"Increased safety" is a design technique where the equipment:

• does not produce any arcs or sparks in normal operation
• does not produce any high temperatures in normal operation
• has been been designed to guard against the possibility of arcs, sparks and high temperatures under specified abnormal conditions

This is typically accomplished by increasing the requirements for insulation, creepage/clearance distances, and security of connections beyond normal requirements. There may also be additional requirements for enclosures, terminals, and other parts relevant to ensuring that the equipment is (and remains) non-sparking.

Designs that don't respond to these design principles - such as complex semiconductor-based circuits - cannot normally be certified as increased safety and are specifically excluded from IEC 60079-7. Typical applications are therefore restricted to cables, terminal boxes, inductive windings and other relatively simple devices that can be made safe through the application of increased insulation requirements.

When successful, increased safety devices can be used in Zone 1 locations. Increased safety devices can therefore substititue for flameproof enclosures in similar hazardous areas. This makes it increasingly popular for items such as junction boxes because of the relatively easy design and test requirements.

Go to Protection Techniques.
Go to Certification Standards.
Go to Understanding ATEX.
Go to Understanding IEC 60079.