Prevent Electric Shock and Electrical Fires in Electrical Installation as per Indian standards

- The following article is authored by Gajaria Gokal, B.E. and M.E. (USA)

Electric Shock Fires Prevention Safety

An Introduction:

  • Step by step Guide to “Prevent Shock and Fire in Low Voltage Electrical installation” in residential building and industrial plants as per Indian Standards (IS), Electrical Wiring Code IS732:2019 and Earthing Code IS3043:2018.
  • IS standards are as per International Electrical Commission (IEC), Europe. These are followed in the world.
  • “Electrical shock, Loss of Life and Electrical Fire, Loss of Billions of Rupees and life.”
  • ELCB 30mA: MUST BE 30mA widely use protection against shock.
  • In IEC standard, ELCB is named Residual Current Device (RCD). Cost Rs 1000
  • Danger: This is brief guide for information. Please, take professional advice for any electrical work.
  • Reference 11.2, Electrical Installation Guide as per IEC, 2018, by Schneider Co. Refer to chapters: F and Q

Body resistance and severity of shock:

  • Body resistance: Dry skin is about 5 mega ohms. At 230 V. body 1000 ohms and wet boy 250 ohms.
  • Severity of shock depends: Current flow from hand to hand through heart. Wet body.
  • Current flow in mA and time. Current > 6mA, hand get paralysis and cannot let go hand held items.
  • Maximum voltage person can tolerate in dry location 50V and wet location 25V

Electric Shock Protection:

  • Main Causes: Water, outdoor, open Ground, rough area, touch Earthed metal, water pipes, e.g. Bathroom.

Inside a Flat:

Remedy:

  • ELCB 30mA: Mandatory to install ELCB (Earth leakage Circuit Breaker). All lights and sockets circuits.
  • ELCB and RCBO 30mA: Main purpose shock protection, additional protection against Fire due to earth fault.

High Electrical shock Risk locations: Bathroom and Outdoors:

  • Bathroom:  Our bathrooms are small, about 10’ by 6’.

Cause:

  • Water, bare foot, touching earthed metal water pipes (now, plastic pipes). Water spray.

Remedy:

  • Mandatory: All circuits and light must be protected by ELCB 30mA.
  • NO sockets, light switch, water heater. Light, waterproof to IP44.
  • Exhaust fan 23OV AC, waterproof to IP44 or prefer 12V AC, available in UK.
  • For big size of bathroom with tube, refer to 11.2, chapter Q.

Bathroom Increase Shock Risk Location

Outdoor High Risk Shock

Outdoor:

Cause:

  • Water, barefoot, open ground and may touch electrical metal pole lights.

Remedy:

  • Mandatory: All circuits, lights and sockets, must be protected by ELCB 30mA.
  • All electric items weatherproof to IP44.

RCBO:  MCB+ELCB 30mA

  • Miniature circuit breaker (MCB) for overcurrent, for shock RCD 30mA. (MCB+RCD 30mA). Combine in one device is called Residual Current Circuit Breaker Overcurrent (RCBO).
  • In DB: Option to Install 2 numbers ELCB, each supply numbers of circuits or each circuit with RCBO.
  • 2 numbers ELCB 30mA, disadvantage: If both trips then complete darkness. Person can fell down and hurt.
  • If ELCB trips: To find the fault. Call electrician and time consuming to restore power supply.
  • RCBO Advantage: If nuisance trip of one circuit or trip due to fault. No loss of complete power supply
  • RCBO: Recommend for prestige buildings, high rise buildings, senior citizen homes, schools and etc.

In Europe: RCBO are now commonplace in commercial buildings and growing in popularity in residential.

  • My opinion to install DB with RCBO for each circuit: If RCBO trips in one circuit, no loss of complete power.

Protection by RCBO and AFDD in DB:

  • (MCB+ELCB 30mA) = (RCBO)=Isolation, Overcurrent, Short Circuit, Shock and fire protection from earth fault.
  • (MCB+ELCB 30mA+AFDD) = (RCBOA) = Isolation, Overcurrent, Short Circuit, Shock and Fire Protection from Earth fault and Fire due to Arc.
  • C, Cost of DB with 2 ELCB  30mA or DB with each circuit with RCBO 30mA
  • DB, ELCB 2 number 30mA 4 pole:  Rs. 1500/-   2 numbers Rs. 3000/-. DB cost Rs. Rs. 6000/-
  • DB, each circuit RCBO:  Rs. 1200/- each.  2 Bedroom flat, 10 circuits, cost Rs. 12,000/-. DB cost Rs. 15,000/-
Total Circuits 10 Number
Total Circuits: 10 number
Rcbo 30ma Rs 1200 Afdd
RCBO, 30mA, Rs 1200 AFDD

Electric Fire Protection:

Main Causes: 

  • Arc, Cable arcing ground fault, overload. No correct cable derating factors for temperature and grouping

Combustion Materials storage electrical fire protection:

  • Textiles, wood, papers showroom
  • Remedy: Mandatory to install for fire protection by ELCB 300mA.

Fire due to arc from earth faults.

Cause:

  • The majority of electrical fire are due to arc from leakage current in line-to-earth insulation failures
  • Main and sub main circuits, high resistance ground fault: Leakage current produce arc.

Iec Mandatory Db Rcd

Remedy:

  • Recommend to protect by Ground Fault Protective Device (GFPD), setting at 5% to 10% of full load current.
  • Fire Protection: Residual current monitoring (RCM) due to arc from earth fault:
  • Commercial installations, high rise building and etc. If RCD trips during fault then loss of power.
  • RCM is used as central control indication to know location of fault.
  • As per risk factors, RCM make sense to install. Manufactures’ advice.
  • Electrical Fire Presentation Guide: By Schneider Electric co, France.
  • Online download, free, PDF file:  Guide, as per IEC, by Schneider Electrical Company, France. Path

6 Arc Fault Detection Device (AFDD): Protection against Fire from arc:

  • Arc Fault Detection Device (AFDD): Prevent fire due to ARC.  Not in Indian Standard.
  • RCBO 110V: In USA, National Electrical Code (NEC): Mandatory since 2009 in residential flats. Cost Rs. 2000/-
  • RCBO 23OV: IEC Recommends since 2012 for prestige Buildings, High Rise buildings and etc., cost Rs 8000/-
  • IEC highly recommends for Combustion Materials Storage: textiles, woods, plywood and papers and etc.

Why AFDD to install in DB?

  • Fire has the potential to put hundreds of occupants at risk within a matter of seconds. And when it comes to protecting life and property, there’s no room for compromise.
  • Beyond the risk to safety and life, fires can also have a major financial impact.
  • With demand for electrical power on the rise, arc fault protection must shift from a “luxury” to a must.
  • As per my opinion, at least, prefer to install for sockets circuit as per risk factors.
  • B, Video: From Eaton Company, on you tube. Path: https://youtu.be/UtOmau4ym1Q or Google Eaton+AFDD

Protection Against Arc In Flat

Standards guide-books. Training of electricians and engineers:

  • Indian Standards and IEC Standards: There are no guides book or training. How to understand?
  • I am familiar with British Standards 7671:2018, “Recommendation for Electrical Installation” and “National Electrical Code (NEC), USA”.
  • BS7671:2018 is as per IEC standard, have 9 Guides and online training. Refer to www.electrical.theiet.org.

Electricians training as per standard and examinations to get license:

  • “Building Regulations Electrical Work Standard” UK for electricians. This is developed for Building.
  • In UK, there are many private institute schools for online training for electricians and Engineers.
  • In UK, Electricians to pass examinations and license to work. In India, this is not required.
  • Introduce Electrical Installation course in college for Engineers and electricians as per Indian Standards
  • Training, pass examination and license for Electricians to work
  • Regulations and standard for electrical installation in Residential Building as in UK.

Summary:

  • SHOCK: Mandatory, ELCB 30mA or RCBO 30mA for all lights and sockets circuits. Cost Rs 1000/- each

ELCB 30mA:  Main purpose protection against shock. Additional protection against fire from earth fault.

  • FIRE: Mandatory, combustion Materials storage: Textile, wood, papers. To install 300mA RCD, Rs. 5000/-

Arc fault Protection Device (AFDD): Prevent fire due to ARC in the flat. Cost Rs. 8000/ each.

  •  Leakage Current Residual Current Monitoring (RCM) Alarm: Center control indications: Recommend to install in commercials and high rise for alarm against ARC due to earth leakage current.

References:

  1. Online free, Consumer Guide, www.electricalsafetyfirst.org.uk.
  2. Online free, “Electrical Installation Guide to IEC, 2018”, Schneider Electric, France, 500 Page. Design Guide.
  • Go to general contents, page 5 (7/535). Click, Chapters F, Protection against electric shocks and electrical fires. Chapter Q, Residential premises and other special locations, (High shocks risk).
  • https://www.se.com/ww/en/work/products/product-launch/electrical-installation-guide/
  1. www.theiet.org: British Standards, “Recommendations of Electrical Installations, BS7671 2018 and 9 guides.
  2. Book, free online or Amazon: “Guide to the Wiring Regulations 17th Edition IEE Wiring Regulations (BS 7671: 2008)”. By Electrical Contractors’ Association (ECA), UK. Written by practical engineers. Rs.2,500.

Mobile Applications:

  • “Electrical Calculations”, by Ettore Galine: Free online, Pro Rs 190. Cable size and etc.
  • Mobile Electrician”: Anatolly Trasenko, Click IEC, Pro version, Rs. 120.

LEAVE A REPLY

Please enter your comment!
Please enter your name here