Actually, this subject should have been dealt with in the motor car workshops much earlier. I myself have had problems with the mains voltage, when an oscilloscope, which was connected to the 220-V-mains through an earthed plug and, through a ground contact to a test-bench, which caused a short circuit. If the earth lead were not connected (not allowed), everything would have worked perfectly.

With the hybrid cars already found on the roads, the whole high-voltage technology thing becomes really up to date. One distinguishes between the available one-day courses (e.g., for the fire brigade) to learn to disable the system and multiple course seminars, e.g., for those who are entitled to remove the high-voltage batteries. Even then, one has not learned enough to repair them by, e.g., replacing the stacks.

We'll use the strong concern of the public as an opportunity, to deal with a few aspects of household technology, whereby the safety factor should not be underestimated. Because this subject is of course, of general interest, one should first of all read this article which is not very long.

As a rule, the electric power is fed into the building's fuse-box by cable, whereby, the wire-colours, black and brown are reserved for the three phases (L1 - L3), the blue wire is the zero-conductor (N) and the green/yellow wire is the earth. In the case of the workshop, the cables go straight through because, as a rule, high consumption equipment is used and stationed there.

For household use, the three phases are separated, whereby each one, together with H and PE, provides a supply source. The electric cooker/oven is not really an exception, although three-phase current comes in here, it is then separated, e.g., between the cooking plates and the oven. A very important point is the staggering of the fuses which can begin at 64 Amp, to which private housholders do not have access.

Then, all the circuits are secured again through a triple-fuse with a lower current value, thus also protecting the high voltage circuit, the reconnection of which, can only be done by authorized experts (probably for a fee). Individual circuits are then mostly limited to 16 Amperes. Different than in the motor car, they don't have to be replaced after tripping out. 08/11