Why Standard Electrical Equipment fails in Hazards Zones?

Electrical equipment serves a significant function in 

• Industrial facilities, 
• Commercial installations, and 
• Public infrastructure. 

However, when normal electrical equipment is utilized in hazardous environments (where explosive atmospheres may exist due to flammable gasses, vapors, or dust), it can pose major ignition and explosion hazards.

Individual socket outlets can deliver electrical power from the grid at either 3 phase (415 V, 50 Hz) or single phase (240 V, 50 Hz). 

Office supplies are typically 240 volts, 50 Hz. 

Most electrical equipment operates at 240 V and 50 Hz.

The testing facility uses wide range of electrically driven equipment, including as computers, printers, and visual display devices. 

The work environment includes computers, fax machines, and photocopiers.

This post provides a complete risk assessment for the usage of common electrical equipment in such conditions, including potential dangers, root causes, & mitigation techniques.

Standard Electrical Equipment

Standard electrical equipment includes equipments that are not designed (or) certified for usage in explosive (or) flammable environments. 

This includes:

• Non-Ex certified motors
• General-purpose control panels.
• Standard light fittings
• Open-type Relays, Contactors, and Switches.
• Industrial power tools lack explosion-proof protection.

Hazardous Area Classification

Hazardous zones are defined by the frequency & duration of the existence of an explosive atmosphere:

Zone	Description	Example
Zone 0	Explosive atmosphere continuously	Inside fuel tanks
Zone 1	Likely in the normal operation	Refinery pump areas
Zone 2	Unlikely, but may occur occasionally	Storage areas with ventilation

Standard electrical equipment is unsuitable for Zones 0, 1, and 2.

Hazards

Electric shock occurs when an electrical current passes through the body, specifically the neurological system. 

The effect is determined by current strength, which is in turn determined by voltage and body resistance, 

i.e: Path length and skin surface resistance. 

Death can occur when the typical voltage of 240 V causes currents of more than 30 mA to pass via the body for more than 40 milliseconds. 

Minor shocks can also result in harm after an involuntary muscular contraction.

Burns from electrically hot surfaces or exposure to high currents.

Electrical sparks, short circuits, excessive heating, and aged wiring with flammable materials can produce explosions and fires.

Injuries caused by microwave and radio-frequency sources, as well as induction heating equipment.

Risks

Electrical equipment is commonly used outside of the testing facility, and users are generally familiar with safe use. 

As a result, the risk of damage is low, yet any injuries that happen may be minor or fatal.

Who is most probable to be Injured?

Electric shock is most likely caused by the user themself.

Fires and explosions can cause extensive injuries.

Control Measures

These safety measures are not intended to be extensive or to address issues of electrical equipment repair or construction, but rather to cover general testing & office use.

1). Plugs and Fuses

Avoid using cracked or broken plugs. The plugs must be properly wired, the wires securely fastened, and the cable held firmly by the strain relief grip.

The fuse rating must be appropriate for the appliance. 

Most electronic devices (computers, measuring instruments, etc.) requires only a 3 A fuse, which may load up to 720 W. 

For heavy equipment, reserve 13 A fuses (loading up to 3000 W). 

2). Cabling

Ensure cable is in good condition with no fractures in insulation. 

Cable must be strong enough to resist the wear & tear of testing (or) office use, as well as completely waterproof in areas where water may come into contact with the instrument.

Take extra precautions to prevent electrical cables from becoming twisted (or) severed by moving parts, especially if they move frequently. 

Ensure all cables are safely secured. Cables must not be routed over the floor in a way that creates a tripping hazard (or) exposes them to harm from passing traffic. 

Cable shields must be used when running cables across pathways.

3). Extensions/Adapters

It is acceptable to feed one four-way extension block from a single socket if it simply supplies low-power equipment (less than 500 W or 2 A). 

Extension leads cannot be daisy-chained. Kettles, microwaves, and heaters with significant power requirements cannot be operated on such an extension and must be powered by an installed plug point.

To quickly turn off electricity in an emergency, the location of the mains switch should be apparent and easily accessible.

Use

• Avoid using gear with exposed mains terminals.
• Avoid using ordinary electrical equipment near flammable or explosive gases. Ordinary electrical equipment can cause ignition.
• Avoid using ordinary electrical equipment in moist environments. Water could trigger a deadly short circuit.
• Wet equipment should never be used without testing. 
• Electrical equipment should only be “repaired” by a skilled individual.
• Before commencing, disconnect the equipment from the main power.

Standard Equipment Risks

Hazard	Root Cause	Risk Level
Arc Flash / Sparks	From contactors, switches (or) poor connections	High
Hot Surfaces	Motor casings, lamps (or) resistors	High
Static Discharge	Poor grounding & bonding	Medium
Overheating	Improper insulation (or) overloaded circuits	High
Ingress of Flammable Gas/Dust	Unsealed enclosures	High
Short Circuits	Exposed conductors (or) insulation breakdown	Medium

Testing

• Electrical equipment must be inspected periodically. 
• Equipment that failed a safety test should never be utilized.

Risk Remaining

If not handled properly, electric power will always pose a possibly fatal risk. Following the procedures outlined above, the risk should be minimized.

Matrix for Risk Assessment

Likelihood	Severity	Risk Level	Required Action
Likely	Major explosion	Extreme	Immediate removal of the equipment
Possible	Fire (or) flashover	High	Replace with certified Ex-equipment
Rare	Minor arc (or) trip	Medium	Monitor & plan safe replacement

Standards & Codes

• IEC 60079 Series: Explosive Atmospheres Equipment.
• NFPA 70 (NEC): Electrical installations in the hazardous places
• IS/IEC 60079: Indian adaptation for the explosive conditions.

Risk Mitigation Measures

• Replace ordinary equipment with zone-certified Ex-rated equipment (Ex d, Ex e, or Ex ia).
• IEC 60079-10-1 and 60079-10-2 specify proper zoning & hazardous area classification.
• Install explosion-proof enclosures when replacement is not an option.
• To prevent static discharge, ensure correct grounding and bonding.
• Routine inspection and maintenance in accordance with IEC 60079-17.
• Maintenance professionals receive training on safe practices & area classification.
• Purge and pressurization systems are used to control the internal environment in the enclosures.

Emergency Procedure

To ensure quick isolation, control, and mitigation of fire (or) explosion threats caused by the utilization of non-certified standard electrical equipment in hazardous (flammable/explosive) zones.

It is essential to switch off the power before any attempt is made to approach the individual who has been injured.

The technique is to be performed for emergency conditions like:

• Electrical spark (or) arc flash from the non-Ex rated equipment.
• Overheating in motors, lights, or contactors
• Short circuits within typical control panels
• Discharge causes the ignition of combustible gases, vapors, or particles.
• Equipment explosions (or) fire outbreaks.

Procedure for Emergency Response

Steps	Action
Step-1	Immediately turn off the power supply to the affected equipment (or) zone.
Step-2	Activate fire suppression systems, such as CO₂ or foam (if available).
Step-3	Raise the alarm and evacuate staff according to the site’s emergency protocol.
Step-4	Isolate the hazardous zone and secure it to prevent illegal entry.
Step-5	Inform the Fire Safety and Electrical Teams immediately for assessment.
Step-6	Check for the secondary hazards: Gas leaks, residual heat, and falling debris.
Step-7	Use inherently safe equipment throughout the emergency response.
Step-8	Report the incident to the safety officer and commence a root cause investigation.
Step-9	Implement lockout/tagout (LOTO) on failed equipment.
Step-10	Document the event for the future corrective actions and hazard prevention.

Required Emergency Equipment

• Portable Fire Extinguishers (CO₂ & Dry Powder)
• Explosion-resistant lighting and radios
• Gas detectors (methane, propane, hydrogen sulfide, etc.)
• PPE includes flame-resistant clothes, helmets, gloves, and boots.
• Emergency shutdown buttons (or) remote ESD panels
• First aid kits include burn & smoke inhalation care.

Post-Emergency Actions

• Conduct incident investigation using IEC 60079 recommendations.
• Examine all electrical equipment utilized in dangerous environments.
• Replace non-compliant equipment with approved Ex-rated models.
• Review the Hazardous Area Classification (HAC).
• Educate employees on risk detection and equipment handling.
• Update the Risk Assessment & Emergency Response Plan.

Conclusion

The use of standard electrical equipment in potentially dangerous circumstances exposes individuals to risks that cannot be unacceptable.

Even a minor arc or spark can cause catastrophic explosions, leading to loss of life, property damage & regulatory violations.

An appropriate risk assessment must always result in:

• Replace with certified explosion-proof equipment.
• Consistent conformance with international norms
• Effective maintenance and worker training.
• Always prioritize safety over money or convenience.