[Elecraft] Bare Foot

[Jim Miller KG0KP]

The heel straps we wore in the factory had a strap that went up your leg and 
connected to bare skin above your socks with a conductive band with velcro. 
There wasn't any expected conductivity through your shoes.  And for 
additional information, they were only valid on floors with conductive mats 
or floors that had been modified with concuctive surfaces that were 
connected to the ground network.  The pain was leaving the protective areas, 
we had to remove them so they wouldn't "get dirty".

Static damage generally isn't immediately detectable and will fail later or 
cause degraded performance.  Just becaues it "still works" doesn't mean you 
don't have static damage. We had electron microscopes (the company, not my 
job but we got to look at the damage) they used in diagnosing cause of 
failures and it was easy to see damage.

73, de Jim KG0KP


----- Original Message ----- 
From: "Mark Bayern" <plcmark at gmail.com>
To: "Wes Stewart" <n7ws at yahoo.com>
Cc: "Elecraft List" <elecraft at mailman.qth.net>
Sent: Monday, March 29, 2010 10:04 AM
Subject: Re: [Elecraft] Bare Foot


> It's (at least was when I was still working) common to use heel straps as 
> part of ESD protection in industry.

Last time I saw heel straps in use was in the late 80s at a site that
builds solid fuel rocket motors for military and aerospace uses. They
also had testing equipment to check that your shoes really would
dissipate any static charge. When you are in a bay with a booster
containing 600,000lbs of fuel, static discharges are discouraged.


Mark  AD5SS



On Mon, Mar 29, 2010 at 9:42 AM, Wes Stewart <n7ws at yahoo.com> wrote:
> It's (at least was when I was still working) common to use heel straps as 
> part of ESD protection in industry. These were of similar material to 
> wrist straps and contacted the sweat layer inside the shoe on one end and 
> the floor on the other. The floor had to be treated with an ESD safe 
> coating, however. Likewise, ESD mats were only cleaned with an approved 
> cleaner and smocks that didn't generate static charges were worn over 
> street clothing.
>
> Modern linoleum (the real stuff) often has a coating on the surface which 
> is likely to be some kind of plastic and if you're using "linoleum" 
> generically, then you might have vinyl that is also plastic and 
> potentially an ESD generator, albeit probably not as bad as carpet.
>
> You will no doubt get an argument from some saying being connected to the 
> floor is an unsafe thing while working on things electrical. This is true 
> if you stand a chance of coming in contact with the A/C mains.
>
> That said, I use the bare foot technique sometimes, although the floors in 
> my house are brick and not plastic.
>
> Wes N7WS
>
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