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Phase sequence: you do not need a special instrumentDo you need a special instrument?
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Guidance Note 3 · p.93. Phase sequencing is done at each point of the installation, to confirm every conductor is in the right place.
| Method | How |
|---|---|
| By inspection | Brown lands where brown belongs, through the busbar, at every point |
| By continuity | With the circuit isolated, test between two line conductors as you would an R1 + R2, then the next pair, then the last |
| With an AVI | The rotation test — below |
The probe sequence
The two probe tips are labelled L1 and L2. 1. L1 probe → L1 L2 probe → L2 2. L1 probe → L2 L2 probe → L3 3. L1 probe → L3 L2 probe → L1 You want the R arrow lighting up on all three.
✋The AVI rotation check is a live test. You are working on a live three-phase board. Treat it accordingly. Only the continuity method is done dead.
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- 18th Edition
- Building Regs
- PAT
- Fundamental Inspection & Testing
- Initial Verification
- Periodic Inspection & Testing