Which `type of protection´ [electrical equipment safety]

When electrical equipment has to be installed in a hazardous area it must be prevented from igniting the flammable gas with which it may be in contact. There are currently seven internationally agreed `Types of Protection´ available to the manufacturer or user for this purpose together with several other methods not necessarily acceptable outside the country of certification. The author examines the applications and limitations of each protection type which should enable the user to eliminate the unsuitable types of protection. Each type of protection has its limitations (e.g. electrical, physical or financial) and some research is usually necessary before an optimal system is arrived at