What voltage is safe then?
Voltages
- Thread starter ebee
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50v is considered a safe touch voltage.
That's AC or 120v DC!
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ebee,
you don't give up do you?
You asked the very same question here: -
//www.diynot.com/forums/viewtopic.php?t=40328&highlight=
There were a lot of very good replies but if you keep asking the same question AFTER is has already been answered, then members of this site will come to the conclusion that you cannot be bothered to remember or learn.
Then they'll think that their replies are a waste of their time.
MODS - please note repeated questions
you don't give up do you?
You asked the very same question here: -
//www.diynot.com/forums/viewtopic.php?t=40328&highlight=
There were a lot of very good replies but if you keep asking the same question AFTER is has already been answered, then members of this site will come to the conclusion that you cannot be bothered to remember or learn.
Then they'll think that their replies are a waste of their time.
MODS - please note repeated questions
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B
Big_Spark
Lectrician said:
Whilst I agree with Lec that 50V and below are considered relatively safe, in reality it will depend on your bodies resistance at the time of contact. Generally the body's natural dry resistance is high enough that the body is unable to induce a fatal current if the voltage applied is below about 50V, however this can change if the body is wet or you have a naturally low resistance.
Generally the natural body resistance is 1500 Ohms or above, usually significantly above this and I believe (I stand to be corrected) can be as high as 15k Ohms. Anyway, it is generally accepted that for a shock to be fatal then the body needs to pass a current of 20mA or more. At 1500 Ohms the body will have a current of 0.033A or 333mA pass through it, so this could be fatal if you have a low resistance, you need to have a resistance of higher than 2500 Ohms for the shock to be lower than 20mA at 50V.
Well I am correcting myself as I have found a reference in a book, the average body resistance is estimated to be 5200 Ohms and the upper and lower limits so far measured are 800 Ohms and 227k Ohms..so I think you should only mess about with live circuits of any voltage if your measured your dry resistance and it is significantly above 2500 Ohms
Incidently, I just measured mine and it came back at 17243 Ohms!
Excuse me it is NOT the same question!
I previously asked what voltage is dangerous.
I now asked what voltage is safe.
safe doesnot equal dangerous therefore it is a DIFFERENT question.
That would be like saying twice is the same as half or left = right.
Thanks all for the answers so far
I previously asked what voltage is dangerous.
I now asked what voltage is safe.
safe doesnot equal dangerous therefore it is a DIFFERENT question.
That would be like saying twice is the same as half or left = right.
Thanks all for the answers so far
bullshit
if no voltage could be considered safe then we wouldn't be selling batteries with bare metal contacts to the general public.
note that duration is important too! static shocks for example are both high voltage and high current but extremely short duration and so don't generally do people any damage (electronics can be another matter)
if no voltage could be considered safe then we wouldn't be selling batteries with bare metal contacts to the general public.
note that duration is important too! static shocks for example are both high voltage and high current but extremely short duration and so don't generally do people any damage (electronics can be another matter)
The question was not how long can a body withstand electric shock, it was what voltage is safe? What voltage is "safe" if you are being operated on in an operating theatre?
If used incorrectly batteries can cause fire. Is this safe?
If used incorrectly batteries can cause fire. Is this safe?
good debate I`m pleased with the answers.
It shows some thought here.
Another thought - why are voltages classifications higher at DC than AC?
Example Low voltage = 1000v AC & 1500v DC & Extra low = 50 V AC & 120v DC (in the regs)
Actually not equal but not exceeding
It shows some thought here.
Another thought - why are voltages classifications higher at DC than AC?
Example Low voltage = 1000v AC & 1500v DC & Extra low = 50 V AC & 120v DC (in the regs)
Actually not equal but not exceeding
B
Big_Spark
AC is more dangerous to the bodies systems for a given voltage as it has more effect on the electro-chemical impulses the body uses for communication.
Further DC has less effect on the heart muscle that AC voltages as the alternating voltage and current interferes with the heart's rythm.
Further DC has less effect on the heart muscle that AC voltages as the alternating voltage and current interferes with the heart's rythm.
It is also very odd to consider the telephone network...
50v DC supplied down the lines.
The exchange has huge battery banks to supply this voltage continuosly.
Does anyone want to hazard a guess as to the current these batteries deliver? Tip - ALOT more than you may think!
If ever you get the chance to have a look, you will be amazed. HUGE copper busbars in the battery rooms, naked to the touch - the chap that showed me grabbed hold of them without worry - but the current still scares me!
50v DC supplied down the lines.
The exchange has huge battery banks to supply this voltage continuosly.
Does anyone want to hazard a guess as to the current these batteries deliver? Tip - ALOT more than you may think!
If ever you get the chance to have a look, you will be amazed. HUGE copper busbars in the battery rooms, naked to the touch - the chap that showed me grabbed hold of them without worry - but the current still scares me!
0.033A = 33mA, not 333.....Big_Spark said:
You should take more water with it, old boy...
(PS - at what voltage did you measure it?
)
What's the peak-peak value of 1000V RMS?ebee said:
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