Symmetrical distribution of the control devices across all phases is advantageous. Follow the installation instructions provided by the control device manufacturer. The switch operates independently of its position. Therefore, the protective switch can be used in accordance with 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 plant 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) protective switch. This test does not replace the earth resistance measurement (RE) or the proper protective conductor condition check, which must be carried out separately. Type B: Short-time delayed and surge-resistant up to 3 kA, all-current sensitive, Type B (ÖVE E 8601). Type B: High reliability against false tripping. Mandatorily required for circuits with potential personal or property damage in the event of false tripping (ÖVE/ÖNORM E 8001-1 § 12.1.6). Type S/B: Selective and surge-resistant up to 5 kA, all-current sensitive, Type S/B. Type S/B: Selective residual current protective switch. Protects against all types of fault current forms.