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Safe isolation on a periodic, and whether it can be done entirely deadWhich regulation covers working live?
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The question at the end: Which regulation covers working live? The answer is in the notes below.
The notes
Exactly as they are on the site.
Safe isolation comes first
Before any testing, the installation or the part of it you are working on is isolated and proved dead. The reason is legal as much as practical.
| Regulation | What it does |
|---|---|
| EAWR · Reg 4 | Systems to be constructed and maintained to prevent danger, so far as is reasonably practicable |
| EAWR · Reg 4(3) | Maintenance work itself to be carried out in a manner that prevents danger |
| EAWR · Reg 14 | Live working — the three conditions, all of which must be met |
| EAWR · Reg 29 | The defence: having taken all reasonable steps and exercised all due diligence |
Regulation 14's three conditions, all of which must be satisfied before live working is justified:
| 1 | It is unreasonable in all the circumstances for the conductor to be dead |
| 2 | It is reasonable in all the circumstances to be at work on or near it while live |
| 3 | Suitable precautions are taken to prevent injury — including, where necessary, suitable protective equipment |
Can a periodic be done entirely dead?
No — and it is worth understanding exactly why, because it is the clearest everyday use of Regulation 14.
| Live test | Could it be avoided? | How |
|---|---|---|
| Ze | Yes | Can be enquired of the DNO |
| Zs | Yes | Can be calculated — Ze + (R1+R2) |
| Ipf | Yes | Can be enquired or calculated |
| RCD test | No | There is no way to prove a trip time on a dead circuit |
An RCD operates on an imbalance of current between line and neutral, not on potential difference. There has to be current flowing for there to be an imbalance to detect — so the circuit has to be live and complete. Test at the furthest outlet where practicable.
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- 18th Edition
- Building Regs
- PAT
- Fundamental Inspection & Testing
- Initial Verification
- Periodic Inspection & Testing