Definition of a Component Enclosure

Published 16 Mar '20
Read Time: 5 mins

In terms of Hazardous Area Equipment, an Ex Component is defined differently from an Ex Equipment. From AS/NZS 60079.0 2012 Definitions, we have:

3.28
Ex Component
part of electrical equipment or a module, marked with the symbol “U”, which is not intended to be used alone and requires additional consideration when incorporated into electrical equipment or systems for use in explosive atmospheres

3.52
symbol “U”
symbol used to denote an Ex Component NOTE The symbol “U” is used to identify that the equipment is incomplete and is not suitable for installation without further evaluation.

Basically, a Component is a certified piece of Explosion Protected Electrical Equipment which cannot be used on its own but must be used in conjunction with other Ex Components and Ex Equipment to comprise an entire Equipment.

In a practical sense, these are certified enclosures which are EMPTY of components. In order to use a Component (“U” certified) enclosure with specific contents, there are several routes:

1. FITNESS FOR PURPOSE report must be compiled by a competent person, taking into account issues such as:

a. Internal heating and calculation of the worst-case surface temperature,
b. The certification of the assemblies to be installed in the Component Certified enclosure (if Ex e – this doesn’t matter if the enclosure is Ex d)
c. Clearance and creepage compliance and earth bonding compliance for Ex e
d.Investigations into the likelihood of pressure piling for Ex d enclosures.

2. UNIT VERIFICATION certificate can be applied for, if there is to be a limited production run of identically designed enclosure installations, (20 or more).

a. The Unit Verification (NOT Unit Certification – no such a thing) of the DESIGN is what occurs
b. This restricts the contents of the enclosures to exactly what is in the Unit Verification certificate.

Some Examples of Component Certifications:

Ex e Terminals Blocks                                                 (IECEx KEM 06.0014U)

Ex d/ tD Actuators                                                        (IECEx LCI 10.0022U)

Ex e Thermocouple Terminals                                   (IECEx SIR 05.0039U)

Ex d/ e/ tD Adaptors, Reducers and Plugs               (IECEx SIR 05.0042U)

Empty Ex d Enclosures                                                (IECEx FMG 06.0003U)

This material is produced by HAZ. The information is of a general nature only and should not be relied upon.  Each set of circumstances associated with compliance of hazardous areas and Type B compliance is unique and expert advice on your particular circumstances should be sought.  HAZ accepts no liability for any reliance on the information published on this website.