Grounding is one of the most common issues when shielding electric fields. These must always be carried out by the electrician.
Large-area shields with shielding materials are not electrical equipment but “foreign conductive parts” according to IEV 826-03-03 or IEV 195-06-11 and thus a new method of DIN VDE 0100-100: 2009-06. By connecting to the equipotential bonding they are part of the electrical system, therefore, the recognized rules of technology must be observed.
According to the latest state of the art, a distinction is made between protection and functional potential equalization (FPA).
- The protective potential equalization (green / yellow cable) is used for protection purposes and is intended to ensure dangerous contact voltages by rapidly triggering protective devices (such as circuit breakers).
- Functional equipotential bonding (transparent cable) is used in large-area shielding to “minimize the emission of low-frequency electrical alternating fields”, ie the avoidance of Field displacements.
The connection of a functional equipotential bonding conductor to a power distribution board is as follows:
- Grounding is only permitted in buildings with TN-S, TT and IT systems. Under no circumstances may earthing be carried out in network forms with a combined PEN conductor!
- A fault current circuit breaker (FI / RCD) of no greater than 30 mA must be installed!
- For buildings with external lightning protection system, the provisions of DIN EN 62305-3 (VDE 185-305-3: 2006-10) must be taken into account.
Preferred order of how should be grounded
- The functional equipotential bonding cable must be connected directly to the FPA busbar in the circuit distributor (fuse box) using a 4 mm² cable.
- In exceptional cases, however, the functional equipotential bonding conductor can also be connected to “suitable protective conductors or protective compensation cables“. This exemption is important because otherwise no grounding would be possible in most homes without alterations to the fuse box.
- Grounding with a 2.5 mm² cable to a protective conductor in the electrical installation.
- Earthing with our GP grounding plug by screwing in the socket. Our earthing plug may only be plugged into a socket by a qualified electrician!
- Less suitable are metal pipe systems or separate earthing rods that are not integrated in the building potential equalization. However, pipe cutters or roders – depending on the country – can make sense in network forms with a combined PEN conductor, but in this case common regulations of the respective countries must be observed.