Electrical Shock Log Book

[PRR]

> 38VAC last week (measured it after), touched my sink and my dishwasher at the same time.

I do not know Denmark. But generally, all touchable metal "must" be bonded together. This means the dishwasher and the sink/plumbing should both connect to building ground bus. The dishwasher may have a 3-pin plug or 3-wire cable with grounding. (I am aware that some places do not require grounds on all loads.) The water plumbing "should" have a jumper wire to the electrical service. This has become dubious with the increased use of plastic water pipe. In my house I am nearly ALL plastic pipe, so you can't get a shock from the sink. In my last house my inside pipes were bonded to the pipe from the street-- but later I found out the metal pipe in the wall transitioned to plastic pipe a few inches out in the dirt.

> My sink and water kettle also have 60V between them! Past two years... Note to call the landlord.

In the USA (120V) a 60V voltage more-often suggests the kettle has more-or-less leakage but equally to BOTH live wires. If the kettle is 2-pin, it can't pull itself to ground. On such appliances, the idea is that the internal insulation "will not leak enough" to be a danger to people. It may still leak enough to show on a high-impedance meter. Try shunting 100K between them and measure again. (100K is the high end of typical human skin resistance.) If the volts are now just-a-few, then leakage is very small and not a danger. If it is stubbornly 60V, get rid of that kettle!

 

[jasonallenh]

2004 - My mother was indirectly hit by lightning while closing a metal door behind her (she felt the 'tingle' before the bolt, so she was trying to shut the door behind her). It threw her about six feet across the room, she landed in a pile of garage junk, and took the dog with her. She may have suffered a concussion (no health care here......) but her and the dog made a full recovery. Florida is NOTORIOUSLY dangerous when it comes to lightning.

Presently, I can't come close to that... last month I got some 120 AC on the front panel of some Mackie mixer in a house with grounding issues. it turns out there was an arc in the mains outlet. minor shock, but enough to shock the next guy over through me 

 

[abbey road d enfer]

> 38VAC last week (measured it after), touched my sink and my dishwasher at the same time.

I do not know Denmark. But generally, all touchable metal "must" be bonded together.

I don't know much either, but it appears that, because of the rocky nature of soil there, "earth potential" has just about meaning as "teenager wisdom". As a result, in many houses, the wall sockets' earth tag is connected to neutral, which apparently leads to many errors and results in live apparatus.

 

[JohnRoberts]

> 38VAC last week (measured it after), touched my sink and my dishwasher at the same time.

I do not know Denmark. But generally, all touchable metal "must" be bonded together. This means the dishwasher and the sink/plumbing should both connect to building ground bus. The dishwasher may have a 3-pin plug or 3-wire cable with grounding. (I am aware that some places do not require grounds on all loads.) The water plumbing "should" have a jumper wire to the electrical service. This has become dubious with the increased use of plastic water pipe. In my house I am nearly ALL plastic pipe, so you can't get a shock from the sink. In my last house my inside pipes were bonded to the pipe from the street-- but later I found out the metal pipe in the wall transitioned to plastic pipe a few inches out in the dirt.

i just installed a new dishwasher (my old one died a noisy grinding-sound death). It turns out that it was not grounded, so I grounded the new power connection, while the outlet it plugs into is still ungrounded. (I need to fix that too). 

While researching before the installation I found one news item about a man electrocuted when his wedding ring touched a hot wire... I suspect the ring might have helped only slightly. Another benefit to staying single I guess.

> My sink and water kettle also have 60V between them! Past two years... Note to call the landlord.

In the USA (120V) a 60V voltage more-often suggests the kettle has more-or-less leakage but equally to BOTH live wires. If the kettle is 2-pin, it can't pull itself to ground. On such appliances, the idea is that the internal insulation "will not leak enough" to be a danger to people. It may still leak enough to show on a high-impedance meter. Try shunting 100K between them and measure again. (100K is the high end of typical human skin resistance.) If the volts are now just-a-few, then leakage is very small and not a danger. If it is stubbornly 60V, get rid of that kettle!

+1 to high impedance leakage...  My house is old 2 wire branch wiring, but I installed GFCI outlets in the kitchen and bathroom. When plugging grounded outlet strips into the GFCI outlet, with it's ground floating. The leakage from multiple appliances can accumulate in the common ground lead.  I measured several tens of volts but only hundreds of uA between that floating ground and my metal kitchen sink. I'm not sure where my sink gets it's ground (there's a lot of iron in my tap water).

I could actually feel the hundreds if uA  at tens of volts as a very slight tingle, not at all painful but i reflexively pulled away JIC a stronger shock was possible.  I notice some similar high impedance leakage in a metal shelf on my workbench that has an LED light fixture mounted to it. UL generally looks the other way if leakage is < low single digit mA.

JR

 

[PRR]

> because of the rocky nature of soil there, "earth potential" has just about meaning as....

Different issue.

Connecting to dirt is wise, if the dirt will conduct. Here also, I can't get any solid connection to "Earth", only to thin soil.

However all metal in and around the house should be connected together. Zero Ohms between sink and dishwasher. That may not be required in a land where to-dirt shocks don't happen and "grounding" is treated casually, but still a Good Idea.

 

[joaquins]

Once I measured about 80V AC between the desk and the audio equipment in the disco I was working, after few hours working on that I found one of the ground wires going from outlet box to outlet box under the desk was open, so the ground was floating with few meters together with the other two lives by the side, maybe induction or capacitive coupling made it to go about 80V (at 220V mains) and was not pleasant to touch. Maybe you with 110V mains are in a similar situation, check the continuity over all the outlets to the PE.

JS

 

[PRR]

> UL generally looks the other way if leakage is < low single digit mA.

 

[abbey road d enfer]

> because of the rocky nature of soil there, "earth potential" has just about meaning as....

Different issue.

Why a different issue?
Because the "earth" there is not conductive enough, TT mode cannot be optimally implemented. Therefore TN is used, but the wiring in many parts of the country does not exist for TN-S, so they implement TN-C. Then in normal TN-C, the house wiring should be 3-wire, with N being distributed on two separate wires as N and T. Many old houses do not have 3-wire cabling, so the Danish government allowed using the 2-wire cabling and distributing N at the wall socket. It is not unknown to have two apparatus connected to two different wall sockets, one of them miswired, showing full voltage between chassis. Many people who are not aware of the difference between N and L would wire the T pin to anyone of the others.
This is quite surprising, knowing the Danish used to have the strictest electrical safety regulations in western Europe.

 

[0dbfs]

> My sink and water kettle also have 60V between them! Past two years... Note to call the landlord.

In the USA (120V) a 60V voltage more-often suggests the kettle has more-or-less leakage but equally to BOTH live wires. If the kettle is 2-pin, it can't pull itself to ground. On such appliances, the idea is that the internal insulation "will not leak enough" to be a danger to people. It may still leak enough to show on a high-impedance meter. Try shunting 100K between them and measure again. (100K is the high end of typical human skin resistance.) If the volts are now just-a-few, then leakage is very small and not a danger. If it is stubbornly 60V, get rid of that kettle!

It definitely shocked me. I'll try bridging with 100k and remeasuring.

The kettle is plugged into a power-strip where other items are also plugged in so it could be something else. Like the toaster, the fridge, etc... The fridge is plugged into the second socket on the wall outlet while the power-strip is connected to the first.

The house is a mix of 2-wire and 3-wire (different house from last time around) and the main breaker panel is a combination of boxes - old school screw-in fuses, shotgun-shell-fuses, etc....

"Hairy-and-Scary" are two terms I would use together to summarize.

Cheers,
jb

 

[JohnRoberts]

> My sink and water kettle also have 60V between them! Past two years... Note to call the landlord.

In the USA (120V) a 60V voltage more-often suggests the kettle has more-or-less leakage but equally to BOTH live wires. If the kettle is 2-pin, it can't pull itself to ground. On such appliances, the idea is that the internal insulation "will not leak enough" to be a danger to people. It may still leak enough to show on a high-impedance meter. Try shunting 100K between them and measure again. (100K is the high end of typical human skin resistance.) If the volts are now just-a-few, then leakage is very small and not a danger. If it is stubbornly 60V, get rid of that kettle!

It definitely shocked me. I'll try bridging with 100k and remeasuring.

The kettle is plugged into a power-strip where other items are also plugged in so it could be something else. Like the toaster, the fridge, etc... The fridge is plugged into the second socket on the wall outlet while the power-strip is connected to the first.

The house is a mix of 2-wire and 3-wire (different house from last time around) and the main breaker panel is a combination of boxes - old school screw-in fuses, shotgun-shell-fuses, etc....

"Hairy-and-Scary" are two terms I would use together to summarize.

Cheers,
jb

That sounds a little like my house... and why I added a few GFCI outlets in key areas. My kitchen has one of those GFCI outlets.  (I also bought a new kettle with lower leakage).

We can feel a shock from pretty small currents and of course your wouldn't want to drop a kettle full of boiling water... as long as the current is low enough that you don't get stuck to it, you will generally be uninjured. It takes more than 5 mA to get you stuck.

JR

 

[bitman]

JCM800 50watt.

Trying to make it mo betta.
Touched something I shoundta.

Every day in the dry environment of the rocky mountain winter. 2000000000000 kv of static just trying to do anything on or from corduroy couches.

It's enough static to shock one another through glass and ceramic while taking a coffee cup from a loved one for to get her a refill. - didn't they use that for insulators?

Dev pc laptop still rocking on nevertheless.......

 

[JohnRoberts]

> UL generally looks the other way if leakage is < low single digit mA.

I just let my fingers do some walking and did not find any hard single number for ground current leakage, I could imagine it being that low for handheld kitchen appliances.  Medical devices are extremely low leakage too.

They are more specific about ground bonding, or how the ground in 3 wire products act with tens of amps (they spec how much voltage rise or series resistance is acceptable, but ground bonding also tests current carrying capability (small PCB traces will usually be vaporized by ground bond testing).

I did see some leakage spec mentions (by hi-pot equipment makers) as high a 3,5mA but that seems high to me. Hi-pot testing also scales the current leakage for elevated test voltage so a 10mA hi-pot threshold might be 2 mA leakage at normal mains voltages.

The spec for GFCI outlets to trip is 5mA +/-1mA (not measured in the ground, but detected as not returning to neutral from the line), It wouldn't take too many 3.5mA line cord ground leaks to trip a GFCI, while that does happen sometimes (probably from marginal faulty products).

JR

 

[CJ]

'shocked again,  5:08 PM, Monday, just a knuckler, no bleeder on this Alamo Jet, no power or preamp tubes plugged in, just the 5Y3, only 170 V-dc as natural bleed-off saved the day,

weird amp , looks like is was made out of parts from a failing radio industry, 

 

[pucho812]

does taking a wiz on the electric fence as a kid count or is this just when we do gear?

 

[JohnRoberts]

does taking a wiz on the electric fence as a kid count or is this just when we do gear?

Reports vary** about whether this would actually cause a shock... While urine is conductive when a stream of  droplets have air gaps, there is no completed circuit... If the voltage was higher it should work, so don't pee on a high voltage distribution line. (as if you could reach  ;D )

JR

** I think mythbusters did a segment about this.

 

[joaquins]

does taking a wiz on the electric fence as a kid count or is this just when we do gear?

Reports vary** about whether this would actually cause a shock... While urine is conductive when a stream of  droplets have air gaps, there is no completed circuit... If the voltage was higher it should work, so don't pee on a high voltage distribution line. (as if you could reach  ;D )

JR

** I think mythbusters did a segment about this.

They did and IIRC they got it to work if you would be doing so in your knees to a subway rail, poor buster got shocked at the end of the day... Season two IIRC.

JS

 

[CJ]

reminds me of the electric piss pot, doing some late night activities at the local morgue because that's how we roll, this dude pisses on one of those flood lamps that gets pointed up at a cross or something like that, hi wattage, hot glass, piss broke the glass, dude keeps pissin, back plate fills up and starts to boiling while displaying all kinds of colors, red, green blue, gurgling away, must not have smelled that good, thus was born the electric piss pot,

 

[clintrubber]

Nice thread! 


Somewhere 199*: 

London City  (4) EL34 amp  (Dutch Marshall clone)
Bought prior to holidays, had to service it, went several weeks on holidays,
return from holidays, unplugged amp still manages to zap me...
(so no need for cap-replacement... )


Somewhere 199*:

SWR SM-400 stereo-amp in bridge mode.
SWR-supplied speaker cable: banana at amp side (OK!),  but big Switchcraft metal jack-plug (Bad Idea!).

Hold bass-strings with one hand, touch that big metal plug-sleeve with other hand,
some signal gets amplified, so big ('negative') signal polarity on that Switchcraft-sleeve, ouch!

 

[joaquins]

Nice thread! 


Somewhere 199*: 

London City  (4) EL34 amp  (Dutch Marshall clone)
Bought prior to holidays, had to service it, went several weeks on holidays,
return from holidays, unplugged amp still manages to zap me...
(so no need for cap-replacement... )


Somewhere 199*:

SWR SM-400 stereo-amp in bridge mode.
SWR-supplied speaker cable: banana at amp side (OK!),  but big Switchcraft metal jack-plug (Bad Idea!).

Hold bass-strings with one hand, touch that big metal plug-sleeve with other hand,
some signal gets amplified, so big ('negative') signal polarity on that Switchcraft-sleeve, ouch!

400W into 8Ω should be about 56VRMS, in bridging 23VRMS to ground. How big was the "ouch!"??

JS

 

[CJ]

Fri, 4:49 PM, 175 V-dc, residual cap voltage, new amp chassis, no bleeders yet, across the heart, sweaty hands, no big,