Why oh why.... TM auction fail.

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DarthKermit

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#1734357 10-Mar-2017 13:08

I've had a few zaps from 230 volts over the years. I'm probably damned lucky to still be alive. Several people a year on average die from electric shocks of no more than 230 volts.

Rikkitic

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#1734371 10-Mar-2017 13:27

I have been zapped too, but it is unlikely to kill you unless it passes through your heart. An old repairman's trick is to keep one hand in your pocket while testing voltages. Of course that only helps if you are not standing in water.

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RUKI

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#1734388 10-Mar-2017 14:23

Rikkitic:

I have been zapped too, but it is unlikely to kill you unless it passes through your heart. An old repairman's trick is to keep one hand in your pocket while testing voltages. Of course that only helps if you are not standing in water.

Concrete floor (e.g. in the garage) is electricity-conductive. Hence touching with one hand is not a good idea.

If you see sparkles in people's eyes - chances are - they have been electrocuted at some stage in life :-)

GGJohnstone

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#1734621 11-Mar-2017 00:04

Cowardice works well and enhances caution dealing with dangerous voltages.

Static electricity is correctly named; static. It can't hurt until it moves. So if you carelessly slid out of the car seat and you can feel the hair standing up on your head. Don't ground yourself to your opposite voltage . Close the car door pushing the glass and then you can charge off down the foot path. Loosing power as you go.

Will you and the car have to zero together or could you approach ground potential and leave the car charged up as an alarm or dog repellent?

The auction goods have been badly handled but it would take a bit of bad luck for a release of energy from the materials in the carpet interacting with themselves and the goods movement to deliberately break a delicate junction. It would be disappointing as well because you would have no smoke and flames.

nunz

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#1734753 11-Mar-2017 13:03

gzt:
tchart:

Just to play devils advocate here but when last did anyone kill a PC component through static electricity?

'kill' is an obvious outcome. Doesn't work? Easy. It's not the only possible outcome.

Static's not the only issue - how about the dust, finger acid, grease and other additives now in place.I would be expecting a power short unless dust blown out.

My wife asked if I was in pain when I saw the photo of the CPU. My poker face failed.

Image result for omg

nunz

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#1734756 11-Mar-2017 13:16

Rikkitic:

I have done that kind of thing for most of my long life and I am still here. I don't claim special knowledge, but I do think there is a slight obsession with risk in this country. You can also get hit by a bus crossing the street. Some risks are serious enough to be worth avoiding, others, though not impossible, are highly unlikely. What is the actual risk of a PSU developing a failure that would put deadly voltage on the case (impossible, I would think, with that big fat earth plug always present) or on one of the low voltage circuits (would most likely make itself well-known with fizzing, popping, acrid smoke, all kinds of other alarming things that might cause most people to think maybe I shouldn't replace the RAM right now). There needs to be some perspective on this.

I've always unplugged the pc, pushed power button in to discharge residuals then made sure the casing of the pc and I are in contact at all times and whatever I'm working with is on the same mat as the pc. It's not failed me in 15 years- and the time it failed me was when I was lazy, turned off the plug and missed, turning off the wrong plug. Pulling the power cord out of the rear - always guaranteed to work

The chassis should be the best earth for the device and staying connected to it should keep you at the same charge as it is.

What has failed me is dust - like carpet dust / internal case dust, falling into something like a ram slot, ram put in, pc turned on and sizzle. I'm extremely picky now that I blow out, vacuum and keep clean the case and all parts of bench being worked on. That advert had me reaching for an air can.

As for risk - putting a hand in my pocket while working with voltage .. brrrrrrrrr!!!! Gonads and electricity - not a good combination.

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Rikkitic

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#1734786 11-Mar-2017 13:58

I was mainly responding to what I see as a slightly hysterical fear of mains electricity by people who have only ever had experience of batteries. Of course higher voltages need to be treated with appropriate caution but electricity isn't hiding behind a corner waiting to jump out at you. Whenever I have worked around mains voltages I have always taken suitable precautions. These include a non-conductive floor surface and other common-sense measures. One-handed probing is something that actually was advised (how seriously, I do not know) in the days when the inside of a TV was in fact a very dangerous place. Having your feet insulated doesn't help much if you create a circuit through both arms. Yet the TV usually had to be powered to check for faults. How else are you supposed to do it?

Isolation transformers are essential in my opinion when working with equipment outdoors or in dangerous environments. In a proper workshop I have never seen the need. What are you trying to isolate yourself from? In most cases it is the risk of a conducting piece of the equipment becoming live and you providing a circuit to earth through your feet. In a proper workshop environment this shouldn't happen anyway. It should not be possible to come into accidental contact with an earth except from the device you are working on. If the device has to be powered up to diagnose it, some parts of it will be live, other parts will offer a return path. An isolation transformer in this case does not offer any added protection. It is just gets in the way.

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sir1963

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#1734828 11-Mar-2017 15:50

Rikkitic:

I was mainly responding to what I see as a slightly hysterical fear of mains electricity by people who have only ever had experience of batteries. Of course higher voltages need to be treated with appropriate caution but electricity isn't hiding behind a corner waiting to jump out at you. Whenever I have worked around mains voltages I have always taken suitable precautions. These include a non-conductive floor surface and other common-sense measures. One-handed probing is something that actually was advised (how seriously, I do not know) in the days when the inside of a TV was in fact a very dangerous place. Having your feet insulated doesn't help much if you create a circuit through both arms. Yet the TV usually had to be powered to check for faults. How else are you supposed to do it?

Isolation transformers are essential in my opinion when working with equipment outdoors or in dangerous environments. In a proper workshop I have never seen the need. What are you trying to isolate yourself from? In most cases it is the risk of a conducting piece of the equipment becoming live and you providing a circuit to earth through your feet. In a proper workshop environment this shouldn't happen anyway. It should not be possible to come into accidental contact with an earth except from the device you are working on. If the device has to be powered up to diagnose it, some parts of it will be live, other parts will offer a return path. An isolation transformer in this case does not offer any added protection. It is just gets in the way.

Actually an isolating transformer is very useful , use it one all the time.

Not just for safety, but it allows you to clip a 'scope probe onto parts of a circuit you could not without unless you have a battery powered scope

however it is still safest to float the equipment under test.

nunz

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#1770827 26-Apr-2017 18:05

sir1963:

mclean:

Rikkitic: I have done that kind of thing for most of my long life and I am still here. I don't claim special knowledge, but I do think there is a slight obsession with risk in this country. You can also get hit by a bus crossing the street.

I agree about the obsession thing. In many ways electricity is more dangerous than a bus (unless you are deaf and blind). The thing is you are always given a simple way to isolate electrical equipment - the rules require it. The simple way to isolate a plug-in appliance it is to pull out the plug.

Have you ever tried fixing anything electronic ?

When unplugged the power supplies all read 0V, wonder if its a power supply fault....what do I do....

Unless it was a CRT monitor - those beasts held charge for long times and could rebuild charge after being discharged - and were deadly.

Rikkitic

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#1770836 26-Apr-2017 18:41

Thanks to my dad I spent (part of) my childhood playing with old radios, TVs, surplus transmitters, and other electronic devices of the 1950s. This was the era of vacuum tubes, all of which required anode supplies in the hundreds of volts, not to mention those grand old televisions with their enormous CRTs and the 20,000-volt horizontal oscillators that drove them. I remember the static electricity they produced, which I could feel on my arm from across the room. They were fun playthings and great learning devices, long before solid-state and batteries, which in those days were only useful for torches. I used to enjoy charging up the big capacitors and making them pop. Tons of fun for a curious 10 year-old.

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