EV Charging and Maximum Load on Single Phase in the UK Guide

EV charging draws more power than the AC or induction cooker at your home. So, you got to be careful while plugging your EV at a home charging station.

There is a possibility that you may exceed the maximum allowable load. Especially considering that house supply runs on a single phase in the UK.

We will discuss the maximum load on a single phase in the UK when it comes to EV charging. So, without further ado, let’s start!

What is the Maximum Load on a Single Phase in the UK?

Depending upon the size of the supply fuse and the capacity of your distribution system, the maximum load on a single phase in the UK can be 14.4 kW, 19.2 kW, and 24 kW. The maximum current rating for each of these cases is 60A, 80A, and 100A at 240V, respectively.

Typically a modern-built house in the UK is equipped with a 100A main supply fuse. So, ideally, you have 24 kW of power supply at your disposal. But that is not the case in a real-life setting. You must account for line losses, voltage drops, and the efficiency of individual appliances.

Why is Maximum Load on a Single Phase Important for EV Charging?

EV chargers draw more power than any other individual electrical appliance at your home. Thus, there is a high possibility that you might exceed the maximum load for a single phase while charging the EV. This may result in a power outage, permanent damage to your house wiring, and damage to the charging infrastructure of your EV.

EV chargers can draw somewhere between 3 and 9 kW of electrical power while charging. Some fast chargers rated for 50 amps or 60 amps might draw up to 12 kW power. If a single appliance is drawing more than 50% of the total available power, then you must be careful.

Things can get even tighter if your house has an older electrical distribution system with a 60A fuse and 14.4 kW maximum load capacity. You won’t be able to turn on any other major electrical appliance while charging your EV.

Can You Charge an EV on a Single Phase in the UK?

Yes, you can charge an EV on a single phase in the UK. There is nothing to worry about if you live in a modern built house that has a 100 amp main power fuse. If the maximum load capacity of the distribution system at your house is 14.4 kW, EV charging is still possible. But you must not use an EV charger rated over 6 kW.

The answer to the question of whether you can charge an EV on a single phase in the UK will vary from situation to situation. Let’s discuss a few cases to set precedents for you to follow.

Case 1: Running an EV Charger, Induction Cooker, and AC

An induction cooker can draw somewhere between 3 and 4 kW, whereas an AC will draw 1-3 kW. So, even if your EV charger is rated for 50-60A (11-12 kW), you will have sufficient load room to operate the induction cooker and AC. The combined load of all three is 15 kW to 19 kW.

It is true for a house with a maximum load capacity of 24 kW and 19.2 kW. With a 19.2 kW capacity system, you’re running close to the sun. But considering that AC only draws power in excess of 2 kW while starting up and EVs use less power towards the later end of their charging cycle, there should not be any problem whatsoever.

However, running all these appliances with a system of 14.4 kW capacity might not be a good idea. Either you have to upgrade the system or limit the charging power to 3 or 6 kW. Only then it will be safe to charge your EV at home.

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Case 2: Running Two EV Chargers Simultaneously

Isn’t it enough to charge one EV at the house that you have to charge two at a time? It is never a good idea to charge two EVs simultaneously in a house with a single-phase electrical system. There is no question of plugging two fast chargers drawing 60 A current each. Even a 100 amp system will not be able to endure this load if you switch off every other appliance at home.

A smaller charger with 30-40A can be plugged simultaneously into a 100A system. But I won’t recommend that. It leaves very little load room for other electrical appliances. There isn’t only an induction cooker and AC at the house. There are several other small load-drawing appliances.

Case 3: Running an EV Charger for 30-40 hours

Another problem with EV charging is that they are used over a period of several hours that too continuously. Now, theoretically, there is nothing wrong with using an appliance for several hours. The only thing you got to worry about is the integrity of the wiring and distribution system.

Normally, a home EV charger takes somewhere between 8-10 hours, while some can take 30-40 hours. But if a charger is taking this long to charge, high chances are that it is rated for less load between 3-6 kW. There shouldn’t be a problem if this much power is drawn for 30-40 hours.

Also read: EV Battery in Hot Temperature: 5 Things to Know

Is it Safe to Charge an EV on a Single Phase in the UK?

Yes, it is safe to charge an EV on a single phase in the UK. Modern-built houses have a maximum load capacity of 24 kW, whereas a fast EV charger draws up to 12 kW of power. This leaves room to run other electrical appliances, such as an induction cooker or AC.

Though you should avoid having multiple car charging ports at your home, plus, if you’re going to own an EV, charging is going to be an ongoing affair. I recommend upgrading the electrical system of your house to 100 amps. This would give you enough power to run all the major electrical appliances with an EV charger.

I hope this article was helpful in determining the maximum load on a single phase in the UK. What are your thoughts on this matter? Let us know in the comments below!


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