What Electrical Safety Means
Electrical safety encompasses the design, installation, maintenance, and operation of a building's electrical systems to prevent shock, electrocution, arc flash, and electrical fire. It covers everything from the utility incoming supply through switchgear, distribution boards, wiring, earthing/grounding, and end-use equipment.
Electrical faults are the leading cause of building fires worldwide. In Bangladesh, where electrical infrastructure quality varies significantly and informal wiring modifications are common, electrical safety is a critical risk area.
Applicable Standards & Codes
Electrical Standards in Bangladesh Context
- adopted BNBC 2020 Part 8 (Electrical) — Mandatory electrical installation provisions for all buildings in Bangladesh
- referenced IEC 60364 (Electrical Installations) — Primary international standard basis for BNBC electrical provisions
- differs BS 7671 (IET Wiring Regulations) — UK wiring standard; historically influential but not formally adopted
- referenced IEEE Standards (Power Systems) — Referenced for power distribution, earthing, and protection coordination
| Standard | Scope | Publisher |
|---|---|---|
| IEC 60364 | Low-voltage electrical installations — design, protection, wiring, earthing | IEC |
| BS 7671 (IET Wiring Regulations) | UK wiring standard — widely used in Bangladesh engineering practice | IET / BSI |
| NFPA 70 (NEC) | National Electrical Code — US standard for electrical installation | NFPA |
| NFPA 70E | Standard for Electrical Safety in the Workplace — arc flash, PPE, LOTO | NFPA |
| NFPA 110 | Standard for Emergency and Standby Power Systems (generators) | NFPA |
| BNBC 2020, Part 8 | Building electrical installations — Bangladesh requirements | HBRI / PWD |
| IEEE 399 / IEEE 1584 | Power system analysis / arc flash hazard calculations | IEEE |
Key Metrics & Acceptance Criteria
| Parameter | Standard / Source | Good Practice | Red Flag |
|---|---|---|---|
| Earthing/grounding resistance | IEC 60364 / BS 7671 | ≤ 5 Ω (general), ≤ 1 Ω (lightning protection, data centres) | > 10 Ω or untested |
| Insulation resistance | IEC 60364-6 / BS 7671 | ≥ 1 MΩ at test voltage (500V DC for 230V circuits) | < 0.5 MΩ or declining trend |
| RCD/RCCB trip time | IEC 60364 / BS 7671 | ≤ 300 ms at rated current, ≤ 40 ms at 5× rated | Not tripping or no RCDs installed |
| Circuit breaker rating vs. cable | IEC 60364 / BS 7671 | Breaker rating ≤ cable current-carrying capacity | Oversized breakers, rewired fuses, direct connections bypassing protection |
| Voltage at point of use | IEC 60038 / Bangladesh standard | 230V ± 10% (207–253V), 400V ± 10% 3-phase | < 200V or > 260V sustained |
| Power factor | Utility/BPDB requirements | ≥ 0.95 | < 0.85 (penalty charges, inefficiency) |
| Generator transfer time | NFPA 110 | ≤ 10 seconds (Type 10 — most commercial), ≤ 60 seconds (Type 60) | Manual transfer, no ATS, or ATS not tested |
| Generator fuel autonomy | NFPA 110 | ≥ 8 hours at full load for commercial buildings | < 4 hours or fuel supply unreliable |
| Thermographic survey | NFPA 70B / IEEE | Annual thermographic scan of switchgear, distribution boards | Never performed, hot spots > 40°C above ambient |
What to Inspect on Site
- Main switchgear room: Cleanliness, access clearance (≥ 900 mm front, ≥ 600 mm sides per NEC/BS 7671), labelling, signs of overheating (discolouration, burnt smell), arc flash warning labels.
- Distribution boards: All breakers labelled, no spare ways used without proper connection, panel covers in place, no exposed live conductors. Check for signs of heat (melted insulation, discoloured bus bars).
- Wiring: Look for surface wiring, spliced cables, daisy-chained extension leads, undersized cables feeding high loads (e.g., air conditioners on lamp circuit). In Bangladesh, informal wiring additions are extremely common.
- Earthing: Check the main earthing terminal, bonding connections to metalwork (water pipes, structural steel). Request earth resistance test records.
- RCDs/RCCBs: Press test buttons on all RCDs — they should trip immediately. Many buildings in Dhaka do not have RCDs on socket circuits.
- Generator room: Fuel storage compliance, exhaust routing, ventilation, ATS condition, battery condition, test log.
- Emergency lighting: Test function mode. Check battery backup duration (minimum 90 minutes per NFPA 101).
- Lightning protection: If installed, check conductor condition, connections, earth pits. Request test certificate (≤ 1 Ω earth resistance).
Bangladesh Electrical Context
- Grid reliability: Dhaka power supply has improved but outages remain common (2–4 hours/day in some areas). Generator backup is essential for commercial buildings.
- Supply voltage: Nominal 230V single-phase, 400V three-phase. Voltage fluctuation is common — stabilisers or AVRs are widely used.
- Utilities: DPDC (Dhaka city), DESCO (north Dhaka), BPDB (rest of country).
- Standards adoption: BS 7671 and IEC 60364 are the primary references for electrical design in Bangladesh. NEC is occasionally referenced. BNBC 2020 Part 8 covers basic requirements.
- Informal modifications: Electrical wiring modifications without professional design or installation are extremely common — extending circuits, adding loads without upgrading protection, using substandard cables. This is the primary electrical safety risk in existing buildings.
- Testing: Periodic electrical installation testing (every 5 years per BS 7671) is rarely done in Bangladesh. Request EICR (Electrical Installation Condition Report) or equivalent.
Gap Management
- Electrical survey — commission an EICR (Electrical Installation Condition Report) per BS 7671 Part 6 or equivalent. This is the baseline assessment that identifies all deficiencies.
- Priority remediation — address C1 (danger present) findings immediately. C2 (potentially dangerous) within 28 days. C3 (improvement recommended) within planned maintenance.
- Earthing upgrades — install RCDs on all socket circuits as a minimum. Test earthing resistance and improve to ≤ 5 Ω.
- Thermographic survey — annual thermal imaging of all switchgear and distribution boards. Cost-effective detection of hot joints, overloaded circuits, and failing connections before they cause fires.
- Generator compliance — ensure ATS is functional and tested monthly, fuel supply is adequate (8+ hours), and transfer time meets NFPA 110.
References & Sources
- IEC 60364 — Low-Voltage Electrical Installations
- BS 7671:2018+A2:2022 — Requirements for Electrical Installations (IET Wiring Regulations)
- NFPA 70E — Standard for Electrical Safety in the Workplace
- NFPA 110 — Standard for Emergency and Standby Power Systems
- DPDC — Dhaka Power Distribution Company
- BNBC 2020, Part 8 — Building Electrical Installations (HBRI, Government of Bangladesh)
- UK HSE — Electrical Safety Guidance
Insights & Guidance
- Electrical faults are the leading cause of building fires worldwide.
- Earthing resistance: ≤ 5 Ω general, ≤ 1 Ω for lightning protection and data centres.
- Insulation resistance: ≥ 1 MΩ at 500V DC test — below this indicates degradation.
- RCDs/RCCBs on all socket circuits are a minimum safety requirement — many Bangladesh buildings lack them.
- Annual thermographic survey of switchgear is cost-effective fire prevention.
- Generator transfer time ≤ 10 seconds, fuel autonomy ≥ 8 hours for commercial buildings.
- Periodic electrical installation testing (EICR) every 5 years per BS 7671 — rarely done in Bangladesh but essential.
Electrical failure modes are severe: electrocution kills instantly, arc flash causes explosive burns at temperatures exceeding 19,000°C, and electrical fires can spread rapidly through cable routes and risers. Unlike structural or seismic risks, electrical hazards are present every day — not just during extreme events.
In Bangladesh, electrical fires are the most common cause of commercial building fires. Informal wiring modifications, overloaded circuits, corroded connections, and lack of earth protection create persistent hazards. For MNC occupiers, an electrical installation condition report (EICR) is a baseline requirement — it identifies every deficiency in a single survey.
- Electrocution — fault current flowing through a person to earth. Caused by damaged insulation, missing earth connection, or absence of RCD protection. 30 mA for 30 ms can kill.
- Arc flash — explosive electrical fault releasing extreme heat (19,000°C+), light, pressure, and molten metal. Most common at switchboards during operation or maintenance.
- Electrical fire — overloaded circuits, loose connections, deteriorated insulation generate heat that ignites surrounding materials. Often starts in concealed locations (within walls, above ceilings).
- Voltage instability — under-voltage damages motor windings (compressors, pumps), over-voltage damages electronics. Both common in Bangladesh grid supply.
- Generator failure — ATS doesn't transfer, batteries dead, fuel exhausted, cooling failure. Critical operations lose power during grid outage.
- Lightning damage — without proper lightning protection and surge protection, a direct or nearby strike can damage electronics, fire alarm panels, lift controllers.
- Electrical Installation Condition Report (EICR) — or equivalent periodic inspection report per BS 7671 / IEC 60364-6. Every 5 years or at change of occupancy.
- Single Line Diagram (SLD) — up-to-date electrical distribution diagram showing main incoming, transformers, generators, switchgear, distribution boards, major loads.
- Earth resistance test certificate — annual test per BS 7671 / IEC 60364. Shows measured values at each earth electrode.
- Lightning protection test certificate — annual test per IEC 62305 / BS EN 62305. Earth resistance ≤ 1 Ω for each down-conductor.
- Thermographic survey report — annual thermal imaging of switchgear and distribution boards.
- Generator test records — monthly load test, annual full-load test, ATS transfer test, fuel quality check.
- RCD test records — quarterly press-test by building staff, annual instrument test by electrician.
- Exposed or damaged wiring — especially surface cables, taped joints, cables through door frames.
- Overloaded socket outlets — multiple adapters, extension leads daisy-chained.
- Distribution boards with missing covers, exposed bus bars, signs of heat damage.
- Switchgear room housekeeping — stored materials near switchboards, lack of access clearance.
- Absence of RCDs on socket circuits — check the distribution board schedules.
- Earth bonding — are metallic services (water, gas, structural steel) bonded to the earthing system?
- Generator room — fuel leaks, exhaust routing (not into occupied spaces), battery condition.
- Arc flash warning labels on switchgear — absence indicates no arc flash study has been done.
- Smell of burning or electrical ozone near distribution boards.
- When was the last electrical installation condition report (EICR) or periodic inspection conducted? What were the findings?
- What is the measured earth resistance? When was it last tested?
- Are RCDs/RCCBs installed on all socket circuits? When were they last tested?
- Is the single-line diagram (SLD) up to date — does it reflect all current loads and modifications?
- Has a thermographic survey of switchgear been conducted in the last 12 months?
- What is the generator capacity (kVA), fuel autonomy (hours), and transfer time (seconds)? When was the ATS last tested?
- Has an arc flash study been conducted per IEEE 1584 / NFPA 70E?
- Is there a lightning protection system? When was it last tested and what was the earth resistance?
- Have any electrical modifications been made since the last inspection? Were they designed and certified?
- Pre-lease or pre-purchase due diligence — electrical survey (EICR) by chartered/licensed electrical engineer.
- Any C1 (danger present) finding on an EICR — immediate remediation by qualified contractor.
- Arc flash hazard analysis — required for any switchboard above 240V where maintenance is performed.
- Generator sizing or replacement — electrical engineer to conduct load analysis and specify equipment.
- After any electrical incident (shock, arc flash, fire) — investigation by qualified specialist.
- Major renovation or fit-out — electrical design by professional to ensure compliance and adequate capacity.