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.
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/-
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.
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
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:
- Online free, Consumer Guide, www.electricalsafetyfirst.org.uk.
- 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/
- www.theiet.org: British Standards, “Recommendations of Electrical Installations, BS7671 2018 and 9 guides.
- 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.
