Form factors of RCDs
Residual current devices (RCD) are commonly incorporated in or associated with the following components:
- Industrial-type molded-case circuit breakers (MCCB) and air circuit breakers (ACB) conforming to IEC 60947-2 and annex B or M
- Industrial type miniature circuit breakers (MCB) conforming to IEC 60947-2 and its annex B or M
- Household and similar uses miniature circuit breakers (MCB) complying with IEC 60898, IEC 61008, IEC 61009, IEC 62423
- Residual load switch conforming to particular national standards
- Relays with separate toroidal (ring-type) current transformers, conforming to IEC 60947-2 annex M
RCDs are mandatorily used at the origin of TT-earthed installations, where their ability to coordinate with other RCDs allows selective tripping, thereby ensuring the level of service continuity required.
Industrial type circuit breakers with integrated or adaptable RCD module
(see Fig. F48)
Industrial circuit breakers with an integrated RCD are covered in IEC 60947-2 and its annex B
Adaptable residual current circuit breakers, including DIN-rail mounted units (e.g. Compact or Acti 9), are available, to which may be associated an auxiliary RCD module (e.g. Vigi).
The ensemble provides a comprehensive range of protective functions (isolation, protection against short-circuit, overload, and earth-fault).
Household and similar miniature circuit breakers with RCD
(see Fig. F49)
Household or domestic circuit-breakers with an integrated RCD are covered in IEC 60898, IEC 61008 and IEC 61009
RCDs with separate toroidal current transformer
(see Fig. F50)
RCDs with separate toroidal current transformers are standardized in IEC 60947-2 annex M
RCDs with separate toroidal CTs can be used in association with circuit breakers