LV 124 is the best known of the joint requirements drawn up by several German vehicle manufacturers, and it covers the electrical rather than the electromagnetic behaviour of components in vehicles up to three and a half tonnes: the electrical conditions of the supply, the behaviour of a component over the operating voltage range, its response to the transients produced when loads are switched, its consumption and its behaviour under abnormal conditions such as overvoltage, undervoltage and reverse polarity. The document is valued because it is common to several manufacturers, so a component qualified against it can be offered to more than one programme, and because the market has moved in the same direction with the introduction of the forty eight volt system for which the standard now provides explicitly. Its companion requirement in the same family covers the electromagnetic compatibility of the same components, and the two are normally applied together.