The spring terminal blocks were designed mainly for jointing control circuit wires in 0,2 mm ² - 6,0 mm ² cross-section range in good quality, quick and reliable way. The terminal block can accommodate unprepared rigid wires, or twisted or flexible wires equipped with cord-end terminals or male lugs. The highly heat resistant, strong, self-extinguishing (according to UL94-V0) polyamide plastic house with good electrical parameters – witch contains the electrical elements - , is shaped in a way to permit the terminal block to be fixed onto mounting rails according standard EN 50022 („hat” or „C” rail).

They have same construction as the general purpose terminal blocks, however due to its blue color plastic house is suited for jointing the neutral conductor, being visually different from the phase conductor.