OpenEVSE Kit Build Guide

OpenEVSE is a fully open-source EVSE (Electric Vehicle Supply Equipment) charging station designed by OpenEVSE and re-sold by OpenEnergyMonitor Store.

Nissan LEAF OpenEVSE

OpenEnergyMonitor have collaborated with OpenEVSE to improve energy monitoring integration and control as well as tailoring the setup for use in Europe and the UK. This page provides Europe / UK specific setup instructions and considerations.

See our blog post detailing a full OpenEVSE build review, and usage.

The standard build guide from OpenEVSE can be followed taking into account the specific OpenEnergyMonitor (Europe / UK) considerations (see below):

Kit contents.
An assembled OpenEVSE unit. LCD, push button and WiFi module are attached to the EVSE enclosure cover, not shown.

Specific considerations for OpenEVSE units obtained via the OpenEnergyMonitor Shop to be installed in Europe / UK.

1. EV Connector Cable Wiring

The EV cables from the OpenEnergyMonitor shop (Type 1 & Type 2) are wired as follows:

All connections in EVSE should be made using bootlace ferrules crimped terminals. This is especially essential for EV cables since they use fine stranded wire for increased flexibility. This fine stranded wire is susceptible to creeping out of a terminal due to thermal cycling resulting in possible overheating. See this Schneider Electric Data Bulletin.

EVSE cables obtained from the OpenEnergyMonitor shop will be pre-equipped with bootlace ferrules crimped terminals connections.


2. EVSE Mains Wiring

Mains wiring should only be undertaken by a qualified electrician.

In the UK / Europe an EVSE must be directly wired into a consumer unit using appropriately sized wiring and an RCD circuit breaker e.g. RCBO. The wiring and circuit breaker should be sized for maximum rating of the EV/EVSE and tethered cable, 6mm CSA wire is appropriate for 32A.

The max current of the EVSE should be set to match the continuous current rating of mains wiring in the OpenEVSE settings (via LCD menu) on first power up before connecting an EV (Setup > Max Current >).

In the USA / Canada you may see photos of the EVSE plugged into a wall-outlet, this is a NEMA 14-30 plug commonly used for electric clothes dryers, etc. These plugs don’t exist in the UK. The UK uses BS1363 3-pin plugs rated to 13A max (10A continuous).

Do not wire an EVSE into a 3-pin BS1363 plug unless the charging current is limited to 10A. This defeats the point of using an EVSE; better to use a portable EVSE ‘granny cable’ instead.

In mainland Europe Schuko plugs are rated to 16A max (10A continuous).

3. Charging Level

The OpenEVSE unit should be set to L2 (Level 2) charging mode (240V). This should be default setting for OpeneVSE running EU firmware. The charging mode can be set via the LCD menu:

Setup > Charging Mode > L2

Level 2 charging refers to charging from 220v-240v, as opposed to level 1 charging from 110v.

See User Guide video at the bottom of this page for a overview of how to operate the unit.

4. GFCI Test Enabled

All OpenEVSE’s from OpenEnergyMonitor contain hardware for GFCI (ground fault interruption) continuous monitoring of ground faults. See safely features section above. GFCI test should always be enabled in the LCD menu.

Hardware User Guide

Software User Guide

OpenEVSE units have been designed to exceed the safety requirements for EV Charging Stations from SAE J1772, NEC, UL and CE. Before supplying power to the car (and continuously while charging) the EVSE unit conducts a number of checks, no power is supplied until all the checks have passed. See

Mains wiring should only be undertaken by a qualified electrician.