Ex Components

What is an Ex Component ?

Definition : An Ex component is a 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.

Examples:

An Empty Enclosure (More on this in Explosion proof or Flameproof + Documentations & certifications )
Components or assemblies of components for use with equipment which complies with the requirements of one or more of the types of protection listed in IEC 60079-0

Definition as per IEC 60079-0

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

As Ex Components are not intended to be used alone and require additional consideration when incorporated into electrical equipment or systems, they do not have “Specific Conditions of Use” along with the associated “X” suffix for the certificate number.
Where this standard or one of its sub-parts specify “Specific Conditions of Use” and the associated “X” suffix for the certificate number, a “Schedule of Limitations” for the Ex Component certificate and the associated “U” suffix for the Ex Component certificate number shall be substituted for an Ex Component.

The symbol “U” refers to the SUFFIX U which is marked in the Certificate Number of the Ex Component . This component certificate with the “U” SUFFIX clearly shows that the reference component mentioned in the certificate is incomplete and requires further & addition considerations before putting it into an Ex equipment. This fact is elaborated in the “Schedule of Limitation “

Schedule of Limitation :- Additional document included in the certificate , detailing the additional evaluation required before putting the component into operation in a Ex Equipment.

Examples:

An empty Ex d Enclosure ( see Explosion proof or Flameproof if you are planning to design your own Ex d Control station or a Junction Box )
An Empty Ex e enclosure
Post Type Bushings
Conductor Bushings
Drain & Breather Valve for conduit installations

In contrast to the Component Certificate there is The Equipment Certificate.

Equipment certificates are for the complete assemblies