[Elecraft] I need some grounding-strap guidance, if'n you please

[Wes Stewart]

Don,

For ESD purposes, we usually have a megaohm or so between the wrist strap/ESD mat to ground.  In the overall scheme of things, a J-bolt stuck in concrete is at worst a few more ohms in series with the current limiting resistor.

I almost added this in my prior message but thought better of it.  I guess that was a mistake.  Here is a thought experiment (Don't actually DO this).  Put one had on the J-bolt and the other on the hot side of the AC line and report back as to whether the J-bolt is grounded or not.

A Ufer ground is nothing more than that tied rebar you mention and it's entirely encased in concrete.  The concrete is the connection to the earth, not the steel.

A way I often look at things is to consider the opposite condition.  What if I wanted that J-bolt to be insulated from ground?  What steps would I have to take to make it so?  Something other than sticking it into wet concrete, that's for sure.

Regards,

Wes  N7WS


--- On Mon, 8/31/09, Don Wilhelm <w3fpr at embarqmail.com> wrote:

From: Don Wilhelm <w3fpr at embarqmail.com>
Subject: Re: [Elecraft] I need some grounding-strap guidance, if'n you please
To: "Wes Stewart" <n7ws at yahoo.com>
Cc: "Peter N. Spotts" <kc1jb at arrl.net>, elecraft at mailman.qth.net
Date: Monday, August 31, 2009, 4:25 PM

Wes,

I have built several houses myself, my father was a masonry contractor, and I have seen many installations of J-bolts in foundation sills - I have never seen any of them grounded - they are simply stuck into the concrete filling the blocks.  It may be different with poured foundations where the rebar is tied before pouring and it may be different in commercial structures, but for residential structures, I would never consider the J-bolts as an adequate ground for  anything at all.

73,
Don W3FPR