An auxiliary wire feeder has a pushing device for advancing welding wire, a control device for controlling the pushing device, and an electric contact adapted for being in electrical connection with the welding wire. The electric contact is connected to the control device for supplying a control signal to the control device. A welding system comprises an auxiliary wire feeder of this kind and further a welding torch, a main wire feeder, a wire guide for guiding welding wire from a supply to the welding torch and a welding current contact for supplying welding current to the welding wire. For controlling an auxiliary wire feeder in a welding system having a welding torch, a main wire feeder, a wire guide for guiding welding wire from a supply to the welding torch, a welding current contact for supplying welding current to the welding wire, the control of the auxiliary welding wire feeder is responsive to an electrical signal transmitted via the welding wire.