A housing includes a main portion and at least one insulating portion. The main portion includes two portions, an inner surface and an outer surface opposite to the inner surface. The inner surface defines at least one groove. The outer surface defines at least one gap that is coupled to the at least one groove. The at least one insulating portion is corresponding to the at least one groove and each insulating portion is filled in one groove. The two portions of the main portion are positioned at two sides of the at least one gap and the two portions are insulated by the at least one gap and the at least one insulating portion.