So, to add another advice, be sure that you have a ground fault circuit interrupter or residual-current device and test it regularly.
If you receive a shock, if can affect the rhythm of your heart and cause problems later. We’re taught to go and get an ECG after receiving a shock. Like jump in the car and go to the doctor or hospital and have someone else drive you. If you’ve received a shock - go get checked out.
Your heart muscle is controlled by a tiny voltage. Suddenly forcing it to follow 50/60Hz of a huge voltage isn't precisely natural, and something that can leave lasting damage even if your heart seems to work just fine immidiately after.
There is a reason in electrics a lot is done just to prevent electrical shocks (e.g. RCDs), because you know: it kills people.
I am legally allowed to connect houses to the electrical grid in Germany.
That was an electrical shock that in my naive opinion does not pose a cardiac risk.
I imagine that there is some judgement call to make about what is "electrical shock", and when does it pose a cardiac risk.
If all is going well, shocks are rare, and so I could imagine as a rule "if you felt a shock, go to the doctor". But in some [yes, of course, unfortunate, avoidable, and unacceptable] contexts, a rule like that might not be followed. That is why I was wondering about what guidance electrician's unions provide.
"basic respect for human life" and "unions" can have a lot in common, especially in such a country.
That's common in the way shark bites and lightening strikes are common. Dropping dead hours after a minor electrical shock is so rare you shouldn't even be worrying about it.
>You should always see a cardiologist even if you feel completely fine.
It was included in your training so the company could cover its ass. By including a comically over the top warning and recommendation like that they are ensuring that statistically nobody will follow the training and the company will have leverage if you get hurt on their watch and sue.
It's a really shame that this kind of disingenuous ass covering behavior gets picked up and parroted by people as though it were honest advice because it moves the overton window and leads to a world where everyone acts like step-stools are a serious threat to public health.
Everybody follows the training, because you get fired if you don't, or your manager gets fired. I don't know where you live, but here we have unions that make sure workers are as safe as reasonably possible.
A very good summary article is here: https://www.bmj.com/content/357/bmj.j1418 .
Take home points:
-- Arrhythmias (superventricular and ventricular) are common
-- Exposure to high voltage can cause asystole directly
-- Delayed [life threatening!] ventricular arrhythmias have been reported for up to 12 hours post incident, both with high and low voltage shocks
-- Delayed, serious bradycardia can result months or years after the accident
-- The SA nodes are particularly vulnerable; patients may effectively give themselves an SA node ablation
-- Direct myocardial injury may occur without chest pain (due to nerve damage)
-- MI may also occur via coronary spasm or thrombus.
That neglects the rest of the body -- where the effects can also be significant.
Electricity in large amounts is bad for you – c.f. the electric chair!
Yep. This is what defibrillation is. When you use a defibrillator, you're shocking the heart into asystole in the hopes that it will restart itself. Shocking an already "flatlined" heart will not restart it, contrary to what many movies would have you believe.
> The SA nodes are particularly vulnerable; patients may effectively give themselves an SA node ablation
This I did not know. Wow!
For normal household circuits I’d just say learn from your mistake.
Think of it as an inverse lottery you really really don't want to lose. The outcome, not the odds is what matters in this case.
The Alanis Morissette method; I've got one hand in my pocket, and the other's probing a live circuit.
I mean, we're talking about an organ that runs off of millivolts. Surely the heart is close enough to the middle when we're talking about running 120 or 240 volts of AC through it?
IIRC they were rated at 600v, and would leave black indents in the skin.
Kids are effing stupid…
You'll get a nice, painful reminder to respect electricity that'll last a few days, and not be in any actual danger.
(I also did the exact same thing as a teenager)
Seriously thought electrolytic capacitors need to be respected but not feared.
Knowing that they could deliver a nasty shock, I discharged one once by shorting the terminals with a screw driver.
The sound of the spark, and the scorch mark left on the PCB and screw driver left me fearful of them.
Or was that caused by the knowledge that I had a friend who said he put one of those capacitors in a highlighter, thereby making a makeshift, single-use, "shelf-unstable" taser?
it's also interesting to witness a bit glass thing acting like a capacitor
ps: for long I wanted to make a discharge rod but never finished it
The very first capacitors were glass jars:
In a power supply, you'd also have to worry about shorting and shocking other ICs with steel wool, but not with a big capacitor.
But that didn't stop him from encouraging me to experiment while taking precautions. As a teenager I destroyed two ATX PSUs trying to add 110vac compatibility to an 12vdc RC battery charger. Third time was the charm.
Even after that, I continued to do dumb things around electricity. I'm not all that smart.
Additionally there are typically bleed resistors to drain capacitors to safe levels, but they can also go open.
They're inexpensive for desktop/gaming machines and if there's a fault its either in warranty or its time to purchase a new one.
i repeat danger
There are components in there that can exceed mains voltage when probed the wrong way.
When you start getting into the higher voltages, the body’s resistance is much lower. It only takes a few milliamps to stop the heart.
Not in a normal power supply.
Sure it's peak rather than RMS, but a warning that something "exceeds mains voltage" to me sounds like a description of a significantly bigger danger than that.
Is it to discharge that capacitors?
- Always ground yourself to an actual building rod or a rod planted at least six feet deep.
- Lock out, tag out everything. Our tools were metal, go work on ONE truck with a battery array without an extension and you will almost certainly arc something.
- Voltage isn't what kills. It takes an insanely low amount of amperage to stop a heart.
- Always have another person nearby with a wood or rubberized object to disconnect the circuit. Being stuck being electrocuted is a surprisingly slow death that you will be entirely conscious for.
https://www.youtube.com/watch?v=CyKHVl3xF70
Personally I would probably not want to mess around inside a AXT supply.
But dielectric soakage runs in reverse, too. So even if you short out the capacitor once, it can recover some voltage after days to months left open again. (The energy comes from the molecules in the dielectric relaxing, very slowly.)
This isn't a problem if the designer has put in a bleeder resistor across the capacitor. But some designers are cheap, and don't want to pay the extra few cents to make their products non-lethal to technicians. Some are just stupid (yes, dumbfuck "senior engineer" coworker, I am thinking of you here, you colossal waste of oxygen).
What you want to do is short it out, with a screwdriver or otherwise, then keep it shorted with a gator cable or even resistor. Then you'll be safe even if you set the project aside for a week. Or three months.
I wired up an unwisely huge bank out of them for some fun HV experiments. They were in a shed outside and could self charge to useful levels in the course of a windy day. Dont recall the actual numbers but it could vaporize dimes handily.
Mains filter caps will be lucky to recover a few dozen volts, which isn't going to do much (and inside a PSU, if the voltage is high enough it will try to run and quickly discharge them anyway.)
Maybe I'm just salty about having had this argument too often recently. But I strongly believe that every mains voltage or higher system needs bleeders across its capacitors. If you don't want to pay for the resistor, fine... but leave the footprint for it.
This goes 10x stronger if the thing is open-frame, sits on a bench, and is regularly being probed by engineers. Just put the goddamn resistors in there before someone gets hurt.
Ahem. Apologies for the intermission.
Check for voltage - If not present / marginal, Then shorten, Else discharge through resistor and GoTo Check. A "capacitor discharge tool" automates this cycle.
In most other parts of the computer the worst that can happen in most cases is that you damage the computer, the power supply is different, there you also have a good chance of getting shocked.