Classification of luminaire enclosures
The resistance of electrical equipment and devices to harmful effects of the weather and environment, as well as the protection against accidental contact with live parts depend on the execution of enclosures and guards.
This kind of protection is referred to as ingress protection and denominated by the so-called IP ratings. According to this classification, electrical enclosures are marked with a two-digit code preceded by the letters IP (PN-EN 60529:2003).
AC electric appliances operating at a rated voltage of up to 440V and the voltage to ground not exceeding 250V, depending on the applicable electric shock protection measure, are divided into the following protection classes:
Protection class 0 – Protection against electric shock relies on basic insulation only.
If the insulation is damaged, electric shock protection should be ensured by favourable conditions, such as: placing out of reach, isolation of the workplace, no earthed devices, systems or structural elements within arm’s reach.
In Poland, the use of Class 0 equipment is permitted as long as there is no simultaneous contact with the appliance and earth potential or if the contact is rare.
Protection class I – Protection against electric shock by indirect touch is ensured by connecting a protective conductor terminal with a PE or PEN conductor, or directly with the earthing system.
This is to ensure:
- Fast enough activation of relevant protective devices and disconnection of the power supply, or
- Limitation of touch voltage to values which do not exceed the permissible limits under specific conditions.
Protection class II – In the appliances of this class electric shock protection is ensured by the application of suitable insulation – double or reinforced – whose damage is very unlikely.