Informative Annex 9



Informative Annex 10 A

IP & NEMA Ratings & Enclosures

These Informative Annexes are for the use of the Task Force and are not to be included in the API Standards

Annex 10A contains the following:

1) Frequently asked questions concerning NEMA Enclosure……………….Pg 1

2) Explanation of the IP and NEMA protection Codes……………………...Pg 2

Annex 10B contains the following:

1) NEMA Standards publication: A brief comparison between NEMA

250 Enclosures and IEC 60529 - IP designated enclosures……………….Pg 1

| |Frequently Asked Questions Concerning NEMA Enclosures |

| | |

|1. |The NEMA 4 enclosure appears to be a dust proof enclosure, and not explosion proof. What enclosure should be used in a pit |

| |containing explosive methane gas? |

| | |

| |Type 4 is not an explosion proof enclosure. Look at Type 7, Class I, Group D (for methane gas), or a combination of Type 4 and 7 |

| |which is readily available from manufacturers. Table SA-1 in the standard shows the combinations. NFPA 497M, Classification of |

| |Gases in Hazardous Locations, and Article 500 of the National Electrical Code, which are referenced in the NEMA Standard, provide |

| |further information on these types of applications. |

| | |

|2. |Do you have any standard for distribution transformer tanks? |

| | |

| |These are referred to as the "enclosures" and are contained in the ANSI C57.12.20-series standards which can be purchased from |

| |Global Engineering. |

| | |

|3. |What NEMA enclosure rating meets/exceeds IP 65? |

| | |

| |It is not possible to state that an IP rating is equivalent to a NEMA Type designation. An IP rating only considers protection |

| |against ingress of solid foreign objects and ingress of water. The NEMA Types consider these but also consider other items such as|

| |corrosions and construction details. For this reason it is possible to say that a NEMA Type is equivalent to an IP rating but it |

| |is not possible to state that an IP rating is equivalent to a NEMA Type. To the question of IP 65 if you refer to the information |

| |on the NEMA web site you should see that a Type 6 and a Type 6P meet or exceed an IP 67. They would therefore meet an IP 65. |

| |After some recent studies the comparison chart will be redone in the future and will indicate a Type 4 and a Type 4X is equivalent |

| |to an IP 66 and the Type 6P is being changed to an IP 68. All other Types are below an IP 65. |

| | |

|4. |What does this mean: "Requirements: US or Japan 100-240 vac 50- 60 Hz power supply with US connector - NEMA 10"? |

| | |

| |NEMA 10 is a standard enclosure type. Type 10 - Enclosures are constructed to meet the requirements of the Mine Safety and Health |

| |Administration, 30 CFR, Part 18. |

| | |

|5. |What is the proper NEMA standard to specify dustproof requirements for the controller, motor, and other accessory apparatus? |

| | |

| |NEMA 250-1997, "Enclosures for Electrical Equipment (1000 Volts Maximum)."  This document can be purchased from Global by clicking |

| |here or by calling 800.854.7179. |

| | |

|6. |Does an enclosure have to be submitted to NEMA for approval? |

| | |

| |NEMA does no testing nor certification. To claim compliance with the requirements for a specific NEMA enclosure type, a |

| |manufacturer would have to comply with the requirements contained in NEMA 250-1997, "Enclosures for Electrical Equipment (1000 |

| |Volts Maximum)."  This document can be purchased from Global by clicking here or by calling |

| |800.854.7179. |

| | |

|7. |Where can I find construction requirements for NEMA enclosures? |

| | |

| |NEMA standards tend to be written as performance standards. NEMA standard publications 250-1997 and ICS 6 have some information |

| |concerning construction, such as wire bending space, etc. |

| | |

2) The following is an explanation of the IP and NEMA protection Codes

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The protection of enclosures against ingress of dirt or against the ingress of water is defined in IEC529 (BSEN60529:1991). Conversely, an enclosure which protects equipment against ingress of particles will also protect a person from potential hazards within that enclosure, and this degree of protection is also defined as a standard.

The degrees of protection are most commonly expressed as "IP" followed by two numbers, e.g. IP65, where the numbers define the degree of protection. The first digit (Foreign Bodies Protection)shows the extent to which the equipment is protected against particles, or to which persons are protected from enclosed hazards. The second digit (Water Protection) indicates the extent of protection against water. The wording in the table is not exactly as used in the standards document, but the dimensions are accurate.

The first digit in the rating is the protection against contact and foreign bodies. The second digit in the rating is the water protection factor. The third digit in the impact protection factor  It is normally displayed in the format below.

IP s l (i)

s = solids, l=liquids and i= impact (optional)

|First Index - Foreign Bodies Protection, Solids |

|Index |Protection against Human/Tool Contact |Protection against solid objects (foreign bodies) |

|0 |No special protection |

|1 |Back of hand, Fist |Large foreign bodies, diam. >50mm |

|2 |Finger |Medium-sized foreign bodies, diam. >12 |

|3 |Tools and wires etc with a thickness >2.5mm |Small foreign bodies, diam. >2.5mm |

|4 |Tools and wires etc with a thickness >1mm |Granular foreign bodies, diam. >1mm |

|5 |Complete protection, (limited ingress |Dust protected; dust deposits are permitted, but their volume must not affect the |

| |permitted) |function of the unit. |

|6 |Complete protection |Dust-proof |

 

|Second Index - Water Protection, Liquids |

|Index |Protection against water |Protection from condition |

|0 |No special protection |

|1 |Water dripping/falling vertically |Condensation/Light rain |

|2 |Water sprayed at an angle (up to 15º degrees from the vertical) |Light rain with wind |

|3 |Spray water (any direction up to 60º degrees from the vertical) |Heavy rainstorm |

|4 |Spray water from all directions, (limited ingress permitted) |Splashing |

|5 |Low pressure water jets from all directions, (limited ingress permitted) |Hose down, residential |

|6 |High pressure jets from all directions, (limited ingress permitted) |Hose down, commercial. |

| | |eg. Ship decks |

|7 |Temporary immersion, 15 cm to 1m |Immersion in tank |

|8 |Permanent Immersion, under pressure |For use on Titanic recovery vehicle |

   

|Third Index - Impact Protection, Impact |

|Index |Protection against impact |Equivalent mass impact |

|0 |No special protection |

|1 |Protected against 0.225J impact |eg. 150g weight falling from 15cm height |

|2 |Protected against 0.375J impact |eg. 250g weight falling from 15cm height |

|3 |Protected against 0.5J impact |eg. 250g weight falling from 20cm height |

|4 |Protected against 2.0J impact |eg. 500g weight falling from 40cm height |

|5 |Protected against 6.0J impact |eg. 0.61183kg weight falling from 1m height |

|6 |Protected against 20.0J impact |eg. 2.0394kg weight falling from 1m height |

Examples:

 

|Umbrella- |IP-01 or IP-02 depending on umbrella |

|Chain link fence- |IP-10 |

|Chicken wire- |IP-20 |

|Screen- |IP-30 |

|Kevlar cloth- |IP-40 |

|Tent (camping)- |IP-42 |

|Saran wrap- |IP-51 |

|Bottle of wine- |IP-67 |

|Submarine- |IP-68 |

NEMA Ratings

There are many NEMA ratings available for enclosures.  Below, is an brief explanation of each NEMA rating.

NEMA 1 General Purpose - Indoors

Type 1 enclosures are intended for general purpose indoor use primarily to provide a degree of protection against contact with the enclosed equipment or locations where unusual service conditions do not exist.

NEMA 2 Drip Proof - Indoors

Type 2 enclosures are intended for general purpose indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt.

NEMA 3 Dust Tight, Rain Tight, & Ice/Sleet resistant - Indoors/Outdoors

Type 3 enclosures are intended for general purpose outdoor use primarily to provide a degree of protection against windblown dust, rain, and sleet; and to be undamaged by the formation of ice on the enclosure.

NEMA 3R Rain Proof & Ice/Sleet Proof - Indoors/Outdoors

Type 3R enclosures are intended for general purpose outdoor use primarily to provide a degree of protection against falling rain; and to be undamaged by the formation of ice on the enclosure.

NEMA 3S Dust Tight, Rain Tight, & Ice/Sleet Proof - Outdoors

Type 3S enclosures are intended for general purpose outdoor use primarily to provide a degree of protection against sleet; and to be undamaged by the formation of ice on the enclosure.

NEMA 4 Water Tight & Dust Tight - Indoors/Outdoors

Type 4 enclosures are intended for general purpose indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose directed water; and to be undamaged by the formation of ice on the enclosure.

NEMA 4x Water Tight, Dust Tight, & Corrosion Resistant - Indoors/Outdoors

Type 4X enclosures are intended for general purpose indoor and outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, and hose-directed water; and to be undamaged by the formation of ice on the enclosure.

NEMA 5 Superseded by NEMA 12 for Control Apparatus

Type 5 see NEMA 12

NEMA 6 Submersible, Water Tight, Dust Tight, & Ice/Sleet Resistant - Indoors/Outdoors

Type 6 enclosures are intended for general purpose indoor or outdoor use primarily to provide a degree of protection against the entry of water during temporary submersion at a limited depth; and to be undamaged by the formation of ice on the enclosure.

NEMA 7 Underwriters Lab Class 1-Groups C&D -Explosion Proof - Indoors

Type 7 enclosures are for indoor use in locations classified as Class I, Groups A, B, C, or D, as defined in the National Electrical Code.

Type 7 enclosures shall be capable of withstanding the pressures resulting from an internal explosion of specified gases, and contain such an explosion sufficiently that an explosive gas-air mixture existing in the atmosphere surrounding the enclosure will not be ignited.  Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting explosive gas-air mixtures in the surrounding atmosphere.   Enclosures shall meet explosion, hydro-static, and temperature design tests.

NEMA 8 Underwriters Lab Class 1-Groups C&D -Explosion Proof - Indoors

Type 8 is same as NEMA 7, except the unit is oil-immersed

NEMA 9 Underwriters' Lab Class II - Groups E,F,G - Indoors

Type 9 enclosures are intended for special purpose indoor use in locations classified as hazardous (Class II, Groups E, F, or G, as defined in the National Electrical Code).

Type 9 enclosures shall be capable of preventing the entrance of dust.  Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting or discoloring dust on the enclosure or igniting dust-air mixtures in the surrounding atmosphere.  Enclosures shall meet dust penetration and temperature design tests, and aging of gaskets (if used).

NEMA 10 Bureau of Mines

NEMA 11 Corrosion Resistant & Drip Proof - Oil Immersed - indoors

NEMA 12 Industrial Use - Dust Tight & Drip Tight - Indoors

Type 12 enclosures are intended for industrial indoor use primarily to provide a degree of protection against dust, falling dirt, and dripping noncorrosive liquids.

NEMA 13 Oil Tight & Dust Tight - Indoors

Type 13 enclosures are intended for industrial indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and noncorrosive coolant.  

Comparing NEMA and IP enclosure ratings. 

This comparison is only approximate, and it is the responsibility of the user to verify the enclosure rating necessary for the given application.  

 

Enclosure type | IP23  | IP30  | IP32  | IP55  | IP64  | IP65  | IP66  | IP67  | |1 |[pic] |  |  |  |  |  |  |  | |2 |  |[pic] |  |  |  |  |  |  | |3 |  |  |  |  |[pic] |  |  |  | |4 |  |  |  |  |  |  |[pic] |  | |4X |  |  |  |  |  |  |[pic] |  | |6 |  |  |  |  |  |  |  |[pic] | |12 |  |  |  |[pic] |  |[pic] |  |  | |13 |  |  |  |  |  |[pic] |  |  | |[pic]

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