In TN systems, the star point of the feeding transformers is connected to earth through a low impedance and the exposed conductive parts of the electrical installation are connected to the protective earth (PE) of the system. In TT systems, the star point is also connected to earth through a low impedance but the exposed conductive parts of the electrical installation are earthed independently from the system earthing.
In TT systems, one point is connected directly to earth (functional earthing). The exposed-conductive parts of the electrical installation are connected to earth electrodes which are electrically isolated from the earth electrode for earthing the system.
Permissible protective devices:
Продукция
Four-channel DC, AC and pulse current sensitive residual current monitor for earthed AC, AC/DC and DC systems
Система поиска повреждений изоляции для систем пофидерного контроля изоляции в сетях питания
Four-channel DC, AC and pulse current sensitive residual current monitor for earthed AC, AC/DC and DC systems
Система поиска повреждений изоляции для систем пофидерного контроля изоляции в сетях питания
