What is RCD and Why is it Essential for Charging With the go-e Charger?

The same electricity you use to recharge your car battery or heat the boiler in your house can be unpredictable and even hazardous if not properly controlled. A simple electrical fault like a broken wire, for instance, can cause serious issues – it’s like playing with fire, sometimes quite literally. Issues of this nature are normally arising from the electric vehicle itself.

But how can you protect yourself?

When it comes to home EV charging, you need protection from two types of current - DC (direct current) and AC (alternating current). Our go-e Charger provides safety with features like the DC protection module, which shuts down the charger during DC fault currents. It also has an additional AC detection integrated. 

However, for this system to function, you’re obliged to have an RCD (Residual Current Device) type A installed on the building's side. Keep in mind that the local installation regulations must be observed. In this blog post, we'll explain what an RCD type A is and why it's a crucial addition to ensure your safety.

An RCD, short for Residual Current Device, is a critically sensitive safety mechanism that serves as a safeguard against electrical mishaps. 

The main purpose of RCD is to automatically cut off electricity in the event of a fault, a function that can be genuinely life-saving. This rather innovative device comes to your rescue when you encounter live electrical elements like exposed wires, shielding you from potentially fatal electric shocks.

To illustrate the indispensable role of RCDs, let’s take a real-life situation without their protective presence. Imagine, a damaged extension cord goes unnoticed, and someone accidentally touches it. In the absence of an RCD, the electricity would flow unchecked through their body, leading to severe injury or even fatality.

Residual current devices offer an extra level of protection beyond the integrated protective measures that the appliances and devices powered by mains already have.

The way an RCD works is by carefully watching the flow of electricity in a circuit.  Inside, it features coils of wire wrapped around a ferrite toroid core. There's a separate coil for each live wire in the circuit it's protecting. 

Here’s RCD in action:

1. When the RCD senses that something isn't quite right with the flow of electricity, i.e. when the current isn't balanced between the different live wires, it creates a kind of electrical signal in one of its coils, which we call the "tripping coil." 
2. This signal acts like an alarm, telling the parts of RCD that there might be a problem.
3. In response to this alarm, the RCD instantly stops the flow of electricity to the circuit it's guarding. 

This fast reaction is crucial because it can be the difference between staying safe and being in danger.

What do you actually need protection from? Earth faults, also called ground faults, occur when electricity escapes from its proper path and goes into the ground or other unintended places. This can happen for several reasons:

• Insulation problems: The most common reason for earth faults is when the protective covering around an electric wire starts to wear out or gets damaged. This makes it easy for electricity to escape into the ground.
• Environmental issues: Things like moisture, humidity or dirt can penetrate wire insulation if exposed to it for a long time or get into electrical outlets creating faults.
• Improper wiring: If the electrical system is set up incorrectly or done poorly, it can make earth faults more likely.
• Equipment troubles: If electrical devices or their parts are not working properly, they might create paths for electricity to escape into the ground or energise metal surfaces to hazardous voltages.

RCDs come in different types, each specifically tailored for distinct electrical devices. Type A RCDs can be used for a diverse array of appliances, including inverters, induction hobs, electric vehicle charging equipment, power supplies, IT equipment, as well as lighting equipment like dimmers and LED drivers. 

The go-e Charger Gemini as well as Gemini flex comes with an integrated DC protection module for detecting DC faults and offers additional AC detection that identifies currents from 6 mA for DC and 20 mA for AC. Nevertheless, to ensure safety during charging, specific components are required.

For safe operation, you must install an RCD Type A on the building side. This type, designed to rapidly detect and respond to AC residual currents, offers sufficient protection against electrical faults. Even though the DC protection module provides additional AC detection, some extra safety rules must be followed. Why? Because of specific safety standards. They state that a Type A RCD must be used as it has a special design with a lever and indicators to show if they're working correctly. 

In addition to the RCD Type A, you (or rather your electrician) need to incorporate a miniature circuit breaker in the electrical system. This breaker acts as a secondary protective measure, disconnecting the power supply in case of a fault to prevent electrical hazards or damage to the charging equipment.

An RCD continually monitors the electrical current within the circuits it is meant to protect. Should it detect electricity travelling through an unintended path, like a person touching a live part, the RCD swiftly cuts off the circuit, substantially minimising the chances of fatal injuries or severe harm.

The LEDs around the charger port are your indicators. They will flash red at the top and turn pink at the bottom to let you know something's up. In this case, it means the go-e Charger spotted a DC fault current of >= 6 mA or an AC fault current of >= 20 mA. This can occur, for example, if there is excessive moisture on the charging cable connectors or the vehicle's Type 2 connector. Another reason could be that the car is asking for more charging current - certain car models produce very high DC fault currents when charging at lower amperage, so they start asking to be charged at higher power.

To acknowledge the fault, you can press "Reboot" in the app or give the Charger a quick power supply break. Normally, this fixes the situation. 

If things still seem off, you can decrease the charging current, but also check out the connection you're using. Another reason could be a defective charging system in your vehicle.