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Old 16th November 2012, 11:12 PM   #241
M Gregg is offline M Gregg  United Kingdom
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Quote:
Originally Posted by JRGuitarGuy View Post
even if it was possible to have an adequate amount of current it has no push(Voltage) to be deadly
Interesting..Hummm...25V not enough voltage to be dangerous...

Well if you think about some heater wiring...what voltage is the low voltage at?

Some are lifted...It would be interesting to grab hold of a 12V supply and get a shock of 100V...Then the capacitor explode as the low voltage cap now finds it has 100V across it to Gnd.. as the screwdriver drops out of your hand..

So the point is things are sometimes not what they seem...never take anything for granted..Its always the thing you never expected to happen that catches you out...Like the low voltage relay that turns on the B+ when you accidently short it to Gnd..

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M. Gregg
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Old 17th November 2012, 05:29 AM   #242
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Quote:
Originally Posted by M Gregg View Post
Some are lifted...It would be interesting to grab hold of a 12V supply and get a shock of 100V...Then the capacitor explode as the low voltage cap now finds it has 100V across it to Gnd.. as the screwdriver drops out of your hand..

So the point is things are sometimes not what they seem...never take anything for granted..Its always the thing you never expected to happen that catches you out...Like the low voltage relay that turns on the B+ when you accidently short it to Gnd..

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M. Gregg
You can add really long low voltage DC transmission lines like CCTV installations generating a static charge during or just after a thunderstorm to that list...
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Old 17th November 2012, 06:59 PM   #243
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I was under the impression we were talking on this thread about A 24 VOLT BATTERY and not a circuit that get controlled by a relay with 24 volt coil! On the contacts can be anything but battery operated stuff shock you except if you make an inverter then it is NOT 24 volts anymore, but what got generated please get serious man!
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Old 17th November 2012, 07:08 PM   #244
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Exclamation Heater @ 12 volts?

Quote:
Originally Posted by M Gregg View Post
Interesting..Hummm...25V not enough voltage to be dangerous...

Well if you think about some heater wiring...what voltage is the low voltage at?

Some are lifted...It would be interesting to grab hold of a 12V supply and get a shock of 100V...Then the capacitor explode as the low voltage cap now finds it has 100V across it to Gnd.. as the screwdriver drops out of your hand..

So the point is things are sometimes not what they seem...never take anything for granted..Its always the thing you never expected to happen that catches you out...Like the low voltage relay that turns on the B+ when you accidently short it to Gnd..

Regards
M. Gregg
With 12 volt it will BURN but shock on a battery ....................??? Then I must have the thickest insulated skin on Earth I worked on a "HI RACKER" in a freezer (-40 c) It had a cab heater that worked on 72 volts and I touched the cables with my bare hands and I got a SLIGHT tingle but if you are talking about the electric mains then if the "LOW" side go open and you touch that then yes it can kill you as the resistance is then too low to drop the voltage to a safe value
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Old 17th November 2012, 10:02 PM   #245
M Gregg is offline M Gregg  United Kingdom
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Originally Posted by krokkenoster View Post
I was under the impression we were talking on this thread about A 24 VOLT BATTERY get serious man!
Thread title..

General and Ultra-High Voltage...

Low voltage heaters on SRPP..are usually lifted..

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M. Gregg
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Old 16th December 2012, 05:16 AM   #246
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Some sayings that I did not see while reading this thread -

It ain't the KiloVolts that kills ya, it's the MilliAmps -from a friend that used to work for the electric company.

Two places you never want the electricity to go - through your heart, or through your head.

It will kill you before it scars you. The shock through the heart that initiates ventricular fibrillation kills most often. 48 Volts is more than enough, when backed up with adequate current.

There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves.
- Will Rogers -


Peeing on a power supply is not a learning experience, it is a dying experience.

Reasonable precautions never eliminate risk, but they just might save you when you do something stupid. Eventually, we all do something stupid.
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Old 16th December 2012, 09:46 AM   #247
M Gregg is offline M Gregg  United Kingdom
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Quote:
Originally Posted by AllIsParadox View Post

There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves.
- Will Rogers -


Peeing on a power supply is not a learning experience, it is a dying experience.

Reasonable precautions never eliminate risk, but they just might save you when you do something stupid. Eventually, we all do something stupid.
A bit off topic, however..

Reminds me of the group of lads after having a drink in the local pub...then one stood on the side of the bridge (showing off in front of the girls) and took a pee and zap dead..straight onto the overhead power lines for the trains which were now under him through the tunnel. Its always the things you don't expect to happen that catch you out..

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M. Gregg
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Old 28th December 2012, 05:47 AM   #248
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When working on power amplifiers be aware that when driven at full output there are some substantial voltage spikes on an output tube plate. If you get a finger too close to a plate connection it can jump out at you.

If you every get careless and pick up a hot chassis and get your hand locked across high voltage, try swinging you body and fling the chassis out of your hands. First hand advise from my father who worked on old radios.
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Old 28th December 2012, 07:06 AM   #249
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Safety regulations are not just about high voltages, but also hazardous energy levels.
Take for example an industrial 12V battery (cellular base station back up) and what happens if you drop a tool acrooss the terminals. The molten metal flying around is definitely dangerous.
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Old 29th December 2012, 02:47 PM   #250
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Default Has anyone mentioned heatshrink?

When I'm building tube stuff with HT supplies, all connections where ≥500V will be present get a second layer of heatshrink tubing; all connections where there'll be ≥1000V, get 3 layers - never hurts!

Also, it's very rare to find a resistor rated at >500V; most are rated 250-350V, w/carbon comps typically being rated for higher V (at the same wattage) than metal or carbon films.
If you're dealing with 1kV+, it's best to string 4 resistors (of ľ the intended value) in series instead.
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