In equipment for powder-coating, workpieces such as escalator steps are subjected to a current treatment in an anodizing unit. A conveying means advancing carriers for the workpieces is lowered over a tank so that the workpieces in transit are immersed in and continue transit within a bath and after a specific dwell time are lifted back out of the bath at the end of the tank. Arranged in the tank region is a current feed, such as a bus bar, which extends parallel to the travel path of the conveying means. Each carrier is provided with a current take-off which connects the carrier with the current feed. The current connection is produced on lowering the carrier into the bath and interrupted on raising the carrier from the bath.