In Non-Hazardous Locations, the specific enclosure types, their applications, and the environmental conditions they are designed to protect against, when completely and properly installed, are as follows:
NEMA 13 Enclosures
Constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and circulating dust, lint, fibers, and flyings); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (dripping and light splashing); and to provide a degree of protection against the spraying, splashing, and seepage of oil and non-corrosive coolants.
The IP Code (or International Protection Rating, sometimes also interpreted as Ingress Protection Rating*) consists of the letters IP followed by two digits and an optional letter. As defined in international standard IEC 60529, it classifies the degrees of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in electrical enclosures. The standard aims to provide users more detailed information than vague marketing terms such as waterproof.
The digits (characteristic numerals) indicate conformity with the conditions summarized in the tables below. For example, an electrical socket rated IP22 is protected against insertion of fingers and will not be damaged or become unsafe during a specified test in which it is exposed to vertically or nearly vertically dripping water. IP22 or 2X are typical minimum requirements for the design of electrical accessories for indoor use.
*Explanation of the letters IP is given in IEC 60529 (Ed. 2.1), clause 4.1
First Digit: Solids
The first digit indicates the level of protection that the enclosure provides against access to hazardous parts (e.g., electrical conductors, moving parts) and the ingress of solid foreign objects.
Object size protected against
No protection against contact and ingress of objects
Any large surface of the body, such as the back of the hand, but no protection against deliberate contact with a body part.
Fingers or similar objects.
Tools, thick wires, etc.
Most wires, screws, etc.
Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment; complete protection against contact.
No ingress of dust; complete protection against contact.
Second Digit: Liquids
Protection of the equipment inside the enclosure against harmful ingress of water.
Object size protected against
Dripping watter (vertically falling drops) shall have no harmfull effect.
Dripping water when tilted up to 15°
Vertically dripping water shall have no harmful effect when the enclosure is tilted at an angle up to 15° from its normal position.
Water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect.
Water splashing against the enclosure from any direction shall have no harmful effect.
Water projected by a nozzle (6.3mm) against enclosure from any direction shall have no harmful effects.
Powerful water jets
Water projected in powerful jets (12.5mm nozzle) against the enclosure from any direction shall have no harmful effects.
Immersion up to 1m
Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).
Immersion beyond 1m
The equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. Normally, this will mean that the equipment is hermetically sealed. However, with certain types of equipment, it can mean that water can enter but only in such a manner that it produces no harmful effects.