IP Ratings and NEMA protection

Ingress Protection (IP) ratings (described in IEC 60529) specify the environmental protection an enclosure provides.

The IP rating normally has two numbers.

The first number specifies the protection from solid objects or materials.

The second number specifies the protection from liquids.

IP Protection Number Summary

FIRST NUMBER - Protection against solid objects

0 = No protection

1 = Protected against solid objects up to 50mm e.g. accidental hand contact

2 = Protected against solid objects up to 12mm e.g. fingers

3 = Protected against solid objects up to 2.5mm (tools and wires)

4 = Protected against solid objects up to 1mm (small tools and wires)

5 = Protected against dust, limited ingress (no harmful deposit)

6 = Totally protected against dust.

SECOND NUMBER - Liquid protection

0 = No protection

1 = Protection against vertically falling drops of water e.g. condensation

2 = Protection against direct sprays of water up to 15 degrees from vertical

3 = Protection against direct sprays of water up to 60 degrees from vertical

4 = Protection 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 low pressure jets of water (such as use on ship decks) - limited ingress permitted.

7 = Protected against the effect of immersion between 15cm and 1m.

8 = Protected against long periods of immersion under pressure

So IP65 means the enclosure protects against dust and low pressure water jets sprayed from all directions. It does allow some water to enter the enclosure, provided the amount is not harmful to the equipment inside.

THIRD NUMBER (often omitted) - Impact protection

0 = No protection

1 = Protection against 150g falling from 15cm height (0.225 Joules)

2 = Protection against 250g falling from 15cm height (0.375 Joules)

3 = Protection against 250g falling from 20cm height (0.5 Joules)

4 = Protection against 500g falling from 40cm height (2.0 Joules)

5 = Protected against 1500g falling from 40cm height (6.0 Joules)

6 = Protected against 5kg falling from 40cm height (20.0 Joules)

NEMA comparisons

The NEMA rating system can be compared to the IP system. The most common NEMA ratings are:-

NEMA 1 Similar to IP30. Protects against limited amounts of falling dirt in indoor installations.

NEMA 2 Similar to IP55. Protects against circulating dust, falling dirt and dripping non-corrosive liquids in indoor installations.

NEMA 13 Similar to IP65. Protects against dust, sprayed water, oil and non corrosive coolants in indoor installations.

NEMA 4 Similar to IP65. Protects against wind-blown dust and rain, splashing water, hose-directed water and damage from external ice formation in indoor and outdoor installations.

NEMA 4X Similar to NEMA4 but also protects against corrosion

NEMA 6 Similar to IP67

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