Handwriting

[rof120]

Many thanks for all your interesting replies.

Nick: The Vercors Plateau action of July 1944 was the biggest of this period (…)

- Yes, you’re right. When I mentioned Résistance people keeping quiet I was meaning the area (here in the Drôme département, Vaucluse too, and more) more or less directly on the banks of the powerful river Rhône. The general instruction to the Résistance all over France was to wait for the Allied landings before starting any action, but the Vercors battle obviously was an exception. There were others like sabotage of railroads, telephone cables etc. but “normally” no fighting (yet).

Stig: In short, it is not actually the Voltage that kills us, it's the Ampère.

- Hmmm, I wouldn’t go so far. Example: a car battery gives only 12 volts but is relatively powerful (it’s able to start even a heavy car engine, normally even in difficult conditions like freezing temperatures which make the oil almost solid). I don’t think anybody in the world ever was killed by the current (nor by the voltage) of such a car battery. If the voltage is too low no current is going to flow through a human body. In legal regulations about safety, voltages under 50 V (??? – I’m not sure – perhaps 30 V?) are considered innocuous On the other hand if your hand or any other part of your body has contact with some metallic part of some electrical equipment having a voltage of, say, 500 volts or more against the ground, you’re pretty sure to be killed or at least badly wounded. Over 1,000 V it’s virtually certain but I don’t know the real limits (and they vary according to circumstances like wet or dry ground and more).

Stig: Having said that it is of course a combination of the two which makes the trick.

-Yes, I guess so. But never forget that each year thousands of persons are killed or badly wounded, often in their very homes, because they touched some metal part having “only” 220 volts. The current (in milliampères – milli means one thousandth) can be very weak: in most cases people die because the current, even a weak one (perhaps 0.1 A with 220 V), has a very adverse effect on their HEART, which is the main victim of such accidents (electrocution) and results in most death instances. The brain can be badly damaged or destroyed too if the voltage is high enough. The fact that it is alternating current or AC makes things much worse for human hearts.

380 V voltage is extremely dangerous too (of course much more dangerous than 220 V). It is used by professionals only (the general public doesn’t even know of its existence) but the 220 V we all use (at least in continental Europe) is so to speak, in most cases, “extracted” from a 380 V supply, which is simpler and cheaper to use. The details and explanations about this are purely technical and off topic here. The higher the voltage in cables including in power cables (up to 380,000 V and more) the cheaper the transportation of power because if the voltage is higher the transportation cables are thinner, hence cheaper (copper cables etc.).

Stig: In Germany (and Sweden) we don't mention any names (Volta or Ampère).

- Hmmm… är du helt säker på det ? (Are you quite sure?) Jag bodde i Sverige I över 3 år och märkte aldrig detta. (I lived in Sweden for more than 3 years and I never noticed.) Same thing for Germany (18 years there). Oh yes – OK, we don’t mention the full names but we do mention the physical units volt and ampère and their symbols V and A (just like meter/m, gramme/g or second/s). In the USA they mention “the amps”.

Rasmussen: In Germany up to the year 2000, all single or multi-phase installations up to 1000 V were referred to as high-voltage systems in the VDE regulations that were not low-voltage systems (colloquially low-voltage systems). In more recent VDE regulations, however, systems up to 1000 V are now referred to as low-voltage systems. Since then, only standards for systems with a nominal voltage of over 1000 V have used the term high-voltage systems. In contrast, the DIN 276 standard for determining construction costs names all electrical systems that are not used exclusively for signal transmission as high-voltage systems.

- I had no idea even though I was living in München until December 2002. German radio and TV didn’t mention this (at least not at “normal awake” times). I presume only professional people in electrical engineering were aware of this (were informed), and still are. ETZ (Elektrotechnische Zeitschrift of VDE, IIRC) certainly published articles on this.

Besides, in my 1st reply I simply forgot to mention that earlier the opposite of “Starkstrom” (strong current) was “Schwachstrom” (weak current), used mainly for radio, TV, telephone, electronics. Indeed, the current intensity in amperes is mostly very low there.