IEC 60079-14 Explained: Design, Selection and Installation of Electrical Installations

Selecting certified explosion-protected equipment is only the first step toward achieving a safe hazardous area installation. Even properly certified equipment can become unsafe if it is installed incorrectly.

Incorrect cable glands, improper wiring methods, inadequate earthing, or the misuse of equipment in the wrong hazardous area can compromise the intended protection concept and create serious ignition hazards.

To address these risks, the explosion protection industry relies on IEC 60079-14 – Explosive Atmospheres – Part 14: Electrical Installations Design, Selection and Erection.

IEC 60079-14 is one of the most important standards within the entire IEC 60079 series because it establishes the requirements for selecting and installing electrical equipment in explosive atmospheres.

The standard provides practical guidance for engineers, designers, EPC contractors, installers, and commissioning personnel responsible for hazardous area electrical systems.

Because even the best Ex equipment can fail to provide adequate protection if installed incorrectly, understanding IEC 60079-14 is essential for anyone involved in hazardous area projects.

This article explains what IEC 60079-14 is, why it is important, and the major requirements that engineers and installers should understand.

Quick Answer

What Is IEC 60079-14?

IEC 60079-14 is the international standard that governs how electrical equipment should be selected and installed in hazardous areas.

The standard applies after hazardous area classification has been completed and after suitable explosion-protected equipment has been selected.

Its primary objective is to ensure that the explosion protection characteristics of certified equipment are maintained during installation and throughout its operational life.

The standard covers a broad range of topics, including:

• Selection of Ex equipment.
• Equipment Protection Levels (EPL).
• Wiring systems.
• Cable glands and cable entries.
• Earthing and bonding.
• Segregation requirements.
• Special requirements for different protection concepts.
• Documentation and installation verification.

Why Is IEC 60079-14 Important?

Many hazardous area incidents occur not because equipment is defective but because equipment has been installed incorrectly.

Examples of common installation problems include:

• Incorrect cable glands.
• Improper sealing arrangements.
• Damaged cable entries.
• Inadequate earthing and bonding.
• Incorrect equipment selection.
• Improper segregation of intrinsically safe circuits.
• Use of equipment in the wrong hazardous area.

IEC 60079-14 establishes practical requirements that help eliminate these errors and improve the overall safety of hazardous area installations.

Who Uses IEC 60079-14?

Although manufacturers frequently reference IEC 60079-14, the standard is primarily intended for personnel involved in the design and installation of hazardous area electrical systems.

Typical users include:

• Electrical design engineers.
• Instrumentation engineers.
• EPC contractors.
• Electrical installers.
• Commissioning engineers.
• Inspection personnel.
• Maintenance organizations.
• Facility owners and operators.

For many organizations, competency in IEC 60079-14 is considered a fundamental requirement for personnel involved in hazardous area electrical work.

When Does IEC 60079-14 Apply?

IEC 60079-14 is typically applied after hazardous area classification has been completed and before equipment is energized.

The hazardous area lifecycle can generally be summarized as follows:

1. Hazardous area classification.
2. Equipment selection.
3. Electrical installation.
4. Inspection and verification.
5. Operation and maintenance.
6. Repair and overhaul.

IEC 60079-14 primarily addresses the second and third stages of this lifecycle and provides the installation requirements that bridge equipment certification and long-term operation.

Scope of IEC 60079-14

IEC 60079-14 specifies the requirements for the design, selection, and installation of electrical equipment used in explosive atmospheres.

The standard applies to new installations, modifications to existing installations, and the extension of hazardous area electrical systems.

The requirements cover:

• Selection of explosion-protected equipment.
• Selection of wiring systems.
• Installation practices.
• Cable entries and cable glands.
• Earthing and bonding.
• Segregation of circuits.
• Special requirements for various protection concepts.
• Installation documentation and verification.

The standard applies to both gas and dust explosive atmospheres and is used extensively in the oil and gas, petrochemical, chemical, pharmaceutical, and power generation industries.

Major Requirements of IEC 60079-14

Although IEC 60079-14 contains extensive technical requirements, the major topics generally include:

• Equipment selection.
• Equipment Protection Levels (EPL).
• Wiring systems.
• Cable gland selection.
• Earthing and bonding.
• Segregation of intrinsically safe circuits.
• Inspection before commissioning.
• Competency requirements.

These requirements help ensure that explosion-protected equipment continues to provide the intended level of protection after installation.

Equipment Selection Requirements

One of the most important requirements of IEC 60079-14 is the proper selection of equipment for the intended hazardous area.

Equipment selection must consider:

• Hazardous area classification.
• Zone classification.
• Gas or dust group.
• Temperature class.
• Ambient temperature.
• Equipment Protection Level (EPL).
• Environmental conditions.

Improper equipment selection can result in equipment being installed in an area for which it is not suitable, significantly increasing the risk of ignition.

Equipment Protection Level (EPL) Requirements

IEC 60079-14 places considerable emphasis on Equipment Protection Levels because EPLs provide a direct link between hazardous area classification and equipment selection.

Zone	Minimum EPL
Zone 0	Ga
Zone 1	Gb
Zone 2	Gc
Zone 20	Da
Zone 21	Db
Zone 22	Dc

Correct EPL selection is one of the fundamental principles of hazardous area engineering and helps ensure that equipment provides an adequate level of protection for the area in which it is installed.

Wiring System Requirements

The installation of cables and wiring systems can significantly influence the integrity of explosion protection.

IEC 60079-14 establishes requirements related to:

• Cable types.
• Mechanical protection.
• Cable routing.
• Conduit systems.
• Protection against environmental damage.
• Protection against mechanical damage.

Improper wiring methods may compromise explosion protection and create safety hazards during the life of the installation.

Cable Gland and Cable Entry Requirements

Cable entries are among the most frequently identified deficiencies during hazardous area inspections.

IEC 60079-14 therefore establishes detailed requirements for:

• Selection of cable glands.
• Thread compatibility.
• Ingress protection.
• Sealing arrangements.
• Unused entry sealing.
• Mechanical retention of cables.

The cable gland itself forms part of the explosion protection system and therefore must be compatible with both the equipment and the intended hazardous area.

Earthing and Bonding Requirements

Proper earthing and bonding are essential to reduce the risk of dangerous potentials and electrostatic charge accumulation.

IEC 60079-14 establishes requirements for:

• Protective earthing.
• Bonding conductors.
• Continuity of grounding systems.
• Control of electrostatic hazards.
• Connection integrity.

Improper grounding arrangements can increase the risk of ignition and may also affect the performance of certain protection concepts such as intrinsic safety.

Requirements for Intrinsically Safe Circuits

IEC 60079-14 includes specific requirements for intrinsically safe installations because Ex i systems require additional measures to maintain their integrity.

Requirements may include:

• Segregation from non-intrinsically safe circuits.
• Proper cable identification.
• Earthing requirements for barriers.
• Verification of entity parameters.
• Protection against inadvertent interconnection.

These requirements help ensure that excessive energy cannot accidentally be introduced into intrinsically safe circuits.

Advantages of IEC 60079-14

IEC 60079-14 plays a critical role in hazardous area safety because it provides a consistent methodology for selecting and installing explosion-protected equipment.

By following the requirements of the standard, organizations can significantly reduce installation errors and improve the long-term reliability of electrical systems operating in explosive atmospheres.

Key advantages of IEC 60079-14 include:

• Provides a standardized approach to hazardous area installations.
• Reduces the likelihood of installation errors.
• Improves equipment reliability and operational safety.
• Promotes consistency between projects and facilities.
• Supports compliance with international standards and regulations.
• Facilitates inspection and maintenance activities.
• Helps preserve the integrity of explosion protection concepts.
• Improves communication between designers, installers, and inspectors.

For many organizations, compliance with IEC 60079-14 is considered an essential requirement for achieving a safe hazardous area electrical installation.

Limitations of IEC 60079-14

Although IEC 60079-14 provides comprehensive installation guidance, the standard should not be considered a substitute for engineering judgment and competency.

Some limitations include:

• Requires competent personnel for proper interpretation.
• Cannot replace detailed equipment manufacturer instructions.
• Does not eliminate the need for inspection and maintenance.
• Requires accurate hazardous area classification information.
• May require additional local regulatory requirements.

For these reasons, the standard should always be applied together with good engineering practices and proper personnel competency programs.

Special Installation Requirements for Different Protection Concepts

IEC 60079-14 recognizes that different protection concepts require different installation practices.

Examples include:

Protection Concept	Typical Installation Considerations
Ex d	Certified cable glands, flameproof joints, and sealing requirements.
Ex e	Terminal integrity, ingress protection, and conductor selection.
Ex i	Circuit segregation, entity parameter verification, and barrier installation.
Ex p	Protective gas systems, purge requirements, and monitoring systems.
Ex t	Dust ingress protection and surface temperature considerations.

Understanding these differences is essential because installation practices that are acceptable for one protection concept may be unacceptable for another.

Installation Verification Before Energization

Before a hazardous area installation is placed into service, IEC 60079-14 requires verification that the installation has been completed correctly.

Typical verification activities include:

• Confirmation of equipment suitability.
• Verification of equipment markings.
• Inspection of cable glands and cable entries.
• Verification of earthing and bonding.
• Inspection of wiring systems.
• Verification of intrinsically safe circuit segregation.
• Review of installation documentation.

This verification process helps identify installation deficiencies before the equipment is energized and significantly reduces the likelihood of future incidents.

Competency Requirements

One of the most important aspects of IEC 60079-14 is the recognition that hazardous area work should only be performed by competent personnel.

The standard emphasizes the importance of:

• Training.
• Knowledge of explosion protection principles.
• Understanding of hazardous area classification.
• Knowledge of Ex equipment markings.
• Practical installation experience.
• Ongoing competency assessment.

Many organizations use competency schemes and hazardous area training programs to demonstrate compliance with these requirements.

Common Installation Mistakes Identified by IEC 60079-14

Experience throughout the industry has shown that certain installation deficiencies occur repeatedly.

Common examples include:

• Incorrect cable gland selection.
• Missing stopping plugs.
• Improper thread engagement.
• Installation of equipment in the wrong zone.
• Damaged cable entries.
• Improper segregation of intrinsically safe circuits.
• Inadequate earthing and bonding.
• Failure to consider ambient temperature limitations.

Many of these deficiencies can significantly compromise explosion protection and may create serious ignition hazards.

Why Engineers Should Understand IEC 60079-14

Even engineers who do not directly perform electrical installations frequently rely on the requirements of IEC 60079-14 during design reviews, procurement activities, project execution, and troubleshooting.

A basic understanding of the standard helps engineers:

• Select suitable equipment.
• Review hazardous area designs.
• Identify non-compliant installations.
• Improve commissioning activities.
• Reduce installation errors.
• Improve long-term equipment reliability.
• Enhance hazardous area safety.

Because installation quality directly affects the integrity of every explosion protection concept, IEC 60079-14 remains one of the most important standards in the entire hazardous area lifecycle.

Frequently Asked Questions (FAQ)

What is IEC 60079-14?

IEC 60079-14 is the international standard that specifies the requirements for the design, selection, and installation of electrical equipment in explosive atmospheres. It provides guidance for ensuring that Ex equipment is installed correctly and safely.

Does IEC 60079-14 apply to all hazardous area installations?

Yes. The standard applies to electrical installations in both gas and dust explosive atmospheres and covers new installations, modifications, and extensions of existing systems.

Why is IEC 60079-14 important?

Even properly certified equipment can become unsafe if installed incorrectly. IEC 60079-14 helps prevent installation errors that could compromise explosion protection and create ignition hazards.

Does IEC 60079-14 cover inspection and maintenance?

No. Inspection and maintenance requirements are primarily covered by IEC 60079-17, while repair and overhaul requirements are covered by IEC 60079-19.

Does IEC 60079-14 include requirements for intrinsically safe systems?

Yes. The standard includes requirements for the installation and segregation of intrinsically safe circuits and references the need for proper entity parameter verification and system design.

Who should understand IEC 60079-14?

Electrical engineers, instrumentation engineers, EPC contractors, installers, inspectors, maintenance personnel, and facility operators should all understand the requirements of IEC 60079-14.

Conclusion

IEC 60079-14 is one of the most important standards in hazardous area engineering because it bridges the gap between equipment certification and safe operation in the field.

The standard establishes the requirements for selecting, installing, and verifying explosion-protected equipment so that the intended level of protection is maintained throughout the life of the installation.

Proper equipment selection, suitable cable glands, correct wiring methods, adequate earthing and bonding, and proper installation practices are all essential elements of a safe hazardous area electrical system.

Because many hazardous area incidents are caused by installation deficiencies rather than equipment failures, a solid understanding of IEC 60079-14 is essential for anyone involved in the design, construction, commissioning, and operation of electrical installations in explosive atmospheres.

Technical Review

References

• IEC 60079-14 – Explosive Atmospheres – Electrical Installations Design, Selection and Erection.
• IEC 60079-0 – Explosive Atmospheres – Equipment – General Requirements.
• IEC 60079-17 – Explosive Atmospheres – Electrical Installations Inspection and Maintenance.
• IEC 60079-19 – Explosive Atmospheres – Equipment Repair, Overhaul and Reclamation.
• IECEx System – International Certification System for Equipment Used in Explosive Atmospheres.
• International Electrotechnical Commission (IEC).
• EN IEC 60079-14 – Explosive Atmospheres – Electrical Installations Design, Selection and Erection.