The ECS (Electrotechnical Certification Scheme) card shows your identity, your electrotechnical occupation and your qualifications. ECS describes itself as the only identity and competence card scheme for UK electrotechnical workers. The JIB runs it in England, Wales and Northern Ireland, and the SJIB runs it in Scotland. Before 2002 people called it the JIB card, and many still do. These are scheme facts, as ECS states them in October 2026.
No law requires an ECS card. A principal contractor or client may ask for one, and ECS says it is often a site requirement. The law asks for competence instead: CDM 2015 regulation 15(7). Holding a card does not get you onto a site by itself, because the principal contractor controls access.
ECS is a partner of CSCS. The CSCS hologram on an ECS card shows that partnership. CSCS issues cards for core construction occupations only and sends electrotechnical workers to their own scheme, so most electricians hold an ECS card rather than a CSCS card.