Before it lets any power flow, a home EV charger runs a short self-test at the start of every session. It confirms the connector is seated, that the protective earth is connected, that no current is leaking where it should not, and that its own main switch, the contactor, is not stuck shut. If a check fails, the charger stays off and shows a fault instead of charging. The whole routine takes the few seconds you wait after plugging in.
Key Takeaways
- Every session starts with checks: seating, earth, leakage device, contactor, temperature.
- The welded-switch check proves the charger can still cut power before it supplies any.
- The charger’s self-test complements, and never replaces, protection in your wiring.
- A repeated refusal is information. Find the cause; do not bypass it.
The Start-Up Checklist
| Check | Why it matters | If it fails |
|---|---|---|
| Connector seated and latched | Power must never flow into a half-connected plug. | No start. Reseat the connector until it latches. |
| Protective earth present | The earth connection is the path that lets protection work if a fault develops. | No start. The wiring needs a licensed electrician. |
| Leakage self-test | The charger proves its ground-fault device can still detect leakage before it relies on it. | No start, fault indication. This is the charger’s own device, separate from the breaker. |
| Contactor not welded shut | The main switch must be able to open. A switch stuck closed would defeat every other protection. | No start. Do not retry repeatedly; contact the manufacturer. |
| Temperatures in range | Electronics and connections must start the session within their safe limits. | Delayed or refused start, especially after a hot day or a fault. |
The welded-switch check surprises people, but it is the logical one. Every other protection depends on the contactor being able to cut power, so the charger verifies its switch before it trusts it. What each fault light or code means for that check is model-specific; the manual is the authority.
How This Relates to Your Breaker
The self-test covers the charger’s own protection. It does not replace the layers in your wiring. The explainer on whether an EV charger needs GFCI protection sets out how the charger’s built-in ground-fault device and a GFCI breaker divide the work, and the guide to RCD protection for EV chargers covers the European equivalent, including DC fault detection.
The Checks Do Not Stop at Start-Up
Passing the self-test opens the session; it does not end the supervision. While charging, the charger keeps watching the same things: leakage, temperature, the connection signal, and whether the car is still asking for power. Any serious problem opens the contactor and ends the session. That continuous monitoring is part of the design described in how home EV chargers work.
Chargers such as the EVDANCE EV-ACT3204PE 22 kW wallbox and portables such as the EVDANCE EV-ACS4005T 40A NACS portable charger all run a version of this routine. You never configure it; you only see its result, a start or a refusal.
If the Charger Refuses to Start
- Unplug, check the connector and socket for damage, dirt or moisture, and plug in again firmly.
- Try the car’s other charging settings, such as removing a schedule, so the refusal is not a settings clash.
- If the same fault returns, stop there. Do not open the unit, and do not keep cycling power.
- Earth, leakage and welded-switch faults belong to the manufacturer or a licensed electrician.
Frequently Asked Questions
Does the charger run the self-test every time?
Yes, a start-up routine runs at each session start on typical home chargers, and monitoring continues for the whole session. Exact behaviour varies by model.
Can a self-test fail on a healthy charger?
It can refuse because of conditions around it: a poorly seated connector, moisture in a socket, or a missing earth on an old circuit. The refusal is still doing its job; have the cause found rather than bypassed.
How long should the checks take?
A few seconds is normal. A long delay, repeated clicking, or a fault that appears every session deserves attention, starting with the manual’s fault guide.
Related Reading
- Does an EV Charger Need GFCI Protection?
- RCD Protection for EV Chargers: Type A, Type B and 6 mA DC Detection Explained
- How Do Home EV Chargers Work?
- Are Home EV Chargers Safe?
