Key facts
- AC and DC residual currents are different hazards; some charging equipment integrates detection functions.
- Requirements depend on local electrical regulations and the installer's assessment.
- Homeowners should request the circuit design, testing results, certification and manufacturer's installation instructions.
Quick answer: The important question is not simply “Does my EV charger have an RCD?” but which residual-current and DC leakage protection the specific installation provides, where each protection is located, and whether the configuration complies with local wiring standards. Only a qualified electrician should design, test or modify the circuit.
Why AC and DC faults are discussed separately
RCD means residual-current device. In EV charging systems, protection against AC residual currents and detection of certain smooth DC residual currents may be provided by different equipment. The charger manufacturer’s documentation and relevant national installation standard determine the approved arrangement; a product’s advertising label is not a full installation certificate.
The seven questions worth taking to a site survey
- What local electrical standard applies to this property and this supply type?
- Is a dedicated circuit and protection arrangement required for this charger?
- Where is residual-current protection installed and what type is specified?
- Does the charging unit itself contain DC residual-current detection, and how is that documented?
- Has the installer assessed earthing, supply capacity and any open-PEN considerations where relevant?
- What commissioning and periodic testing records will be provided?
- What should the owner do after a protective trip, and which issues require the installer to attend?
Example: an integrated detector is not proof of complete safety
Imagine Charger A lists internal DC leakage detection, while Charger B requires a separately specified protective device. The equipment’s internal function could affect the type of upstream protection selected, but it does not establish that either installation is compliant without considering the upstream circuit, local standard and manufacturer’s requirements. This is an illustrative comparison, not a wiring instruction.
What you should receive in writing
Ask for the charger model, approved installation manual, commissioning test results, protective device specifications, supply assessment and emergency isolation instructions. Check who can service the unit under its warranty, and whether the installation records need to be filed with a local authority or utility.
Warning signs that require professional help
Repeated protective-device trips, scorching, overheating, damaged connectors, water ingress, unusual smells or unexplained charging interruptions should never be “fixed” by bypassing safety devices or altering wiring. Stop using affected equipment and seek qualified professional help. Our charger load balancing guide covers a separate supply-capacity issue; outdoor IP ratings address enclosure ingress, not complete electrical safety.
Global applicability
The UK has its own installation rules and grant guidance, and other countries use different national codes, inspection schemes and plug systems. This guide deliberately avoids prescribing a universal Type A/Type B wiring layout or a trip threshold. Use Electrical Safety First and the relevant national regulator as general starting points, then obtain local design advice.
Frequently asked questions
Can I install or replace the protective device myself?
No. Electrical protection and certification are professional work subject to local law.
Does a waterproof charger eliminate the need for RCD protection?
No. Enclosure weather ratings and fault protection address different risks.
General safety information, not electrical installation instructions. Check applicable law and manufacturer documentation.