If you touch just one phase.. - Page 3 - Electronic Circuits Projects Diagrams Free

Pommie · 5th July 2009, 05:08 PM

Quote:

Originally Posted by Hero999

Did the apprentice get manslaughter?

No, he followed the rules. He came upon a situation where the lift wasn't working. My Friend was old school, he had placed his jacket over the isolator - current rules state he should have locked it off. The system he was working on had no way to lock it. The apprentice simply turned it back on - if anyone was working on it then it would be locked off.

Now, if you follow the rules, you would not work on it until it was capable of being locked off. I'll bet it still happens everyday.

Mike

whiz115 · 5th July 2009, 07:35 PM

Quote:

Originally Posted by Hero999

I
When you mean electrocuted do you mean killed or just a bad shock?

ok wrong expression... i mean they got a shock

@KMoffett so concerning HV you don't need to touch something grounded?!
about stun guns indeed they got two contact probes.. i didn't remembered that.

hmmm but still i don't get it... how about the screwdrivers that thest the mains? how do they work?! they don't need you touch a ground!

KMoffett · 5th July 2009, 08:42 PM

I've taken two good hits, 20 years apart, hand to hand. One from a 400CTVAC secondary in an o-scope supply that got shorted to the case. The other was a prototype piece of medical equipment that a salesman sneaked into our OR, without a safety check, to demo. Set off the LIM alarms. When I got it to the shop I started to plug it into the leakage analyzer. One hand on the device's case and as I plugged it in, my other hand touched the analyzer's case. Whoever wired the device swapped the hot and ground. The case was hot to the tune of 120VAC. Both times I was knocked across a room, gasping, trying to breathe.

One hand in your pocket!...one hand in your pocket!...one hand in your pocket!...and lest you have forgotten...ONE HAND IN YOUR POCKET!...

ken

KMoffett · 5th July 2009, 09:03 PM

Quote:

Originally Posted by whiz115

how about the screwdrivers that thest the mains? how do they work?! they don't need you touch a ground!

I have not used one...but I suspect that they are using a neon lamp (like a NE2), and a safety current-limiting resistor. These require >90 volts to fire, but only a current in the µA range to remain lit. At line frequencies, the even the small capacitive coupling of your insulated body to the grounded electrical environment near you is enough to pass this much current. This level of current is undetectable (by you) and considered safe, even a direct patient contact medical environment.

Ken

Hero999 · 5th July 2009, 09:31 PM

Quote:

Originally Posted by KMoffett

One from a 400CTVAC secondary in an o-scope supply that got shorted to the case.

That's why you should never remove the earth on an oscilloscope.

KMoffett · 5th July 2009, 10:26 PM

That was in the days of the low-end, ungrounded power-cord scopes...Heathkit...Eico.... But that scope was one I actually was building from scratch. Since I didn't have another suitable transformer, I decided to buy a scope kit. :0

Ken

tcmtech · 5th July 2009, 10:40 PM

It must depend on your personal resistance and tolerance to shock.
I have taken a direct hits off of 5 - 12 KV 30 Ma neon sign transformers (2.5 - 6 KV from CT to output) to many times to care to mention.

480 volt hurts but rarely anything under that doesn't seem to cause me much lingering discomfort.

Automotive and farm equipment ignitions and antique magnetos also have given me to many shocks to count.

My Tesla coils and static generators put out voltages into the high 10's of KV to low 100's Of KV. I have no problem getting shocked by them either.

Hero999 · 6th July 2009, 06:31 PM

30mA is quite nasty but unlikely to kill, especially if it's a high frequency converter.

Tesla coils won't normally kill you but can give nasty RF burns. You can get killed from a Tesla coil, if the spark can connects you to the low-voltage high-current driver.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar
Title	Starter	Forum	Replies	Latest
Phase shift - Phase Angle	windozeuser	General Electronics Chat	20	20th March 2009 10:39 AM
Phase Sequence or Phase Present	neelam29	General Electronics Chat	7	23rd May 2007 11:25 AM
Three Phase Versus Single Phase For EV	fzn10	General Electronics Chat	4	31st July 2006 09:39 AM
3 phase to single phase	eyeofthefly	Electronic Projects Design/Ideas/Reviews	34	14th November 2003 04:17 PM
converting 3 phase motor to single phase	norberto fines	Electronic Projects Design/Ideas/Reviews	6	2nd September 2003 11:21 PM

5th July 2009, 08:42 PM	#33
KMoffett	I've taken two good hits, 20 years apart, hand to hand. One from a 400CTVAC secondary in an o-scope supply that got shorted to the case. The other was a prototype piece of medical equipment that a salesman sneaked into our OR, without a safety check, to demo. Set off the LIM alarms. When I got it to the shop I started to plug it into the leakage analyzer. One hand on the device's case and as I plugged it in, my other hand touched the analyzer's case. Whoever wired the device swapped the hot and ground. The case was hot to the tune of 120VAC. Both times I was knocked across a room, gasping, trying to breathe. One hand in your pocket!...one hand in your pocket!...one hand in your pocket!...and lest you have forgotten...ONE HAND IN YOUR POCKET!... ken __________________ "To invent, you need a good imagination and a pile of junk." Thomas A. Edison (1847 - 1931)

5th July 2009, 10:26 PM	#36
KMoffett	That was in the days of the low-end, ungrounded power-cord scopes...Heathkit...Eico.... But that scope was one I actually was building from scratch. Since I didn't have another suitable transformer, I decided to buy a scope kit. :0 Ken __________________ "To invent, you need a good imagination and a pile of junk." Thomas A. Edison (1847 - 1931)

5th July 2009, 10:40 PM	#37
tcmtech	It must depend on your personal resistance and tolerance to shock. I have taken a direct hits off of 5 - 12 KV 30 Ma neon sign transformers (2.5 - 6 KV from CT to output) to many times to care to mention. 480 volt hurts but rarely anything under that doesn't seem to cause me much lingering discomfort. Automotive and farm equipment ignitions and antique magnetos also have given me to many shocks to count. My Tesla coils and static generators put out voltages into the high 10's of KV to low 100's Of KV. I have no problem getting shocked by them either. __________________ "Issue a general safety warning. Then look the other way and allow stupidity the chance to eliminate itself." -- tcmtech "Those who can, Will. Those who can't, will achieve positions of power over those who can and then promptly stop them." -- tcmtech "Your impossibility may just be my day to day routine." -- tcmtech

6th July 2009, 06:31 PM	#38
Hero999	30mA is quite nasty but unlikely to kill, especially if it's a high frequency converter. Tesla coils won't normally kill you but can give nasty RF burns. You can get killed from a Tesla coil, if the spark can connects you to the low-voltage high-current driver. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.