From January this year, when the 18th edition wiring regulations came into force, there was a particular relevance for contractors working with installing and maintaining EV
charging points. Under the regulations charging points can be protected by either a RCD type B or an RCD type A and appropriate equipment that ensures disconnection of the supply in case of a DC fault above 6mA.
It is likely that contractors are going to be attracted to fitting car charging points with the latter type protection to avoid the need of using a more costly B type RCD. Previously, a DC current of around 6mA was used to lock A type RCDs to stop them from tripping during loop testing, so the 6mA DC current protection needs to be checked. Also in a recent survey, more than 50% of installers questioned said that they’d experienced RCD failure straight out of the box. It’s therefore essential that the whole system is checked on installation, as well as at intervals during the equipment’s lifetime.
Type B DC sensitive RCDs are rated at 30mA. They can be tested by a range of premium test equipment using various routines. However these testers are sometimes limited to a DC sensitivity in the region of 15mA and above.
So how do installers test the charge points with 30mA AC and 6mA DC protection (also known as type EV RCDs)?
Fortunately there is a solution. Metrel has developed the innovative EVSE Adapter A 1532
, which plugs directly into charge points, known as electrical vehicle supply equipment (EVSE) to the regulators, giving access without opening the box.
One of the immediate advantages is that the adaptor accesses the charge point in the same manner as an electrical vehicle and thus tests the system as a whole. It can test the charging point in all charging state outputs: disconnected, charge ready, active charging (with or without ventilation) and pilot error.
The MI 3152 touch screen installation tester
offers the 6mA DC test to confirm compliance with the new 18th Edition regulations. Programmable auto sequences cost-effectively help the engineer through all the required tests, and ensure they never again leave an installation without completing the full set of test results for certification and invoicing.
Find out more about the MI 3152 touch screen installation tester
This article first appeared on the website of Professional Electrician & Installer magazine on 29 January 2019.