Manufacturing method for current detection coil e.g. for circuit breaker applications

A method of manufacturing a current detection coil (6) with a single layer winding includes preparing an annular coil winding body (1) made of plastics material, and winding the given coil winding body with the given single layer winding (2). A thermoplastics material is used to manufacture the coiling body (1), which is then equipped with the winding (2) and heated to a temperature sufficient to deform the coil winding body (1). The heated coiling body (1) is laid in to a moulding or forming tool (4) for converting the coiling body in to a shape deviating from the annular shape and the coiling body is left in the moulding or forming tool (3) until it hardens.