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Proving dead: the three tests, and the rhythmWhich conductor does the first probe go on?

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Put the probe on the conductor that should be at zero volts first — the neutral or the earth — and bring the second probe onto what would be live if it had not been isolated. No regulation says so. The reason is in your hand: do it the other way round and the free end of your lead is sitting on a line conductor while you are still reaching with it. Work from the least dangerous conductor first. The CPC is the safest, so that is where you start, and you move one probe at a time.

#Single phase — three tests
1CPC — Neutral
2CPC — Line
3Line — Neutral
Move one hand at a time. Never cross your arms over. Start on the safest combination and work along. Get a rhythm going and it is quicker — and you are not reaching across live terminals to do it.

Three phase is the same idea, ten readings: four to earth, three to neutral, three between lines. Start on earth, the safest conductor, and the line-to-line tests come last, because they are the most dangerous. Work up the list, not down it.

GroupThree phase — ten tests
1–4Earth to Neutral · Earth to L1 · Earth to L2 · Earth to L3
5–7Neutral to L1 · Neutral to L2 · Neutral to L3
8–10L1 to L2 · L1 to L3 · L2 to L3 — last

Lead colour does not matter on safe isolation or on dead testing. On live testing you line your colours up with the conductors. On phase rotation the order genuinely matters.

1–4  Earth to everything EN EL1 EL2 EL3 5–7  Neutral to each line NL1 NL2 NL3 8–10  Line to line — LAST L1L2 L1L3 L2L3 4 + 3 + 3 = 10 readings
Ten is easy to lose count of, so count it in groups: four off the earth, three off the neutral, then three between lines. The order is not arbitrary — you work out from the safest conductor, which is why the line-to-line tests are last. One probe moves at a time, and your arms never cross.

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