Charging outdoors safely

Rain is not the risk. EV charging equipment is designed for wet conditions, and the charger will not energize the cable until it has verified the connection to the car. The genuine risks in outdoor charging are a bad receptacle, an unmanaged connection, a cable somebody can trip on, and heat at a joint — and every one of them has a free fix.

• The connection sequence. The cable is not live until the car and the charger have confirmed a proper connection. Picking up a connector is not picking up a live conductor.
• Ground monitoring. The EVSE watches the ground connection continuously and stops if it faults.
• Water on the connector. Both the vehicle inlet and the coupler are engineered for it. A wet connector is a designed-for condition.
• Overcurrent. The charger limits current to its configured setting and the circuit breaker sits behind that.

That list is why the hand-wringing tone of most outdoor-charging articles is misplaced. The equipment does a great deal of the work.

The receptacle

An outdoor receptacle should sit in a while-in-use enclosure — the deep bubble cover that closes over a plug — rather than a flat flip-lid that a plug props permanently open. A propped-open lid is an open socket facing the weather. Asking a building for a while-in-use cover is a cheap, reasonable request.

Anything upstream of the charger

The EVSE protects what is downstream of it. A household extension cord between the wall and the charger is upstream, and nothing is watching it. This is the single most important geometric fact in outdoor charging and it has its own page.

Heat at a connection

Contact resistance turns current into heat, heat degrades the contact, and the cycle compounds over weeks. Nothing in the system is monitoring the temperature of your plug in its socket. That is what the hand check is for.

People walking past

A cable across a path is a trip hazard and no equipment feature addresses it. It is the one thing on this site we offer no workaround for — see street parking.

1. 1A drip loop. Let the cable hang below the outlet before rising to the plug, so water runs to the low point and drips off instead of running into the socket. Free, and it prevents the most common outdoor receptacle failure.
2. 2Connector off the ground. A hook, a cleat, a holster or a bag over the end. Keeps the coupler out of puddles and grit between sessions.
3. 3Nothing coiled while it is working. A coil cannot shed heat and its middle is the hottest point.
4. 4A hand on the plug after the first long session, and again after the first hot day and the first cold snap. Warm is fine; hot means stop.
5. 5A route nobody walks on. Along a wall, behind a wheel stop, under the car. Never across a doorway or a path.

Outdoor receptacles are generally required to have ground-fault protection, which is a good thing and occasionally an irritating one: some combinations of EVSE and GFCI produce nuisance trips, because the charger has its own ground-fault detection and the two interact. A charger that repeatedly trips a GFCI is annoying rather than dangerous, and it is worth knowing the phenomenon exists so you do not conclude something is broken. If it happens persistently, that is a genuine reason to mention it to the building.

• Do not force a frozen connector. Warm it with a hand or wait. Levering an iced latch breaks the latch.
• Clear snow from the inlet before connecting, so it does not melt in and refreeze.
• Keep the cable off ground where it can freeze into ice. Freeing it is what causes the damage.
• Expect slower charging and plan around it rather than assuming a fault. How long charging takes has the numbers.

A warm or discoloured faceplate; a plug that fits loosely; any smell of hot plastic; a breaker that trips more than once; a receptacle that visibly moves in the wall. None of those is a reason to buy a different charger — they are reasons to report the outlet and use a different one until it is looked at.