Around a live part there are two zones: the danger zone, where an unprotected worker may suffer an arc or a contact, and the proximity zone, from which they could enter the first one by accident (annex I, points 7 and 11).
| Installation voltage | Danger zone (no lightning risk) | Proximity limit (if it cannot be marked out) |
|---|---|---|
| Up to 1 kV (low voltage) | 50 cm | 3 m |
| 20 kV | 60 cm | 3 m |
| 132 kV | 110 cm | 5 m |
| 380 kV | 250 cm | 7 m |
The guide recommends that anyone who is not an authorised worker stays outside the proximity limit (DPROX-2, the last column).
What is not for you if you are not authorised (annex V)
- Entering electrical service rooms (substations, control rooms) unless an authorised worker supervises you and you have been informed of the risks.
- Opening switchboards, cabinets and enclosures of electrical equipment.
- Bringing ladders, metal scaffolding, long pipes or profiles, cranes or platforms close to an overhead line without a prior study: these cause the most accidents (table 5 of the guide).
In practiceYou are going to prune a tree next to a power line with an aluminium ladder.
Before starting, the line and its voltage must be identified; if it cannot be switched off, the area is marked out and the
work keeps the distances in the table.
Source: Real Decreto 614/2001, sobre protección frente al riesgo eléctrico (Royal Decree on protection against electrical risk; consolidated text, in Spanish), annex I, points 7 and 11, table 1, and annex V · INSST, Guía técnica para la evaluación y prevención del riesgo eléctrico (technical guide, 2020, in Spanish), comments on annex V, table 5