The return connector must be properly dimensioned to provide good contact for the welding current load to be used. The positioning of the return clamp determines how large a part of the vessel or of the work piece is to be utilized as part of the welding current circuit. The return clamp should always be placed as close as possible to the welding area, or on the work piece itself if this is not an integral part of the hull. The thickness of material between welding point and return clamp must be sufficient to carry the current load that is to be used. Think carefully before fixing the return clamp so that sensitive machine parts such as ball bearings etc. are not used as a bridge for welding current. There are four types of return clamps available: the 200A, 400A, 600A and 800A.