Best practice for testing EV charging points

10-02-2021

Don’t miss out on a great business opportunity: make sure you’re properly equipped for testing electric vehicle charge points, says Peter Wade  of Megger.

In the last five years electrical vehicle technology has made major inroads into the transport market and it is a certain bet that, within a decade, electric vehicles (EVs) will become ubiquitous on the nation’s streets. A limiting factor on EV growth, however, is that charging points are sometimes few and far between, leading drivers to worry about where and when they’ll next be able to recharge! As a result, there is a strong demand for new EV charging points both for public use and in private homes, which has led to this becoming one of the fastest growing areas of business for electrical contractors.

As would be expected, there are stringent requirements for the electrical protection built into charging points. The basic requirements, prescribed by the IET Wiring Regulations, are that the charging point should be protected at the circuit source, or integrally in the charging point at the incoming supply position, by a Type A RCD/RCBO and that there should be provision for the supply to be disconnected automatically in the case of a DC fault current above 6 mA.

Detailed requirements relating to EV charging points which are contained in IEC 61851-1:2017, Electric vehicle conductive charging systems – Part 1:  General requirements and IEC 60364-7-722:2018 Low-voltage electrical installations – Part 7-722: Requirements for special installations or locations - Supplies for electric vehicles. Any contractor with the intention of tapping into the potentially lucrative EV charging point installation/testing market should, as their first step, ensure that they are fully up to speed with these requirements.

Their second step should be to ensure that they have appropriate test equipment to confirm that the requirements are being met in practice. Testing will always be needed on newly installed charging points, and may also be required later as part of a routine inspection and test or if a fault is suspected at any time.

Some modern multifunction installation testers, such as the Megger MFT1741+,  have the necessary functions needed for testing EV charging points, but they cannot be used on their own to carry out the full range of tests. This is because, in order to test a charging point, it is necessary to simulate the connection of a vehicle.

In particular, the person carrying out the test must be able to trigger the charging process by supplying the charging point with the appropriate combination of proximity pilot (PP) and control pilot (CP) signals. To make this possible, and to facilitate the connection of the test equipment to the charge point, test equipment manufacturers have introduced adapters, such as the Megger EVCA210-UK, specifically designed for EV charging point testing.

In general these adapters are supplied with a Type 2 plug for charging points that have a tethered or panel mounted Type 2 socket outlet, which is by far the most common. However, some manufacturers also offer a Type 1 plug, such as the Megger EVCA210-UK, to cater for charging points with a Type 1 socket. The most common vehicle requiring this would be the Mitsubishi PHEV. Be careful though, not all adapter manufacturers include the Type 1 plug as standard!

Features that users should look for on an EV charging point adapter include selection switches for CP and PP state signal adjustment, push-buttons to simulate CP errors and earth faults to ensure that the output of the charging point is correctly and safely disconnected and a manual PE pre-test. This ensures there are no dangerous voltages present on the PE conductor.

Finally, with single and three phase charging points available it is advantageous if the adaptor makes provision for test instruments to be connected using not only a mains socket, but also 4mm connection ports for L1, L2, L3, N, PE. Ideally, additional connection points should also be available for accessing the CP signal so that this can, if necessary, be monitored with an oscilloscope as an aid to fault finding.

The Megger EVCA210 incorporates all the above features.

According to energy supplier EDF, there are at present 30,000 public EV charging points across the UK, with 10,000 having been added in 2019 alone. The rate of expansion can be confidently expected to grow, which means that installing and testing EV charging points is an excellent business opportunity for electrical contractors. Operating effectively and efficiently in this growing, but competitive market, depends on having the right tools for the job – and that includes reliable, versatile test equipment.