Free notes
Testing an extension lead and lead setsSix sockets. How many continuity readings?
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Exactly as they are on the site.
Earth pin of the plug to the earth contact of every socket on the lead. A socket adapter makes it easy.
Readings along the lead
Socket 1 0.04 Ω furthest from the flex ... 0.03 Ω Socket 6 0.02 Ω nearest the flex: less cable, lower reading
The switches don’t matter for continuity — the earth isn’t switched. They do for insulation resistance: on, then L + N to earth at each socket, minimum 1 MΩ.
- On a PAT tester, the lead loops back into the tester and its cord test does continuity, insulation and polarity in one go.
- IEC leads — the ones people call kettle leads — are tested individually, the same way. Schools keep boxes of them.
- A surge-protected lead has electronics built in: 250 V, not 500.
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- 18th Edition
- Building Regs
- PAT
- Fundamental Inspection & Testing
- Initial Verification
- Periodic Inspection & Testing