EV Charging at Home: All There Is to Know

EV chargers all have different voltages, currents, connections and modes. It’s good to know how EV charging at home works and at least some of the jargon.

New Zealand has a small but fast-growing electric vehicle (EV) fleet. These vehicles require “Electric Vehicle Supply Equipment” (EVSE) – that’s battery chargers, aka EV charging stations to you and me.

Different chargers have different voltages, currents, connections and modes. If you use an EV and charge it at home, it’s good to know at least some of the jargon…

EV charging at home: Mode 1

Domestic power point and extension cord

This is simply a standard power cord that plugs into a normal domestic 3-pin 10A socket. The maximum power is limited to 8A/2kW.

The charger in the vehicle converts AC to DC and controls battery charging.

Mass manufacturers no longer use this mode because the lead is always live. This form of charging is therefore actively discouraged in New Zealand. However, it is okay for e-bikes, e-scooters and the like.

If you need an electrician capable of wiring up an EV charging station at home, get in touch… Phone 0800 66-99-99 Email guy@complyguy.co.nz

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EV charging at home: Mode 2

Domestic power point and cable with protection

This charger type is simply a power cable that incorporates a protection device (blue) and is plugged into a power point at one end and an EV charging plug at the other end.

The protection device is known as an “In-Cable Control and Protection Device” (IC-CPD), and is either part of the cable or in a box mounted no more than 300mm from the 3-pin plug end.

This type of cable has the high-falutin’ name “Electric Vehicle Supply Equipment” (EVSE). In reality it’s nothing more than a power lead with automatic on/off functions controlled by the car. The on/off function ensures the lead is only live when the EV is charging.

The charger in the vehicle converts AC to DC and controls battery charging. As soon as the EV is fully charged, the car charger signals the control box which then disconnects power between the box and the car.

Because mode 2 EVSEs are plugged into a power point, they limit the current to a level that most power points can deliver. They do this by telling the EV to charge at a rate that is no greater than the pre-set limit in the control box. This is generally around 2.4kW (10A).

Notes:

1. The maximum current carrying capacity is 10A per phase.
2. Each socket-outlet should have an earthing contact connected to the protective earth conductor.
3. Electric Vehicle Supply Equipment at home should be supplied from a dedicated final sub-circuit.
4. It must be protected with the use of a 30mA Type B residual current device (RCD).
5. The socket outlet for the EV should be located as close as practicable to the vehicle’s charging location.
6. Each socket outlet installed for Mode 2 EV charging at home must comply with New Zealand standards and have the correct documentation to prove compliance.

All in-cable control and protection devices (IC-CPD) should:

1. Incorporate an RCD to provide protection against electric shock.
2. Provide protection against overload.
3. Be designed to operate at standard low voltage and a nominal frequency of 50 Hz and marked accordingly.
4. All functions of an IC-CPD should ‘fail to safety’.
5. Must not have damaged casing, leads or sockets.

If you need an electrician to wire up an EV charging station at home, we’d love to hear from you… Phone 0800 66-99-99 Email guy@complyguy.co.nz

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EV charging at home: Mode 3

Specific socket on a dedicated circuit

This is the most common type of charger for EV charging at home. A dedicated wall box with built-in control and protection electronics is plugged into the EV via its permanently-attached lead, or sometimes a socket outlet.

Mode 3 EVSEs (Electric Vehicle Supply Equipment) are often called an EV charger, but it’s still the charger in the vehicle that converts AC to DC and controls battery charging, same as mode 2 ESVEs. The wall box is just the home of the on/off electronics, which means it’s nothing more than a glorified automatic power point!

Charging rates include 3.6kW (16A, single phase) to 22kW (30A, 3-phase) and even 40kW (63A, 3-phase) depending on the specific EVSE chosen and EV charging capacity.

Older Nissan Leafs have a maximum charging rate of 3.6kW, while new Teslas can use anything up to 20kW!

This is the only charging mode that meets the applicable standards regulating electrical installations (IEC 61851). Because it has a dedicated circuit, it allows load shedding so that electrical household appliances can be operated during vehicle charging, or it can optimise the electric vehicle charging time.

Notes:

1. The minimum current carrying capacity for a single-phase Mode 3 charger in a domestic installation is 32 amps. Multi-phase units can be a minimum of 20 amps. The circuit must contain an isolating switch with a minimum 32A current rating complying with AS/NZS 3000 2.3.2.2.1, positioned adjacent to the charger.
2. Electric Vehicle Supply Equipment at home should be supplied from a dedicated final sub-circuit.
3. It must be protected with the use of a 30mA Type B residual current device (RCD).
4. The socket outlet for the EV should be located as close as practicable to the vehicle’s charging location.
5. The output socket or cable of the AC supply connection facility must be installed at a minimum height of 800mm from the floor or ground.
6. It must have the correct documentation to prove compliance in New Zealand.

If you need an electrician capable of wiring up an EV charging station at home, get in touch… Phone 0800 66-99-99 Email guy@complyguy.co.nz

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EV charging: Mode 4

Direct current (DC) connection for fast recharging

The electric vehicle is connected to the main power grid through an external charger, usually a wall box or pillar, which converts AC to DC.

Control and protection functions and the vehicle charging cable are installed permanently in the wall box or pillar.

It connects to the EV using a different socket, of which there are 3 main types, depending on the standard adopted by the manufacturer.

This type of charger is often referred to as ‘DC fast-charge’, or just ‘fast-charge’.

The charging rates for mode 4 vary greatly. At the low end are portable 5kW chargers right through to 50kW (CHAdeMO), 120kW (Tesla) and 150kW (CCS).

But wait, there’s more! Soon to be rolled out are 350kW and 400kW standards.

Given these widely varying charging rates for mode 4, there is some confusion as to what fast-charge really means.

Because this is a Direct Current (DC) system, at time of writing it is not available to domestic residences and is limited even at many businesses.

Mode 4 is mostly used for public charging stations where the infrastructure can allow for very fast charging options.

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Unsafe Practices and Conditions

The following are considered unsafe for the supply of electricity to an EV, or the use of Electric Vehicle Supply Equipment (EVSE)…

1. The use of any electric vehicle adaptor that is not specifically supplied by the vehicle manufacturer or by the EVSE manufacturer.
2. The use of a socket-outlet adaptor.
3. Cascading of two or more supply leads.
4. The use of an extension lead.
5. The use of portable socket-outlets including EPOD (Electrical Portable Outlet Device, e.g. multi-board) and PSOA (Portable Socket-Outlet Assembly, e.g. multi-board that includes an RCD and an overload circuit breaker as well as power points).
6. The use of a single socket-outlet for the supply of more than one vehicle at a time.
7. The use of an EVSE that is not labelled by the manufacturer as being compatible with a 230 volt, 50 Hz supply.
8. The supply of electricity to anything other than an EV from an IC-CPD or a charging station.

Any charging station or EVSE that is found to be unsafe at any time, or which is involved in an electric shock event, should be taken out of service immediately and not used until the charging station or EVSE is verified as safe.

All EVSE circuits for Mode 2 or 3 charging at home should contain RCD protection. The only currently recommended RCD is a Type B.

Hopefully this will help you decode some of the jargon as you do your research on EV charging at home.

If you need an electrician to wire up an EV charging station at home, we’d love to hear from you… Phone 0800 66-99-99 Email guy@complyguy.co.nz