Technical Resources
We have gathered together a number of technical resources for use as reference on electrical projects.
DISCLAIMER: The information on this page and the PDF is for information only and R&M Electrical Group Ltd can not be held liable for any information therein.
Electrical Equipment Classification
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Electrical apparatus for use in hazardous areas needs to be designed and constructed in such a way that it will not provide a source of ignition. There are ten recognized types of protection for hazardous area electrical apparatus. Each type of protection achieves its safety from ignition in different ways and not all are equally safe. In addition to the equipment being suitable for the Gas Group and the Temperature Class required, the type of protection must be suitable for the zone in which it is to be installed. The different types of protection and the zones for which they are suitable are as follows:
| Equipment Code | Description | Suitable for zones... |
|---|---|---|
| Ex ia | Intrinsic safety 'ia' | 0, 1, 2 |
| Ex ib | Intrinsic safety 'ib' | 1,2 |
| Ex ic | Intrinsic Safety 'ic' | 2 |
| Ex d | Flameproof protection | 1,2 |
| Ex p | Purge/pressurized protection | 1,2 |
| Ex px | Purge/pressurized protection 'px' | 1,2 |
| Ex py | Purge/pressurized protection 'py' | 1,2 |
| Ex pz | Purge/pressurized protection 'pz' | 2 |
| Ex e | Increased safety | 1,2 |
| Ex m | Encapsulation | 1,2 |
| Ex ma | Encapsulation | 0,1,2 |
| Ex mb | Encapsulation | 1.2 |
| Ex o | Oil immersion | 1,2 |
| Ex q | Sand / powder (quartz) filling | 1,2 |
| Ex n | Type - n protection | 2 |
| Ex s | Special protection | Normally 1 and 2 |
Equipment complying with European (CENELEC) standards will bear the code EEx..
IP Rating
| First Number | Meaning | Second Number | Meaning |
|---|---|---|---|
| Refers to protection against solids | u00a0 | Refers to protection against liquids | u00a0 |
| 0 | No protection | 0 | No protection |
| 1 | Protected against solid objects over 50mm (e.g. accidental touch by the hand) | 1 | Protected against water falling vertically |
| 2 | Protected against solid objects over 12mm (e.g. accidental touch by the finger) | 2 | Protected against direct sprays from up to 15 degrees from vertical |
| 3 | Protected against solid objects over 2.5mm (e.g tools, wires) | 3 | Protected against direct sprays up to 60 degrees from vertical |
| 4 | Protected against solid objects over 1mm (e.g. small wires) | 4 | Protected against sprays from all directions. Limited ingress permitted. |
| 5 | Protected against dust u0096 limited ingress (no harmful deposit) | 5 | Protected against low pressure jets of water from all directions. Limited ingress permitted. |
| 6 | Totally protected against all dust | 6 | Protected against strong jets of water. Limited ingress permitted. E.g. acceptable for use on shipdecks. |
| 7 | Protected against temporary affects of immersion between 15cm and 1m, for 30 minutes. | ||
| 8 | Protected against long periods of immersion under pressure. |
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