1 Listings - Electrical Engineers in Merthyr Tydfil Share this page on: Click on the Electrical Engineers listings below to get contact details for each business including phone number, website details, social media links, opening hours, photos and more. EFS SYSTEMS (UK) LTD Located In Merthyr Tydfil, Merthyr Tydfil Tel: 01685 388333 ELECTRICAL MAINTENANCE & CONTRACTING