Protection Principles
This page has not yet been technically reviewed by a qualified person. Always check the current standard and your own appointment (aanwijzing); this is not a substitute for NEN 3140 or NEN 1010.
§131 — Protection Principles
NEN 1010 Chapter 1, §131 describes the fundamental principles for the protection of persons, animals, and property against electrical hazards.
Three Pillars
- Protection against electric shock (§131.2) — direct and indirect contact.
- Protection against thermal influences (§131.3) — fire and burns caused by overcurrent.
- Protection against overcurrent (§131.4) — short circuit and overload.
Three Levels of Protection Against Electric Shock
For protection against electric shock (§131.2), NEN 1010 applies a layered model of three independent levels that complement rather than replace each other:
| Level | Purpose | Example measures |
|---|---|---|
| Basic protection | Prevents contact with parts that are live under normal operating conditions | Insulation of conductors, enclosures (IP rating), barriers |
| Fault protection | Prevents danger in the event of a single fault (e.g. breakdown of basic insulation) | Automatic disconnection of supply (AUV, §411), Class II equipment (double insulation), SELV/PELV, isolating transformer |
| Additional protection | Extra safety net when basic and fault protection fall short or fail | 30 mA residual current device (RCD), equipotential bonding |
These three levels are cumulative: an installation with only additional protection (an RCD) but without proper basic and fault protection does not comply with NEN 1010 — the RCD is a last line of defence, not a substitute for correct insulation and AUV.
Practice
- Every installation must make a deliberate choice between IT, TT, TN-S, TN-C, and TN-C-S systems.
- A 30 mA residual current device (RCD) is mandatory in Dutch dwellings (§411.3.3).
- Selectivity between fuses is covered in §536.
Next step: read §411 for the implementation of automatic disconnection of the supply (AUV).
Further reading
- §445 (IEC 60364-4-45)§445 — Protection against unintended automatic restart after undervoltage
- §543 (IEC 60364-5-54)Sizing the protective conductor — the adiabatic formula versus the simplified table
- IEC 60364-5-56 / NEN-EN 81-20 / NEN-EN 81-50Lift installations — supply, bonding and RCD protection of passenger lifts
- §413.3Electrical separation (§413.3) — an isolating transformer as a protective measure without earthing
- §423 (IEC 60364-4-42)§423 — Protection against burns: maximum accessible surface temperatures (Table 42.1)
- Bijlage A (IEC 60364-4-41)Annex A — Basic protection against direct contact, IP2X and the jointed test finger