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 CodeDescriptionSuitable for zones...
Ex iaIntrinsic safety 'ia'0, 1, 2
Ex ibIntrinsic safety 'ib'1,2
Ex icIntrinsic Safety 'ic'2
Ex dFlameproof protection1,2
Ex pPurge/pressurized protection1,2
Ex pxPurge/pressurized protection 'px'1,2
Ex pyPurge/pressurized protection 'py'1,2
Ex pzPurge/pressurized protection 'pz'2
Ex eIncreased safety1,2
Ex mEncapsulation1,2
Ex maEncapsulation0,1,2
Ex mbEncapsulation1.2
Ex oOil immersion1,2
Ex qSand / powder (quartz) filling1,2
Ex nType - n protection2
Ex sSpecial protectionNormally 1 and 2

Equipment complying with European (CENELEC) standards will bear the code EEx..

IP Rating

First Number MeaningSecond NumberMeaning
Refers to protection against solidsu00a0Refers to protection against liquidsu00a0
0No protection0No protection
1Protected against solid objects over 50mm (e.g. accidental touch by the hand)1Protected against water falling vertically
2Protected against solid objects over 12mm (e.g. accidental touch by the finger)2Protected against direct sprays from up to 15 degrees from vertical
3Protected against solid objects over 2.5mm (e.g tools, wires)3Protected against direct sprays up to 60 degrees from vertical
4Protected against solid objects over 1mm (e.g. small wires)4Protected against sprays from all directions. Limited ingress permitted.
5Protected against dust u0096 limited ingress (no harmful deposit)5Protected against low pressure jets of water from all directions. Limited ingress permitted.
6Totally protected against all dust6Protected against strong jets of water. Limited ingress permitted. E.g. acceptable for use on shipdecks.
7Protected against temporary affects of immersion between 15cm and 1m, for 30 minutes.
8Protected against long periods of immersion under pressure.

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