How Poor Cable Selection Causes EV Charging Fires

Electric vehicles are booming in India, but so are reports of charging fires and short circuits. Recent incidents include an electric scooter that exploded while charging in Agra (September 2025) after a short circuit in its wiring, and multiple fires in Gujarat, from buses at depots to scooters in apartment parking lots.

This blog examines EV charging fire risks in India through three critical areas:

• Why charging fires are often cable failures, not battery faults
• How poor cable selection, installation, and accessories create overheating and fire risk
• What standards, certifications, and best practices are essential for safe EV charging

Why Do EV Charging Fires Often Start in Cables and Wiring?

Analysts note that as India’s public chargers have grown fivefold, safety concerns have risen. Fires in Gujarat (2024) included a BRTS bus charging fire and a tragic battery explosion in Surat. These cases highlight that charging fires are often electrical problems, frequently in the cables and wiring rather than mysterious battery malfunctions.

Cables carry high current from the grid to chargers and into the vehicle batteries. AC charging cables handle 230–415V at up to 32A, while DC fast-charging cables carry hundreds of volts at well over 100A.

If cables are undersized or poor quality, they overheat. Just as a narrow hose cannot carry the flow of a firehose, thin cables heat under heavy current. Cheap, uncertified cables often use thinner copper or even aluminum conductors with flimsy insulation, making them unsafe for continuous EV charging. Aluminum cables, in particular, heat more and carry less current, making them unsuitable for continuous heavy loads. By contrast, high-quality copper cables offer far lower resistance and heat generation.

Cable thicknessmust match current. For example, home EV chargers (Level 2, 3.3–7.2kW) draw 15–32A. Industry guides recommend at least 4 sqmm copper cable for a 16 A charger and 6 to 10 sqmm for a 32A charger.

Why Undersized EV Charging Cables Are Dangerous

Too-thin wires heat up under load, risking melted insulation and fire. Voltage drop in long or thin cables slows charging and increases heat. Correctly sized, single-core copper cables avoid excess heat buildup. Experts emphasize dedicated circuit with proper gauge copper cable, MCBs and RCDs as mandatory for safe charging.

India’s climate magnifies risks. High ambient heat and humidity strain charging systems. Hot summer temperatures and direct sunlight can raise cable and charger temperatures well beyond the normal operating range. Cables under constant sun or in unventilated basements lose insulation quality faster. Voltage spikes or brownouts can cause arcing, further heating.

Human factors also play a role. Improper installation is another hazard. Loose screw terminals, poor crimps, or exposed conductors create high-resistance hot spots that can quickly ignite. Even good cables fail if poorly connected. DIY setups, tapping chargers into lighting circuits, or using extension cords are recipes for overload and overheating.

Low-cost accessories worsen the risks. Many generic charging cables and adapters lack surge protection, earth continuity, or thermal sensors. Experts advise using certified chargers with proper earthing, RCDs, and surge protection instead of improvised wiring.

Common EV Charging Installation Mistakes That Causes Fires

In apartments, Resident Welfare Associations (RWAs) often rush installations without upgrading building infrastructure. If multiple EVs draw high current without DISCOM-approved load increases, old wiring and meters overload. DIY electricians may use aluminum feeders, skip RCCBs, or fail to ground chargers. One case involved upgrading from 10 sqmm to 16 sqmm loops after a fire scare, which could have been avoided with proper design from the start.

Even professional installations can fail if not inspected. For example, burnt connectors, mismatched ferrules, or exposed wires have caused fires. Experts recommend electrical inspections before adding chargers, dedicated circuits with 30 mA RCDs, and proper conduit routing. Public charging operators (CPOs) face stricter requirements: temperature monitoring, fire, and regular maintenance. Inspections catch frayed cables or loose lugs before they cause fires. In humid depots, cleaning contracts and testing protective devices is vital.

EV Charging Safety Standards: The Role of BIS, AIS, and Certification

India mandates Bureau of Indian Standards (BIS) EVSE standards (IS 17017 series), harmonized with IEC norms. These cover cable fire resistance to connector safety, IP55/IP65 enclosures, RCDs, and surge arrestors. Certified cables are flame-retardant (FR-LSH rated), tested for heat endurance, insulation stability, and durability, and carry ISI marks. Compliance reduces risks of insulation breakdown and overheating.

ARAI/ICAT certification (AIS-138) adds tests for temperature, water/dust ingress, and shock. In sum, buying only BIS/ARAI-certified chargers and cables is non-negotiable. Uncertified equipment may save costs but can fail catastrophically.

Choosing Safe Cables: Tips for EV Owners and Installers

Here are key tips to avoid the cable trap:

• Always use copper, correctly gauged cable: For a 15–16 A charger (~3.3 kW), use ≥4 sqmm copper; for a 30–32 A charger (~7.2 kW), use ≥6 sqmm. If the cable run is long (over 10–20 m), bump up a size (e.g., 10 sqmm) to prevent voltage drop. Crucially, the cable must be the right type – single-core, flame-retardant insulation (FR or FR-LSH), not a generic multitask wire.
• Inspect and replace damaged cables: Look for fraying, cracks, burn marks, or loose pins. Even small cuts in the sheath can expose conductors and spark. In apartment or depot settings, managers should schedule formal inspections of all chargers and wiring every few months.
• Install dedicated protection: Put the EV charger on its own MCB or circuit breaker (typically 32 A for home chargers) and a 30 mA RCCB. This isolates the charger from other loads. Never plug an EV charger into a multi-socket extension cord or a general outlet. Use conduits or cable trays to shield the cable from physical damage.
• Ensure proper grounding and surge arrestors: Good earthing (ground connection) is vital. All charge points should have an earth rod or building ground with a low-resistance path. Install surge protectors to divert spikes (from lightning or grid surges) away from the charger and cable.
• Watch the environment: Charge in shaded, ventilated areas whenever possible. Avoid placing chargers (and their cables) under direct sun or next to heat sources. In humid or dusty sites, keep cables off the ground and out of puddles. Never charge near flammable gas cylinders or solvents, a worst-case fire could spread quickly in such clutter.
• Use certified products: Buy cables and chargers that explicitly carry ISI/BIS or ARAI marks. If a vendor can’t show compliance, walk away. Even if an uncertified cord looks robust, it may be made of sub-par copper alloy or poor PVC. For peace of mind, stick with reputable brands or OEM-supplied cables; many EV makers now bundle ISI-rated cords with their cars.
• Schedule maintenance and monitoring: Fleet operators and CPOs implement a routine checklist. Include thermal imaging or temperature sensors on cable runs if possible. Many modern chargers can auto-shutdown at high temperature. If using multiple chargers in one parking, stagger charging times to avoid tripping the main feeder. Document any wiring changes and keep a log for insurance audits.
• Confirm certifications: Ensure that the installation and equipment have all required approvals. For home users, ensure the electrician tests the earth and obtains any needed electrical clearance. CPOs should register their hardware under BIS’s Compulsory Registration Scheme (CRS) and display the certificate. Consider getting an inspection by a licensed electrical safety auditor, especially for large or public charging setups.

Checklist: How to Avoid Cable-Related Fire Risks

• Use copper cables (not aluminum) for adequate cross-section for your charger’s current.
• Check for ISI/BIS certification marks.
• Have a qualified electrician install the cable on a dedicated circuit with its own MCB and RCCB. Follow conduit and grounding requirements.
• Inspect regularly for signs of wear (cuts, melting, discoloration) and tight connections.
• Avoid cheap adapters or uncertified plugs. Use only chargers and cables designed for EV use.
• Keep cables clear of heat and moisture; provide ventilation around chargers. Install weatherproof enclosures.
• Ensure your building’s electrical panel can handle the added load. Apply for a DISCOM load enhancement if needed.
• Install surge protection as per standards to protect against grid spikes.
• Train staff and tenants on EV safety rules and that it’s a shared responsibility.
• Keep all test reports (BIS, ARAI, CEIG) updated. Inform your insurer about the charging setup to keep coverage valid.

By adhering to these guidelines, EV owners and operators can ensure that hot wires stay cool. In India’s climate and busy buildings, neglecting cable quality invites disaster. But with proper cable selection, installation, and upkeep, all backed by official standards, EV charging can be both green and safe. Stakeholders from RWAs to CPOs and electricians must stay vigilant: the cables that power our EV revolution should never become the spark that ends it.