EV Charger Pitfalls and Observations from an Electrician

evhorizons

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Having been made redundant from Virgin last year, I trained to become an electrician. I also became certified to install EV chargers. My business is now NICEIC registered and certified to install several of the EV chargers on the market, including Zappi, Podpoint, Andersen, Rolec and Wallbox.

From an electrician’s point of view there are quite a few things to think about when installing an EV charger. There is a lot more involved than simply connecting a 7kW charger to your existing supply. Firstly, a 7kW charger will potentially be drawing 32 Amps on a continuous basis when charging. We have to notify the Distribution Network Operator prior to installing an EV charger if the maximum demand of a property exceeds 60 Amps. This will likely be the case in most houses when you take into account the current demand of electric ovens, showers, induction hobs etc.

The earthing arrangement of a property must also be determined as this can potentially introduce the risk of electric shock. Until recently it was necessary to install an earth rod on a PME earthing supply when fitting an EV charger. This was due to the risk of electric shock should there be a loss of the Protective Earth and Neutral (PEN) conductor. This fault happens on the electricity distribution system supplying the property but can lead to a potentially dangerous voltage arising on any exposed conductive surface – such as an electric vehicle when it is plugged into the EV charge point. EV charger manufacturers are now starting to incorporate an open PEN fault detection device which will disconnect the charger if a fault of this nature occurs. This is a huge improvement as these chargers no longer require the installation of an earth rod on a TNCS system.

An EV charger has to be on a separate circuit and cannot just be spurred off another power circuit. This introduces potential problems with regard to where the circuit will originate. There are a couple of options here. Firstly, if there is a spare way in the existing consumer unit (fuse board), the charger circuit can be installed from there. This is subject to the electrician being able to source a circuit breaker compatible with the consumer unit. Often it is much easier to install a new small consumer unit instead.

As a new circuit is being installed to accommodate an EV charger, Building Control must be notified. This involves the electrician having to test & inspect the electrical installation and issue an electrical installation certificate. Only Part P registered electricians are able to do this. Also, the electrician must have completed a specialist EV charger installation course.

As the electrical designer, the electrician must calculate the type and size of cable required for the EV charger. This very much depends on the length of cable required and the route it will take. An EV charger installed close to a consumer unit on the side of a house is a relatively easy installation and will likely only require either 4mm or 6mm cable. This will usually be steel wired armoured cable clipped to the side of the house but some electricians may also utilise Tuff Sheath cable. If you are really lucky, the electrician may be able to find a route from the inside of the house straight into the back of the charger using twin and earth cable. At the other end of the spectrum, an EV charger may be required on an outbuilding or detached garage which may be a long way from the house. This will likely require a significant amount of work. A trench will probably be required to bury the cable in. Due to the voltage drop, a much larger cable will probably be required (10mm/16mm). This cable is quite expensive and must be steel wired armoured. The trench also has to be deep enough to avoid mechanical damage. A minimum a depth of 50cm is recommended.

Another consideration is the requirement for RCD protection. Some EV chargers have integrated type ‘A’ RCDs which can detect DC leakage. If not integrated, an ‘A’ type RCD will need to be installed in the consumer unit. The electrician may not be able to source one that is compatible. Again, a new consumer unit will probably be required. Also, if the charger has an integrated RCD, the electrician will need to determine whether the cable itself requires RCD protection. This introduces the requirement for RCD selectivity if there are 2 RCDs on the same circuit.

One of the requirements to become eligible for the government OZEV grant is that the charger must be one of the prescribed “smart” chargers. These chargers require an internet connection and some of them can also incorporate load monitoring. This can be achieved wirelessly with some of the chargers, but will sometimes require a wired data connection. Some power cables on the market today incorporate a data cable but they are more expensive. Should a charger be on a detached garage, the wireless signal may be weak and an additional data cable will likely be required.

As you can see above, there are quite a few additional considerations to think about when installing an EV charger. Some of these considerations may well introduce a significant increase in the installation cost.

Any questions, please ask.
 
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evhorizons

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Yes, I’ve seen that one, thanks Danny. Those guys at Efixx & GSH electrical are very informative. There are quite a few good videos by Jordan at Artisan Electrics too. 👍
 

evhorizons

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A Zappi I installed today. I love the way it monitors the electricity your house is consuming using the Harvi and can then vary the output to your car.

F27AC55D-F4D0-449C-94BC-E1302E6509FE_1_105_c.jpeg
 
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danny

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Very neat. What’s going to happen when that vine is in full leaf in the summer and the tendrils start to wrap around it?

I got my PodPoint with the car and it’s inside the garage. Not impressed nor unimpressed with it. It will regulate voltage if total house consumption ever reaches limits but I tend to set charge for early morning hours anyway as there’s virtually nothing else on in the house at that time anyway.

I keep hearing that PodPoint are going to introduce a timer function to actually make their charger a bit “smarter” but I’m not going to hold my breath.
 

evhorizons

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It’s good you managed to get your Podpoint inside your garage. 👍

The vine is going if it poses an issue. It was the only practical location for the charger as there is a door on the left.