外壳防护等级

外壳防护等级(IP)

仪表外壳防护等级(IP)代码(BS EN60529;1992),由字母IP和后续的两位特征数字表示。

例：

IP65 即要求具有尘密及对喷水的外壳防护功能

附加数字：防机械冲击

第三位特征数字（至ＥＮ标准中不包括），适合在某些欧

洲国家中通用（参阅法国标准ＮFＣ２０-０１０）：

IP外壳防护等级"接近等于NEMA防护等级：

IP codes

Degrees of Protection Provided by Enclosures

This standard describes a system for classifying the degrees of protection provided by the enclosures of electrical equipment. Developed by the European Committee for Electrotechnical Standardization (CENELEC), these standards are designed to numerically rate an electrical product on the level of protection its enclosure provides. By assigning different number codes, the product's degree of protection can be identified quickly and easily. In the code IP 54, for example, IP identifies this standard, the 5 describes the level of protection from solid objects, and 4 describes the level of protection from liquids.

International Protection (IP) Ratings

The IP rating system classifies the degree of protection from solid objects and liquids afforded by electrical equipment and enclosures. Recognized in most European countries and meets a number of British and European standards, this rating system includes: Classification of Degrees of Protection Provided by Enclosures, BS (British Standards) 5490:1977; IEC (International Electrotechnical Commission) 529:1976.

Specifications for Degrees of Protection of Enclosures of Switchgear and Control Gear for voltages up to and including 1000 VAC and 1200 VDC, BS 5420:1977; and IEC 144:1963.

First Number

Protection against solid objects

Second Number

Protection against liquids

0 no protection 1 protected against solid objects up to 50 mm (e.g. accidental touch by hands) 2 protected against solid objects up to 12 mm (e.g. fingers) 3 protected against solid objects over 2.5 mm (e.g. tools and wires)

4 protected against solid objects over 1 mm (e.g. tools and small wires)

5 protected against dust-limited to ingress (no harmful deposits) 6 totally protected against dust

0 no protection

1 protected against

vertically falling drops of water (e.g. condensation) 2 protected against

vertically falling drops of water up to 15° from the vertical

4 protected against water sprayed from all directions limited ingress permitted 6 protected against strong jets of water—limited

ingress permitted (e.g. for use on ship decks) 7 protected against the effects of temporary

immersion between 15 cm and 1 m

NEMA/IEC Enclosure Ratings

NEMA/IEC Enclosure Ratings Conversion of NEMA type classifications to IEC classification designation (IP ratings). Note: NEMA standards meet or exceed IEC standards; therefore, the conversion does not work in the opposite direction.

NEMA enclosure type no.

IEC enclosure class

NEMA definition

General-purpose. Protects against dust, light, and indirect splashing but is not dust-tight; primarily prevents contact with live parts; used indoors and under normal atmospheric conditions.

1 IP10

Drip-tight. Similar to Type 1 but with addition of drip shields; used where condensation may be severe (as in cooling rooms and laundries).

IP11

Intended for outdoor use. Provides a degree of protection against falling rain and ice formation. Meets rod entry, rain, external icing, and rust-resistance design tests.

IP14

Watertight (weatherproof). Must exclude at least 65 GPM of water from 1-in. nozzle delivered from a distance not less

4 and 4X

than 10 ft for 5 min. Used outdoors on ship docks, in dairies, and in breweries. 5

Dust-tight. Provided with gaskets or equivalent to exclude dust; used in steel mills and cement plants.

IP56

IP52

Hazardous. For indoor use in Class I, Groups A, B, C, and D environments as defined in the NEC.

Hazardous. For indoor and outdoor use in locations classified as Class II, Groups E, F, or G as defined in the NEC.

MSHA. Meets the requirements of the Mine Safety and Health Administration, 30 CFR Part 18 (1978).

General-purpose. Protects against the corrosive effects of liquids and gases. Meets drip and corrosion-resistance tests.

—

9 —

10 11

— —

General-purpose. Primarily used to provide protection against dust, spraying of water, oil, and noncorrosive coolants. Meets oil exclusion and rust resistance design tests.

13 IP54

National Electric Code (NEC) Ratings

Hazardous Classifications:

Class I: Areas in which flammable gases of vapors may be present in the air in sufficient quantities to be explosive.

Group A: Atmospheres containing acetylene

Group B: Atmospheres such as butadiene, ethylene oxide, propylene oxide, acrolein, or hydrogen (or gases or vapors equivalent in hazard to hydrogen, such as manufactured gas) Group C: Atmospheres such as cyclopropane, ethyl ether, ethylene, or gas or vapors of equivalent hazard

Group D: Atmospheres such as acetone, alcohol, ammonia, benzene, benzol, butane, gasoline, hexane, lacquer solvent vapors, naphtha, natural gas, propane, or gas or vapors of equivalent hazard

CLASS II: Areas made hazardous by the presence of combustible dust

Group E: Atmospheres containing combustible

1. metal dusts, regardless of resistivity

2. dust of similarly hazardous characteristics having a resistivity less

than 100 k½-cm

3. electrically conductive dusts

Group F: Atmospheres containing combustible

1. carbon black, charcoal, or coke dusts having more than 8% total

volatile material

2. dusts so sensitized that they present an explosion hazard, and dusts

having a resistivity greater than 100 ½-cm but less than or equal to 1 x 108 ½-cm

Group G: Atmospheres containing combustible

1. dust having resistivity equal to or greater than 100 k½-cm 2. electrically nonconductive dusts

CLASS III: Areas made hazardous by the presence of easily ignitable fibers or dust, but which are not likely to be in suspension in the air in quantities that are sufficient to ignite

Division 1: Atmospheres where hazardous concentrations exist continuously, intermittently, or periodically under normal operating conditions

Division 2: Atmospheres where hazardous concentrations exist only in case of accidental rupture or breakdown of equipment Explosion-proof: Enclosures or housings are designed to withstand internal explosions and prevent the spread of fire to the outside.

Intrinsically-safe: Systems designed in which electrical energy in the circuits is not present at levels that would ignite a flammable mixture of a gas and air.

The IP Code Symbols

The chart at the right illustrates the use of special symbols in the IP classification system. In the "1st digit" column, not the grid-like symbols net to numbers 5 and 6. In the "2nd digit" column numbers 3-8 are symbolised by teardrop shaped symbols, sometimes enclosed in a box or a triangle, sometimes unenclosed (#7-8). These symbols can be placed on equipment to illustrate the IP protection provided.