The IP Protection Classification System

This is a system produced in IEC publication 529 which provides a means of specifying an enclosure on the basis of degree of protection. It does not provide for protection against mechanical damage caused by or within a device. NEMA Publication 250 does test for environmental conditions, such as corrosion, icing and oil. As there are differences in these methods of test and definition there cannot be exact equations between the IEC and NEMA classification codes, but because NEMA meet or exceed the IEC test requirements a cross reference can be made from NEMA to IEC. Figure 1, below is a conversion of NEMA type numbers to IEC classifications, it cannot be used as a conversion of IEC to NEMA classifications.

The tabulation, figure 2, is intended as a guide to determine or select an enclosure code using the IP system. For notation the letters IP are followed by two numbers. The first number is an indication as to the degree of protection to solid foreign objects, i.e. dust or fingers. The second number indicates the degree of protection to ingress of fluids, i.e. water.

Figure 1

Figure 2
NEMA Type Number IEC Classification
1 IP10
2 IP11
3 IP54
3R IP14
3S IP54
4 and 4X IP56
5 IP52
6 and 6P IP67
12 and 12X IP52
13 IP54
FIRST NUMBER SECOND NUMBER
Protection against solid objects Protection against liquids
  • 0 - no protection
  • 1 - protected against solid objects up to 50mm i.e. accidental touch by hands.
  • 2 - protected against solid objects up to 12mm i.e. fingers.
  • 3 - protected against solid objects over 2.5mm (tools & wires).
  • 4 - protected against solid objects over 1mm (tools, wires & small wires).
  • 5 - protected against dust-limited ingress (no hurmful deposit).
  • 6 - totally protected against dust
  • 0 - no protection
  • 1 - protected against vertically falling drops of water i.e. condesation.
  • 2 - protected against direct sprays of water up to 15o from the vertical.
  • 3 - protected against sprays to 60o from the vertical.
  • 4 - protected against water sprayed from all directions - limited ingress permitted.
  • 5 - protected against low pressure jets of water from all directions - limited ingress permitted.
  • 6 - protected against strong jets of water i.e. for use on ship decks - limited ingress permitted.
  • 7 - protected aganst the effects of immersion between 15cm and 1m.
  • 8 - protected against long periods of immersion under pressure.