1 EXHIBIT 21 PREFORMED LINE PRODUCTS COMPANY SUBSIDIARIES Domestic Subsidiaries: Superior Modular Products Incorporated Asheville, North Carolina BBR Systems Ltd. See Scotland Below Foreign Subsidiaries: Australia Preformed Line Products (Australia) Ltd. Sydney, Australia Rack Technologies Pty. Ltd. Sydney, Australia Brazil PLP-Produtos Para Linhas Preformados, Ltd. Sao Paulo, Brazil Canada Preformed Line Products (Canada) Ltd. Cambridge, Ontario, Canada China Beijing PLP Conductor Line Products Co., Ltd. Beijing, China Mexico Preformados de Mexico S.A. de C.V. Queretaro, Mexico Scotland BBR Systems Ltd. Glenrothes Fife, Scotland Superior Modular Products Europe srl Superior Modular Products Asia Pte Ltd. South Africa Preformed Line Products (South Africa) Pty. Ltd. Pietermaritzburg, Natal Republic of South Africa 2 Spain APRESA - PLP Spain, S. A. Sevilla, Spain United Kingdom Preformed Line Products (Great Britain) Ltd. Andover, Hampshire, England