Facts and Conversions
| Guideline figures | Flammable atmosphere present | Standard | |||
| Continuously > 1000hrs/annum | Intermittently >10 < 1000hrs/annum | Abnormally < 10hrs/annum | |||
| IEC / Cenelec / Europe | Gas | Zone 0 | Zone 1 | Zone 2 | IEC 60079-10 |
| Dust | Zone 20 | Zone 21 | Zone 22 | IEC 61241-3 | |
| North America | NEC 505 Gas | Zone 0 | Zone 1 | Zone 2 | Listed in NEC 505-5 |
| NEC 500 Gas & dust | Division 1 | Division 2 | Listed in NEC 500-3(c) | ||
| Typical gas hazard | IEC 60079-0 Cenelec EN50014 | North AmericaNEC Article 500 (Class I)* | Minimum ignition energy (microjoules) |
| Acetylene | IIC | A | 20 |
| Hydrogen | IIC | B | 20 |
| Ethylene | IIB | C | 60 |
| Propane | IIA | D | 180 |
| Passive components |  |
|
| Well defined sources of stored energy considered in safety analysis |
 |
|
| Source of generated energy not more than * 1.5V, 100mA & 25mW |
 |
|
NOT |
Piezoelectric crystal protected components voltage or current enhancement |
 |
* Note: North America still uses 1.2V and 20 microjoules
 |
|
| Surface area | T4 Classification |
| < 20mm 2 | Surface temperature ? 275 °C |
| ? 20mm 2 < 10cm 2 | Surface temperature ? 200 °C |
| ? 20mm 2 | Power dissipation ? 1.3 W * |
* Reduced to 1.2W with 60°C ambient or 1.0W with 80°C ambient
| NEMA, UL & CSA type rating | Approximate IEC/IP classification | Abbreviated protection description |
| 1 | IP30 | Indoor, from contact with contents |
| 2 | IP31 | Indoor, limited, from dirt and water |
| 3 | IP64 | Outdoor, from rain, sleet, windblown dust and ice damage |
| 3R | IP32 | Outdoor, from rain, sleet and ice damage |
| 4 | IP66 | Indoor and outdoor, from windblown dust, rain splashing and hose directed water and ice damage |
| 4X | IP66 | Indoor and outdoor, from windblown dust, rain splashing and hose directed water and ice damage |
| 6 | IP67 | Indoor and outdoor, from hose directed water, water entry during submersion and ice damage |
| 12 | IP55 | Indoor, from dust , falling dirt and dripping non-corrosive liquids |
| 13 | IP65 | Indoor, from dust, spraying water, oil and non-corrosive liquids |
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* Located in non-hazardous area and maybe connected to hazardous area
** Hazardous area apparatus
(IEC/EN60529)
| First numeral Protection against solid bodies |
Second numeral Protection against liquid |
||
| No protection | 0 | 0 | No protection |
| Objects greater then 50mm | 1 | 1 | Vertically dripping water |
| Objects greater then 12mm | 2 | 2 | Angled dripping water -75° to 90° |
| Objects greater then 2.5mm | 3 | 3 | Sprayed water |
| Objects greater then 1.0mm | 4 | 4 | Splashed water |
| Dust protected | 5 | 5 | Water jets |
| Dust tight | 6 | 6 | Heavy seas |
| 7 | Effects of immersion | ||
| 8 | Indefinite immersion | ||
Example: IP65
equipment is dust-tight and protected against water jets