IP ratings are usually defined during the design stage of an installation but are often not fully understood in detail by specifiers and the resulting installation may not achieve the safety levels required. The IP ratings of cable glands in particular can lead to confusion about the level of protection that will actually be achieved in an installation.

For instance, the fitting of an IP66 cable gland to an IP66 enclosure can result in an installation with an IP rating of only IP54 because of issues with the sealing of the interface. Changes introduced in Edition 7 of IEC 60079-0 have addressed this issue of the IP rating of the interface between a cable gland and the equipment it is connected to, but in some cases the changes have been misinterpreted or overlooked during certification. 

The purpose of this paper is to explain in clear and simple terms what an IP rating means and more importantly what it does not mean (but is usually assumed to mean). The paper will discuss the changes to IEC 60079-0 with respect to IP ratings of cable glands and also a recent ExTAG Decision Sheet which clearly defines the intention of the changes. Some guidance will be given about what to look for to make sure that the installation meets its intended IP rating. Examples will be given of what can happen to an installation when IP ratings are not achieved, and the potential costs involved. The paper will also consider some practical solutions to the problems of water ingress into equipment where it is unavoidable.

Dr. Geof Mood

Dr. Geof Mood has been the Technical Director for CCG Cable Terminations for the last 5 years. He has specialised in the design, development and certification of cable glands and accessories for over 14 years but has also been involved in product development and certification of a variety of products such as heating, lighting and compressed air cylinders for many more years than he cares to admit to. Dr. Mood is an active member of a number of National and International standards committees which he attends as a cable gland expert.

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