17Mar
Charging with Extension Cords is Risky
We take safety extremely seriously at OEM and provide free advice, an easy to read instruction manual and excellent after-sales service. Yet we find that our customers do not always read the safety instructions and their charging cable has stopped working. When used in a dangerous manner EV charging cables can cause electric shocks and electric fires, melting of the appliance, damage to homes and cars. Regardless of what some Facebook user said they’ve been doing for 4 years please always follow the safety guidelines and always have your premises checked by a qualified electrician before charging via household wiring.
As EVs become more popular in NZ there are more instances of dangerous EV charging. The most common that we see is use of an extension cord or charging lead to allow the car to charge a fair distance away from the power source. This can go wrong for all sorts of reasons. DO NOT USE THESE. Still not convinced? See Standards New Zealand SNZ PAS 6011:2023, page 37.
Why?
Voltage drop
The longer the cord, the more electricity voltage can drop. When the voltage drops, more electricity flows through the wires to make up the difference. The wires heat up and run hot which may cause melting. Do you want to run the risk of melting the cable to your wall?
Coiling
When the extra lengths of a long cord are coiled up, they can create an inductor which can get really hot, melt the outer insulation and cause fires.
Weather
Any old extension cord may not be rated for outdoor use. And please realise that any water-resistant rating is measured using exposure to a certain quantity of moisture over a certain period of time in a lab.
An IP65 rating given to electrical appliances can mean your EVSE will tolerate some forms of rain for 15 mins max.
The IP (Ingress Protection) scale has no truly “waterproof” rating. More information is available at consumer.org.nz https://bit.ly/Consumer_IP
Take away: An IP rating means resistance. It doesn’t mean your device is either waterproof or dustproof. Your device is still endangered by the water if exposed for a long period of time or by forceful rain/saturation.
There is always going to be someone who looks at the above list and thinks that by applying measures to the charging situation they can make using an extension cord safer, I mean they buy a 10-guage cord with a continuous use rating and it's not too long and is sheltered etc. But these attempts to make an unsafe situation safer is not reducing risk of fire or electric shock sufficiently.
Solution
Dedicated circuitry
Any outdoor charging should be in a weather-protected “in-use” outlet on a dedicated circuit. A person should also have a cover over the connection between the extension cord and the car charging cable.
Ask your electrician if they can run a wire properly to the car park and have an outlet and box mounted there.
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