Symmetrical distribution of the control devices across all phases is advantageous. Follow the installation instructions provided by the control device manufacturer. The function of the switch is independent of its position. Therefore, the protective switch can be used in accordance with the installation regulations for fault protection and additional protection. The 4-pole switch can also be used as a 2-pole or 3-pole switch. See connection examples. The test button "T" must be pressed once a year. The system operator must be informed of this requirement and its responsibility in a verifiable manner. In special conditions (construction sites, laboratories), the test button may need to be pressed more frequently. The statements of the respective installation regulations apply here. Pressing the test button "T" only tests the function of the residual current (RCD) protection switch. This test does not replace the earth resistance measurement (RE) or the proper protective conductor state check, which must be carried out separately. Type B: Short-time delayed and surge-resistant 3 kA, all-current sensitive, Type B (ÖVE E 8601). Type B: High reliability against false tripping. Mandatorily required for circuits with potential risk of personal injury or property damage in the event of false tripping (ÖVE/ÖNORM E 8001-1 § 12.1.6). Type S/B: Selective and surge-resistant 5 kA, all-current sensitive, Type S/B. Type S/B: Selective residual current protection switch. Protects against all types of residual current forms.