The 100, 300 and 400 series circuit distributors are equipped with E-T-A 1140 series thermal circuit breakers. Standard are the 8A types, on request 4A, 6A, 8A, 10A, 12A or 16A automatic circuit breakers can be used without extra charge. The connection is made by means of 6.3 mm flat receptacles on the back of the devices. A labeling sheet “STKZ” with self-adhesive labeling plates is supplied.