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Hi all,
I frequent a large grocery market nearby and inevitably every time I
go there I get electrical shocks. I walk around with a cart and often
if I touch a metal fixture (fridge, mesh rack) I get a painful shock.
Sometimes I get a shock if I leave the cart for a few seconds and then
touch its metal mesh.

I was wondering what everyone thought. At first I thought it would be
ESD, but why would it be so extreme? It happens every time. I live in
a place that's pretty dry - RH goes under 20% regularly - and being on
a plain it has a lot of wind, which could create triboelectric
charging. But I'm not really sure about this.

I don't know which way the ESD happens. Is my body discharging into
the cart? Is the cart discharging into my body? Is my body discharging
into the racks or vice versa? How can one check the directionality of
ESD?

One theory about ESD I have is that the fixtures get charged and my
body gets the charge applied to it. This however isn't necessarily
true to me because eg today I got a painful shock from touching the
inside metal surface of a fridge, and that's supposed to be earthed.

Another theory is that as I walk around in the store, as I move around
with the cart, that charges my body. I wear rubber sandals and the
cart has rubber wheels. That would mean I'm a conductor, attached to a
large antenna (the cart's mesh frame), moving through dry air,
insulated from the ground. The ground is made out of some sort of high
impact ceramic-ish tile. But then why would my own cart shock me just
mere seconds after letting go of it? I was unloading my groceries for
the cashier.

My third theory is that this whole facility has a lifted earth
potential. There's an industrial area nearby and they may be dumping a
lot of current into earth which would create a situation where walking
on the ground charges you, and then touching something that's low-Z to
neutral discharges your body (in this case this would be the earthed
fridges etc).

I was wondering how people would approach diagnosing this problem, and
how you would fix it if you had the ability to change anything about
the facility at hand - more as a thought exercise, but if I figure out
what's going on I'm going to write to the company.

Thanks

On 5/4/2024 12:28 PM, cheater cheater wrote:

My third theory is that this whole facility has a lifted earth
potential.

I was wondering how people would approach diagnosing this problem, and
how you would fix it if you had the ability to change anything about
the facility at hand - more as a thought exercise, but if I figure out
what's going on I'm going to write to the company.

I would investigate that supermarket for proper facility grounding using my Biddle Megger Earth Tester, model 250260. I use it for testing radio station facilities where proper grounding can be vital. If the ground resistance is too high there are a number of techniques to reduce it, including specialized techniques for areas with particularly low soil conductivity.
--
Dale H. Cook, Retired AM/FM/TV Chief Engineer, Roanoke/Lynchburg, VA

I suggest a casual investigation to learn from the employees what they might be experiencing. Do not jump to conclusions with a solution or lead them. Just ask if they are experiencing electric shocks as they work in the store and see where it leads you. Your might discover something interesting.

If they are getting shocked, look for details:
Has anyone complained?
Is anyone concerned?
Has it always been this way?
Is it all day long?
Is it this way at other stores in the neighborhood?
How do you manage or mitigate the shocks?

It's been like this for at least a year (probably much longer) and the
staff and other patrons are experiencing shocks too.

No one gives a crap

It's any time of the day

There aren't any other stores in the neighrborhood. But I own a
storage room about 100m away and that has metal walls on a concrete
slab and those don't shock me.

I don't manage them at all. The best way I've found is to first touch
the metal fixtures using my knuckles, where shocks don't hurt. But
I'll often forget to do it.

On Sat, May 4, 2024 at 7:43?PM Clark Foley via groups.io
<clarkfoley@...> wrote:

I suggest a casual investigation to learn from the employees what they might be experiencing. Do not jump to conclusions with a solution or lead them. Just ask if they are experiencing electric shocks as they work in the store and see where it leads you. Your might discover something interesting.

If they are getting shocked, look for details:
Has anyone complained?
Is anyone concerned?
Has it always been this way?
Is it all day long?
Is it this way at other stores in the neighborhood?
How do you manage or mitigate the shocks?

I just wrote a reply that then disappeared. I've been seeing strange behavior since the recent "upgrades" were done in groups io. And WTH is "RSS feed?"

Ed

OK, I'll try to post again.

Try a simple experiment by wrapping a small damp rag around one of your shoes, and secure it with duct tape. Then wander around with the cart and see what happens. This can also be an ice breaker for conversations - but not with yourself. It will appear more interesting if you carry a clipboard and take notes.

Walking around on well insulated surfaces will tend to charge you up, while a discharge path should undo it. You could try barefoot too but that's probably frowned upon in stores.

Ed

There are anti-static heal straps available. Working with $200k CCD's I'd wear one all day just in case I might forget the wrist strap when coming back from the loo.

That is HEEL of course

I like the ideas about the anti static heel straps.

How can one check the direction of ESD? How to find out if it's me
being charged, or the furniture?

On Sat, May 4, 2024 at 9:11?PM Bruce Atwood via groups.io
<CCDman1@...> wrote:

There are anti-static heal straps available. Working with $200k CCD's I'd wear one all day just in case I might forget the wrist strap when coming back from the loo.

On Sat, May 4, 2024 at 11:31 AM, cheater cheater wrote:

I frequent a large grocery market nearby and inevitably every time I go there I get electrical shocks.

My first recommendation was that you try different shoes. I'd still try this, but if this is happening to everyone, I'd suspect the floor tiles. Some materials are more likely to generate triboelectric charge exchange.

We tend to think of "ground" as an absolute thing, but it's not, it's relative.

This has me wondering if that store has some sort of ion generator, intended or accidental, that's pumping out ions into the air. If that were the case, you might charge up faster than your cart if the cart wheels were more conductive than the soles of your shoes, or vice-versa.

--
Jim Adney
Madison, WI USA

what would make an "accidental" ion generator?

On Sun, May 5, 2024 at 12:16?AM Jim Adney via groups.io
<jadney@...> wrote:

On Sat, May 4, 2024 at 11:31 AM, cheater cheater wrote:

I frequent a large grocery market nearby and inevitably every time I go there I get electrical shocks.

My first recommendation was that you try different shoes. I'd still try this, but if this is happening to everyone, I'd suspect the floor tiles. Some materials are more likely to generate triboelectric charge exchange.

We tend to think of "ground" as an absolute thing, but it's not, it's relative.

This has me wondering if that store has some sort of ion generator, intended or accidental, that's pumping out ions into the air. If that were the case, you might charge up faster than your cart if the cart wheels were more conductive than the soles of your shoes, or vice-versa.

--
Jim Adney
Madison, WI USA

Interesting; last week I was at one of the Costcos I visit frequently, and I had the same experience (which has NEVER happened before, and I've been shopping there since the mid 80's).? The charge would build up very quickly (maybe 6-8 steps), then discharge between my hands/fingers and the plastic grip of the cart.? Most of the time it discharged while I was gripping it, not when I let go and re-grasped it.? It seemed like it was building up a charge until it could overcome cracks in the plastic or ???.? No discharges onto other metal surfaces.? Same old shoes/jeans etc.? Outside the store in the parking lot everything was normal.
-Dave

I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey

On Sat, May 4, 2024, 7:09 PM Dave Seiter via groups.io <d.seiter=
att.net@groups.io> wrote:

Interesting; last week I was at one of the Costcos I visit frequently,
and I had the same experience (which has NEVER happened before, and I've
been shopping there since the mid 80's). The charge would build up very
quickly (maybe 6-8 steps), then discharge between my hands/fingers and the
plastic grip of the cart. Most of the time it discharged while I was
gripping it, not when I let go and re-grasped it. It seemed like it was
building up a charge until it could overcome cracks in the plastic or ???.
No discharges onto other metal surfaces. Same old shoes/jeans etc.
Outside the store in the parking lot everything was normal.
-Dave
On Saturday, May 4, 2024 at 09:31:40 AM PDT, cheater cheater <
cheater00social@...> wrote:

Hi all,
I frequent a large grocery market nearby and inevitably every time I
go there I get electrical shocks. I walk around with a cart and often
if I touch a metal fixture (fridge, mesh rack) I get a painful shock.
Sometimes I get a shock if I leave the cart for a few seconds and then
touch its metal mesh.

I was wondering what everyone thought. At first I thought it would be
ESD, but why would it be so extreme? It happens every time. I live in
a place that's pretty dry - RH goes under 20% regularly - and being on
a plain it has a lot of wind, which could create triboelectric
charging. But I'm not really sure about this.

I don't know which way the ESD happens. Is my body discharging into
the cart? Is the cart discharging into my body? Is my body discharging
into the racks or vice versa? How can one check the directionality of
ESD?

One theory about ESD I have is that the fixtures get charged and my
body gets the charge applied to it. This however isn't necessarily
true to me because eg today I got a painful shock from touching the
inside metal surface of a fridge, and that's supposed to be earthed.

Another theory is that as I walk around in the store, as I move around
with the cart, that charges my body. I wear rubber sandals and the
cart has rubber wheels. That would mean I'm a conductor, attached to a
large antenna (the cart's mesh frame), moving through dry air,
insulated from the ground. The ground is made out of some sort of high
impact ceramic-ish tile. But then why would my own cart shock me just
mere seconds after letting go of it? I was unloading my groceries for
the cashier.

My third theory is that this whole facility has a lifted earth
potential. There's an industrial area nearby and they may be dumping a
lot of current into earth which would create a situation where walking
on the ground charges you, and then touching something that's low-Z to
neutral discharges your body (in this case this would be the earthed
fridges etc).

I was wondering how people would approach diagnosing this problem, and
how you would fix it if you had the ability to change anything about
the facility at hand - more as a thought exercise, but if I figure out
what's going on I'm going to write to the company.

Thanks

i did think of a chain. or one of those grounding strips you can put on cars.

On Sun, May 5, 2024 at 3:49?AM Dave Casey via groups.io
<polara413@...> wrote:

I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey

On Sat, May 4, 2024, 7:09 PM Dave Seiter via groups.io <d.seiter=
att.net@groups.io> wrote:

Interesting; last week I was at one of the Costcos I visit frequently,
and I had the same experience (which has NEVER happened before, and I've
been shopping there since the mid 80's). The charge would build up very
quickly (maybe 6-8 steps), then discharge between my hands/fingers and the
plastic grip of the cart. Most of the time it discharged while I was
gripping it, not when I let go and re-grasped it. It seemed like it was
building up a charge until it could overcome cracks in the plastic or ???.
No discharges onto other metal surfaces. Same old shoes/jeans etc.
Outside the store in the parking lot everything was normal.
-Dave
On Saturday, May 4, 2024 at 09:31:40 AM PDT, cheater cheater <
cheater00social@...> wrote:

Hi all,
I frequent a large grocery market nearby and inevitably every time I
go there I get electrical shocks. I walk around with a cart and often
if I touch a metal fixture (fridge, mesh rack) I get a painful shock.
Sometimes I get a shock if I leave the cart for a few seconds and then
touch its metal mesh.

I was wondering what everyone thought. At first I thought it would be
ESD, but why would it be so extreme? It happens every time. I live in
a place that's pretty dry - RH goes under 20% regularly - and being on
a plain it has a lot of wind, which could create triboelectric
charging. But I'm not really sure about this.

I don't know which way the ESD happens. Is my body discharging into
the cart? Is the cart discharging into my body? Is my body discharging
into the racks or vice versa? How can one check the directionality of
ESD?

One theory about ESD I have is that the fixtures get charged and my
body gets the charge applied to it. This however isn't necessarily
true to me because eg today I got a painful shock from touching the
inside metal surface of a fridge, and that's supposed to be earthed.

Another theory is that as I walk around in the store, as I move around
with the cart, that charges my body. I wear rubber sandals and the
cart has rubber wheels. That would mean I'm a conductor, attached to a
large antenna (the cart's mesh frame), moving through dry air,
insulated from the ground. The ground is made out of some sort of high
impact ceramic-ish tile. But then why would my own cart shock me just
mere seconds after letting go of it? I was unloading my groceries for
the cashier.

My third theory is that this whole facility has a lifted earth
potential. There's an industrial area nearby and they may be dumping a
lot of current into earth which would create a situation where walking
on the ground charges you, and then touching something that's low-Z to
neutral discharges your body (in this case this would be the earthed
fridges etc).

I was wondering how people would approach diagnosing this problem, and
how you would fix it if you had the ability to change anything about
the facility at hand - more as a thought exercise, but if I figure out
what's going on I'm going to write to the company.

Thanks

I think the problem comes from shopping carts with plastic tires instead of rubber. I had a small spark at a supermarket that had replaced their carts a few weeks earlier. The wheels have bright red polyurethane? tires. The problem will likely go away once the wheels get some dirt and scratches on them.

?? Bruce Gentry, KA2IVY

Same here, at the close by Walmart. If I hold the handle so I touch the metal I do not get the shocks. But let a gap form and Whammo! But not always, so cart differences, humidity differences?

Frank DuVal

I wonder if the companies installed an ion generator to purify the "air" due to the covid stuff?
...just? thought.....
搁别苍é别

Well, we have used ionizers at work to decrease the risk of ESD, so maybe they would have the opposite effect, 搁别苍é别?? ? ? ? ? ? Jim Ford?

Yahoo Mail: Search, Organize, Conquer

On Sat, May 4, 2024 at 11:06 PM, 搁别苍é别<k6fsb.1@...> wrote: I wonder if the companies installed an ion generator to purify the "air"
due to the covid stuff?
...just? thought.....
搁别苍é别

rubber wheels here, by the looks of it the carts are at least 10 years
old. so no, not polyurethane and not new.

anyways, does anyone know how to measure the direction of esd? some
sort of galvanometer?

On Sun, May 5, 2024 at 5:05?AM greenboxmaven via groups.io
<ka2ivy@...> wrote:

I think the problem comes from shopping carts with plastic tires instead
of rubber. I had a small spark at a supermarket that had replaced their
carts a few weeks earlier. The wheels have bright red polyurethane?
tires. The problem will likely go away once the wheels get some dirt and
scratches on them.

Bruce Gentry, KA2IVY

On 5/4/24 21:49, Dave Casey wrote:

I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey

On Sat, May 4, 2024, 7:09 PM Dave Seiter via groups.io <d.seiter=
att.net@groups.io> wrote:

Interesting; last week I was at one of the Costcos I visit frequently,
and I had the same experience (which has NEVER happened before, and I've
been shopping there since the mid 80's). The charge would build up very
quickly (maybe 6-8 steps), then discharge between my hands/fingers and the
plastic grip of the cart. Most of the time it discharged while I was
gripping it, not when I let go and re-grasped it. It seemed like it was
building up a charge until it could overcome cracks in the plastic or ???.
No discharges onto other metal surfaces. Same old shoes/jeans etc.
Outside the store in the parking lot everything was normal.
-Dave
On Saturday, May 4, 2024 at 09:31:40 AM PDT, cheater cheater <
cheater00social@...> wrote:

Hi all,
I frequent a large grocery market nearby and inevitably every time I
go there I get electrical shocks. I walk around with a cart and often
if I touch a metal fixture (fridge, mesh rack) I get a painful shock.
Sometimes I get a shock if I leave the cart for a few seconds and then
touch its metal mesh.

I was wondering what everyone thought. At first I thought it would be
ESD, but why would it be so extreme? It happens every time. I live in
a place that's pretty dry - RH goes under 20% regularly - and being on
a plain it has a lot of wind, which could create triboelectric
charging. But I'm not really sure about this.

I don't know which way the ESD happens. Is my body discharging into
the cart? Is the cart discharging into my body? Is my body discharging
into the racks or vice versa? How can one check the directionality of
ESD?

One theory about ESD I have is that the fixtures get charged and my
body gets the charge applied to it. This however isn't necessarily
true to me because eg today I got a painful shock from touching the
inside metal surface of a fridge, and that's supposed to be earthed.

Another theory is that as I walk around in the store, as I move around
with the cart, that charges my body. I wear rubber sandals and the
cart has rubber wheels. That would mean I'm a conductor, attached to a
large antenna (the cart's mesh frame), moving through dry air,
insulated from the ground. The ground is made out of some sort of high
impact ceramic-ish tile. But then why would my own cart shock me just
mere seconds after letting go of it? I was unloading my groceries for
the cashier.

My third theory is that this whole facility has a lifted earth
potential. There's an industrial area nearby and they may be dumping a
lot of current into earth which would create a situation where walking
on the ground charges you, and then touching something that's low-Z to
neutral discharges your body (in this case this would be the earthed
fridges etc).

I was wondering how people would approach diagnosing this problem, and
how you would fix it if you had the ability to change anything about
the facility at hand - more as a thought exercise, but if I figure out
what's going on I'm going to write to the company.

Thanks

My understanding of the “air sanitizers” is that there are at least two
types. One uses ultraviolet light. Shortwave UV (UV-C) will work to destroy
bacteria and viruses in the air, but some have the problem of generating
ozone. If they use a UV band at a certain range of wavelengths. the UV is
still antimicrobial but does not generate ozone. According to the vendors
of these systems, certain wavelengths will actually break down ozone. A
side effect of these is generating ions. Hospitals use UV light air
sanitizers in operating rooms. It would be very dangerous to allow static
charges to build up because of ions - sparks can ignite flammable
anesthetics. OR flooring is usually conductive for this reason.

Another system is an ion generator. You may have seen the “after a
rainstorm fresh air” stuff (though I think it needs lightning during a
storm for this). Because of problems with charged ions in the air (maybe
causing shocks?) there are bipolar ion generators.

Then there are the “loss control” systems - meaning anti-theft systems.
These use RF, but are generally localized to the store exits and I’ve not
seen them in supermarkets. These use those anti-theft tags on clothing and
stuck onto boxes. The RF fields are relatively limited to the area around
the exits.

The Amazon markets that have the system that lets you simply put things in
your shopping cart and then when you’re done just walk out - it’s called
“Just Walk Out”. My understanding of that system is that it uses multiple
video cameras, weight sensors, and an AI application that recognizes
products (and likely the shopper as well, but I think it may use an app on
your smartphone for that). But it does not use RF tags so far as I know and
no generalized RF fields as part of the system.

Shopping cart wheels may have, or are being, modified because some markets
have changed to anti-theft carts. Loss of shopping carts can be expensive,
so there are some available with a mechanism in the wheels and some sort of
sensor buried in the parking lot entrances/exits that will cause the wheels
to lock up if you try to leave the parking area with the cart.

I think static buildup is the likely cause. You could try taking a length
of metal chain, toss it in the lower part of the shopping cart and let one
end drag on the floor.

Steve H.

On Sun, May 5, 2024 at 03:52 Jim Ford via groups.io <james.ford=
cox.net@groups.io> wrote:

Well, we have used ionizers at work to decrease the risk of ESD, so maybe
they would have the opposite effect, 搁别苍é别? Jim Ford

Yahoo Mail: Search, Organize, Conquer

On Sat, May 4, 2024 at 11:06 PM, 搁别苍é别<k6fsb.1@...> wrote: I
wonder if the companies installed an ion generator to purify the "air"
due to the covid stuff?
...just thought.....
搁别苍é别

On 5/4/24 9:53 PM, Frank DuVal via groups.io wrote:

Same here, at the close by Walmart. If I hold the handle so I touch
the metal I do not get the shocks. But let a gap form and Whammo! But
not always, so cart differences, humidity differences?

Frank DuVal

On 5/4/2024 9:49 PM, Dave Casey wrote:

I too have dealt with shocks from the cart at my grocery store. I
attributed it to the cart building up charge by rolling. A good test
might
be to hang a dragging chain from the cart, but I've never bothered.

Dave Casey