Mode of operation of a protective separation
The protective effect consists of a galvanic separation between the consumer circuit and the power supply network. Usually, the outer conductors of a network have a voltage to ground. This is not the case with a circuit to which the protective disconnected device is connected.
The protective separation offers a higher protective effect than, for example, protection class III, which is why it is prescribed for areas with increased danger. It is preferably used in wet rooms, in and on steel boilers, when operating power tools on construction sites, or when working in confined spaces. It is also occasionally used in the operation of small appliances, such as razors.
Furthermore, protective cables are suitable for use in systems with a maximum operating voltage of 500V and the cable length must not exceed 500m. In case of prescribed use, only one electrical consumer may be connected. When connecting several devices to an isolating transformer, an earth-free, local equipotential bonding must be established between the individual devices.
Protective separation can only be applied at localized points, since it is only effective as long as there is no ground fault on the secondary side and thus the expansion of the line connected there must be limited.