same potential. 73, Don W3FPR On 12/18/2010 6:19 PM, Fred Jensen wrote: > Connecting your equipotential plane to the planet is a mixed bag. If > the connection is direct and big, it's probably fine. If other things > use it and might put significant current spikes into it, you might want > to reconsider. It's sometimes surprising the amount of noise pulses > that can wander around on the "green wire" in a normal residence. If > your house is wired to code, it's connected to the neutral and the > planet at the main electrical entrance [only], which could mean quite a > bit of wire to your shack and lots of inductive reactance in it for very > fast pulses. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
