Buying Guide on Explosion-proof Local Control Stations

A local control station (LCS) is an integral part of industrial control systems that allows operators to manage and control equipment and processes in hazardous or explosive environments. When choosing an explosion-proof LCS, safety and compliance are paramount. In this buying guide, we'll explore key factors to consider when purchasing explosion-proof local control stations.

1. Understand Hazardous Area Classification 

Explosive or hazardous areas are classified based on the type and frequency of flammable materials present. The classification, typically done in accordance with standards like the National Electrical Code (NEC) or the International Electrotechnical Commission (IEC), determines the level of protection required for LCS. Identify the specific hazardous area classification where the LCS will be installed, whether it's a Class I, II, or III location, and Division/Zone classification.

2. Compliance with Safety Standards

Safety standards and certifications are crucial when selecting an explosion-proof LCS. Ensure that the LCS complies with relevant international standards such as:

UL (Underwriters Laboratories) 1203: A common standard for explosion-proof and dust-ignition-proof electrical equipment in North America.

ATEX Directive: Applicable in the European Union for equipment used in potentially explosive atmospheres.

IECEx: An international certification system for explosive atmospheres, recognized in multiple countries.

Check that the LCS is appropriately labeled with these certifications to guarantee it meets safety requirements.

3. Enclosure Type and Material

The enclosure of an explosion-proof LCS must be robust and durable. Consider the following:

Material: Enclosures are typically constructed from materials such as aluminum or stainless steel, which are corrosion-resistant and suitable for harsh environments.

Type: The LCS should have an enclosure that meets the required protection level. Common types include NEMA 7 for Class I, Division 1 areas and NEMA 4X for Class I, Division 2 areas.

Gasket Seals: Ensure that the LCS has effective gasket seals to maintain the integrity of the enclosure, protecting it from the entry of hazardous materials.

4. Operating Temperature and Environmental Conditions 

The LCS must withstand the environmental conditions of the hazardous area. Factors to consider include:

Operating Temperature: Ensure the LCS is rated for the expected temperature range within the hazardous area. Some environments may require heaters or coolers to maintain the proper temperature.

Dust and Moisture Resistance: If the area is prone to dust or moisture, the LCS should have appropriate protection.

Impact Resistance: In areas with potential for impact, look for an LCS with the necessary impact protection ratings.

5. Component Configuration and Customization 

LCS units often have various components, such as switches, indicators, and terminals. Depending on the specific control needs of your application, consider:

Component Types: Choose components like push buttons, pilot lights, motor starters, or selector switches that match the control requirements.

Customization: Some LCS providers offer customization options to tailor the component configuration to your needs.

Spare Capacity: Ensure there is spare capacity for future expansion or additional controls.

6. Cable Entry and Conduit Options 

Cable entry and conduit options play a significant role in maintaining the integrity of the enclosure. Evaluate:

Cable Entry Types: The LCS should provide multiple cable entry options, including threaded hubs or conduit openings, to accommodate different conduit sizes and cable types.

Conduit Sealings: Verify that the conduit sealings are included and suitable for the hazardous area classification.

Conduit and Cable Clamping: Look for options to securely clamp and strain relieve conduits and cables to prevent damage and maintain safety.

7. Ease of Installation and Maintenance 

Consider the ease of installation and maintenance for the LCS:

Mounting Options: LCS units can be wall-mounted, floor-mounted, or integrated into control panels, so choose the installation method that suits your setup.

Accessibility: Ensure that the LCS provides easy access for maintenance without compromising safety.

Labeling: Clear and durable labeling of components and wiring simplifies both installation and maintenance.

8. Local Regulations and Inspections 

Local regulations may impact the use of explosion-proof LCS. Be aware of any specific requirements and ensure that the LCS complies with them. Periodic inspections by certified personnel may also be mandatory for safety and compliance.

9. Price and Warranty 

While cost is a factor, prioritize safety and compliance over price. High-quality, certified LCS units may come at a higher initial cost but offer long-term safety and reliability. Additionally, check the warranty offered by the manufacturer, as it can provide added assurance of the product's durability and performance.

10. Technical Support and Service 

Choose a reputable manufacturer or supplier with a history of providing quality products and good customer service. Knowledgeable technical support and readily available service and replacement parts can be crucial for maintaining your explosion-proof LCS.

In conclusion, selecting an explosion-proof local control station involves understanding hazardous area classifications, ensuring compliance with safety standards, considering enclosure materials and protection levels, assessing environmental conditions, customizing component configuration, evaluating cable entry options, ease of installation and maintenance, adhering to local regulations, considering price and warranty, and choosing a supplier with reliable technical support and service. By taking these factors into account, you can confidently select the right LCS for your hazardous area control needs.