Electrical systems and equipment of up to 1000 V 2.1. Impedance Zs of the ‘Phase-protective conductor’ contour and neutral earthing of electric outlets; 2.2. Protective circuit breakers, starting current, starting time, ground conductor resistance and contact tensions; Testing of residual current protection SERVICESElectrical construction Evaluation Electrical systems and equipment of up to 1000 V and above Electrical systems and equipment of up to 1000 V Physical factors of the work environment