Not really.
Low voltage is considered not dangerous at all, especially something
like 10V.
Touching car battery terminals, for example, would not give you a shock,
no ?
Adding 1 million batteries in parallel still wont give you any more shock.
The high voltage directive in the EU was for 80V DC, iirc.
Low voltage high current power sources like welders are considered
relatively safe.
I believe 30-50V for welders ?
And a 3 kW welder would thus put out 30 V at 100 amps.
My AC welder puts out 200 amps, and they are not considered especially
dangerous.
Edit:
Went to look at it.
7.1 kV max, 56 V max, 26 V DC at 100% duty cycle (==5.2 kW).
Single phase, in europe.
The problems are 2 different issues.
At high(er) voltage, you are much more likely to get a shock, as it will
more readily travel through insulation.
Wet materials and environment may make this easier.
With DC if you get trapped you find it hard to let go ? afaik, ..
as with AC you can let go, but the voltages start at 220V (apart from
the US, basically). And because line-power power is always high, you
could get several amps, that could definitely kill You, unless GFIs are
used.
Today, due to the protective GFIs, usually at 30 milliamps (bigger ones
exist and are sometimes permitted/used. Special cases), line power is
not actually dangerous.
The GFIs trip, and the line in unpowered - but it hurts.
I have had 3-5 major shocks from 240V AC lines - not big deal, just very
unpleasant.
A 240V DC bus, however, AFAIK, will deliver a lot of power, potentially
in ms.
Thus, if the power source has the ability to deliver that high current,
it would go through you at wherever you touched it.
For example, if a *DC* power source, like from high voltage batteries
(or a motor controller) went through your fingers, at say 100 amps x 240
V, = 24 kW, this could burn/vaporise your fingers within some short
amount of time.
High power motion batteries can certainly deliver 24 kW of power, and
more, for a short amount of time.
Otoh, even Ac if at 240V AND also at high current, = high power, like 24
kW, would probably be bad news.
E.g. most households in Spain are about 10 kW.
After a certain power level, 15 kW (maybe 20 kW) special regs come into
effect.
On 16/06/2015 12:57, Stefán Brandur Jónsson stefan@martolvan.is
[electricboats] wrote:
> AC and DC are both dangerous if you have the power to drive some KW it
> can fry you with that energy regardless of voltage or AC/DC higher
> voltage needs bit thicker insulation but less copper Kilowatt is
> kilowatt of energy, no matter if it is 10Volts x 100Amperes or 100
> Volt x 10 Amperes, there is mainly the difference that more current
> all connections are under far more stress from current and wires are
> lot heavier copper is far heavier than insulation.
--
-hanermo (cnc designs)
Posted by: Hannu Venermo <gcode.fi@gmail.com>
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a New Topic | • | Messages in this topic (11) |
No comments:
Post a Comment