Basic protection by MEANS OF an enclosure

The protection that an enclosure can provide by encasing hazardous or sensitive parts is identified in accordance with IEC 60529 by means of a combination of numbers and letters.

THE CODE DEFINES STANDARDISED PROTECTION LEVELS AGAINST

•  direct contact with dangerous electrical or mechanical parts (basic protection)
  
•  penetration by foreign matter into the protected area
  
•  penetration by moisture or water into the protected area

and is specified as a protection rating by means of the IP code (International Protection).

pROTECTION AGAINST CONTACT AND FOREIGN MATTER

PROTECTION AGAINST WATER | EXTENDED PROPERTIES

If the protection rating is specified by means of the code numbers (e.g. IP 54), the first digit applies to both the foreign matter protection and also protection against contact. If the protection rating is specified by means of the “additional letters” (e.g. IP 20C), the first code number applies only to the foreign matter protection, and the “additional letter” describes the contact protection.

A comparison of contact and penetration by solid foreign matter

A distinction is made between protection against direct contact and protection against penetration by foreign matter. In principle, both are specified simultaneously in the first numerical code.

In the second edition of IEC 60529 published in 2000, the difference between protection against direct contact (basic protection) and protection against penetration by solid matter was addressed for the first time; in principle both of these defined simultaneously by the first code number.

HIGHER PROTECTION FACTOR FOR SAFE OPERATION

In some cases, however, the protection against direct contact is more important, and the level of protection to be chosen is higher than the protection against penetration by solid foreign matter. This often results in misunderstandings in the specification. in accordance with IEC 61439, general protection against direct contact in switchgear assemblies, for example, does not have to be IP 20 but only IP XXB. If IP 20 is required for other reasons, then IP XXB is automatically covered as well.

PROTECTION CLASSES AND TEST METHODS

The distinction is critical in the realisation of higher protection ratings (e.g. IP 4X), which is best clarified using the description of the test methodology:

•  Protection against direct contact is determined with a test probe. The test is considered to have been passed if the access probe penetrates into the protected area up to a defined length (for IP and IP XXC XXD, this is the entire length of 100 mm up to the stop), but cannot touch any dangerous parts in the process.
•  Protection against penetration by solid matter is determined with the aid of a rigid test wire, whereby the full diameter of this wire (IP 3X = 2.5 mm, IP 4X = 1 mm) must not penetrate through openings into the protected area. In addition, this wire must represent a moveable, round object. This means that a labyrinth can indeed prevent the wire from penetrating, however it must be ensured based on a cross-sectional drawing or by means of other methods that a ball with the same diameter also cannot fully penetrate into the enclosure. This is not the case with many labyrinths.

“REAL” IP 4X INSTEAD OF ONLY IP 3XD

This fact means that some enclosures that were originally designed as IP 4X only comply with IP 3XD or less by today’s evaluation benchmarks. In most cases, this is also sufficient for an outdoor installation. However, for some applications (e.g. in the construction site environment) a “real” IP 4X is required.

CABINET AND ENCLOSURE SYSTEMS CERTIFIED BY ÖVE

All of our enclosure series were tested in accordance with current criteria (60529 ÖVE / ÖNORM EN: 2014) and certified by the Austrian Electrotechnical Association (ÖVE). Our polyester enclosures (cabinets and pillars) comply with protection rating IP 44 when assembled. On request, they can also be designed to be protected against dust (IP 54).

In some cases it may be necessary also to implement a protection rating that is lower than IP 44 due to certain operating conditions such as, for example, increased dissipated heat inside the enclosure. This could be done, for example, by the subsequent installation of ventilation grilles of a lower protection rating. Our TECHNICAL SALES department would be happy to advise you on these topics.

In some switchgear assemblies, a defined minimum protection rating must also be maintained even after opening the enclosure. For distributors complying with IEC 61439-3, this is IP 2XC when there is provision for operation by electrical laypersons (installation distributors, metering distributors). To be generally considered as basic protection in accordance with IEC 60364, an enclosure or contact protection cover must comply with at least IP XXB.

However, the specification “XX” is not suitable to represent the actual protection rating of the product. The protection rating is measurable; hence the “X” is an inadequate specification. If no protection against penetration by water is required or realised when the case is opened, then the correct specification is IP 20C. Likewise, the “X” is not regarded as a product specification for protection ratings of the outsides of enclosures. Here, the specification can be IP 44 or IP 54, for example, but cannot be IP 4X or IP X4.