Don’t Ever Compromise on Power Supplies for ATEX Systems
“It’s more than just a logo on a datasheet” – says Marco van der Linden, UK Country Manager for PULS Power
DIN Rail Power supplies are found in almost every industrial process control system. They may be required to provide power to electronic controls, relays and contactors, for PoE communication systems or for motor drives. During the conversion from AC mains to lower DC power outputs, switch mode power supplies produce high voltages and currents that, if incorrectly designed, may cause sparks and may also generate excess heat through inefficient design topologies being used.
Certification of equipment and protective systems for use in hazardous areas such as offshore installations have been in force for many years and there is a well-established supply chain for electrical equipment designed to meet the regulatory requirements.
Preventing the creation of explosive atmospheres and eliminating sources of ignition are the two main ways of reducing risk. Ensuring the correct equipment is installed in the system can help greatly in this. In addition, there is a duty placed on employers (The Dangerous Substances and Explosive Atmospheres Regulations 2002) to eliminate or control the risks from explosive atmospheres in the workplace.
Introduced in 2003, the ATEX Directive covers both electrical and mechanical equipment and is mandatory for any equipment to be used in hazardous areas throughout the EU. Electrical equipment requires independent certification for use in a Zone 1 area and most electrical equipment manufacturers also provide additional certification for Zone 2 products.
IECEx is a further worldwide certification system for electrical products and requires full compliance to IEC International standards. Equipment manufacturers must have been awarded an IECEx Certificate of Conformity by an approved IECEx Notified Body. It covers the manufacturing facility and its quality assurance processes in addition to approval of the end product.
Products from reputable manufacturers would be expected to supply products certified to both schemes.
How Does ATEX Apply to Power Supplies?
To meet ATEX regulations, power supplies must be designed with larger creepage and clearance distances on the PCB than may be normal, this provides “over surface” and” through air” protection against conduction or sparks. Outputs must be protected from overload and overcurrent to prevent the possibility of damage to the end system causing temperature increases or fire. Internal components should be placed to ensure cool running and reduce internal self-heating. Conformal coating may be required on the PCB not only to protect against application atmosphere but also increase resistance to shock and vibration.
PULS Power are the only company worldwide focused entirely on the development and production of DIN rail power supplies. For almost 40 years they have been setting the standards in terms of efficiency and quality for industrial power conversion products. PULS manufactures a wide range of ATEX approved power supplies and accessories which are tested according to EN 60079-0 and EN 60079-15 and comply with the ATEX Directive (Class I Div 2, IECEx, ATEX). These devices may be used in systems in potentially explosive atmospheres of zone 2, category 3G.