PELV
Protective Extra-Low Voltage
An extra-low- system fed from a safety source like , but with one point deliberately connected to earth. The earthed reference suits control circuits and electronics that need it, at the cost of losing SELV's complete separation — the difference between the two is a reliable exam question.
Where PELV fits in the learning path
The Installation section covers these units:
- Wiring Systems & Enclosures
- Cable Selection & Circuit Design
- Earthing, Bonding & Consumer Units
Curriculum mapping: C&G 2365 Units 203/204/305.
See this section in the full curriculum
This section is on the Plus path. Lesson availability depends on content review and your learning path.
Read, practise, return
1. Read it in context
- C&G 2365 Level 2Sparks Basics
2. Try recalling, then explore practice
Use the memory prompt below to connect the vocabulary.
- Electrical Science — quiz previewFree · Electrical Science
3. Return to the meaning
After reading or practising, explain the idea in your own words. Revisit the PELV definition to check what you remembered.
Recall a related term
Which term fits this definition? Say it to yourself, then reveal it. This is a memory prompt, with no score or saved result.
An extra-low-voltage system supplied from a safety source such as an isolating transformer, kept electrically separate from earth and from every higher-voltage system. Because the voltage is low and there is no path back to earth, touching one conductor cannot drive a dangerous current through you — the classic protective measure for shaver sockets and garden lighting.
Compare related terms
Open a meaning to compare its role with PELV, or follow its full entry.
SELV — Separated Extra-Low Voltage
An extra-low-voltage system supplied from a safety source such as an isolating transformer, kept electrically separate from earth and from every higher-voltage system. Because the voltage is low and there is no path back to earth, touching one conductor cannot drive a dangerous current through you — the classic protective measure for shaver sockets and garden lighting.
Read the SELV entryFunctional earthing
An earth connection made because equipment needs it to work — a clean signal reference for ICT and electronic systems — rather than for shock protection. It matters now because Amendment 4:2026 of BS 7671 updated the requirements around functional earthing for information and communication technology installations.
Read the Functional earthing entryA definition is a start. Using it in a real question is where it sticks.