What you are seeking rather than an earth ground, is to tie the commons of the equipment you are working upon, and yourself, suitably protected by the wrist strap internal resistor, to the same point, and thus voltage potential. You are trying to have everything at the same potential before you reach toward a board with a conductive tool and provide a discharge point for any accumulated static on one side or the other.
The objective is to bleed off any static charge you bring on your body, clothes, etc., to the work table, to the static mat and to the common bus of the circuit board, chassis, or whatever is sitting on the pad. In other words, it matters not if the pad and you and the equipment float at some voltage, as long as you all become tied together so as to be at the SAME voltage. That is why you do not see any specific instruction to tie the mat to an earth rod. If you walk up to the work area and thus buildup a charge from walking along; as soon as you strap on the resistive wrist strap tying you to the other equipment, you dissipate the charge thru the resistor or induce the same charge to whatever you are working upon. The earth itself does not have any magical property to effectively nullify static; rather, you attempt to spread the charge evenly among all conductive elements involved in your workbench. Sometimes earthing thru a rod might aid in keeping the bench from rising up in charge itself, but the risk of that is tied to such issues as is there a steady wind blowing across metal surfaces, or is the air around the bench very dry and cool, thus facilitating static charge accumulation. -Stuart K5KVH _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
