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Low current, high current and older equipmentSame reading, different verdict. How?

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Low current and high current

TestCurrentBest for
Low current20–200 mAMost class I equipment
High currentUp to 25 AWhere a low-current result can't be trusted
✋A low-current test can give an unreliable result on a painted or powder-coated surface. You must get the probe onto clean, bare metal. If you can't, the result means nothing.

Section 10 · low current (20–200 mA) and high current (up to 25 A) continuity testing · p.70

Older equipment and the 0.5 Ω allowance

§Some older equipment reads slightly above Table 10.1. A higher value of up to 0.5 Ω in total — equipment plus supply cable — is acceptable, provided the inspector is satisfied the higher resistance is down to the design of the equipment and not deterioration of the earth connection.
✋0.5 Ω is the ceiling, cable included. Not 0.5 Ω plus the cable. Above 0.5 Ω, the allowance doesn't apply.

Which makes the asset register part of the test. The same 0.45 Ω reading means two different things:

✗Bought in 2024
0.45 Ω on a nearly-new appliance is a problem. Fail it, quarantine it, send it back.
✓Bought in 2010
Same reading, sixteen-year-old equipment, cable in good condition — acceptable.
Which is why you ask for the asset list. Without knowing the age, you can't apply this allowance. Ask the duty holder how long they've had it and when it went on the register.

Table 10.1 · Note 2 · older equipment

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