Information
Definition
TT earthing is an arrangement where the installation uses its own earth electrode rather than relying on the distributor's protective conductor. It is normally assessed during product selection, circuit design, installation verification and maintenance of EV charging equipment.
Why it matters
It can be relevant for EV charging where PME risks must be avoided or where site conditions require a separate earthing arrangement. For UK users, it supports safer specification decisions and reduces the risk of misunderstanding how a charger should be protected or installed.
References
Standards and regulations
BS 7671
BS 7671 is the UK national standard for electrical installations, covering the design, erection, inspection, testing and verification of low-voltage electrical systems. Section 722 contains specific requirements for supplies to electric vehicles.