Its all About EARTHING Know more about Earthing.

A Presentation By: Earthing Solutions

Role of Earthing in Electrical Disaster Management • Electrical Hazards • Electrical Safety • Objectives of Earthing • Need of Earthing • Working of Earthing • Qualities of Good Earthing • Rules & Code of Practice for EARTHING. • Testing & Measurement of Earthing • Maintenance of Earthing • Reports & Records K

1. Electrical Hazards

• It is not fun; Electricity kills a great many people Worldwide every year.

• Electricity is often overlooked as a possible fire hazard. May be this is because there is no flame. However, some 28,000 fires in the home are reported each year as being caused by electrical faults, accidents or by misuse of electrical equipment.

• Electrical Safety leads to Fire Safety.

1.1 Reasons for Electrical Hazards

Main causes of Electrical accidents are:-

• Lack of maintenance. • Failure or lack of Earthing. • Unsafe and careless operating procedures. • Electrical wiring and equipment's physical

form could have been damaged. • Incorrectly connected wires and other

mistakes are usually caused by ignorance or negligence.

2.1. Electrical Safety Means • Out of three points Phase, Neutral and Earth, Only Phase

(+) is switched off. Neutral (-) and Earth remains in the system.

• Due to return current it shows voltage between Neutral and Earth.

• Even in switched off condition this voltage remains in the system. • Voltage between Neutral & Earth should always be Less

than 2 Volts. • If Voltage between Neutral & Earth increases it causes

heating of insulation of cable and ultimately the Short Circuit.

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2.2. Electrical Safety Means

• Personal Safety: Means anticipating a high risk situation and moving to a low risk location.

• Structural Safety: Means using various exterior an interior defensive systems in a detailed, site specific process.

sl. Current Range Effects

1 ~ 1mA - 2mA No harmful effects 2 ~ 5mA - 10mA Painful and burning sensation 3 ~ 10mA - 15mA Muscular contraction 4 ~ 20mA - 30mA Impairs breathing or having breathing difficulties 5 ~ 40mA & above Ventricular fibrillation or death

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3. Objectives of Earthing • To ensure safety of life and property from hazards of electric shock and electric fires. • To ensure that system voltages on healthy lines remain within reasonable limits under fault

Conditions thereby preventing insulation breakdowns. • To provide a low impedance path (safe path) to dissipate lightning and short circuit currents. • To minimize arcing burn downs as in an earthed system arcing fault would produce a current in

ground path thereby providing an easy means of detecting and tripping against phase to earth arcing fault breakdowns.

• To provide stable platform for operation of sensitive electronic equipments i.e. To maintain the voltage at any part of an electrical system at a known value so as to prevent over current or excessive voltage on the appliances or equipment.

• To provide an alternative path for induced current and minimize the electrical noise in cables. • To provide protection against static electricity from friction.

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4. Need of Earthing

• Besides human safety risks, sensitive computers and electronics devices fail to operate properly and/or sustain damage at lower voltages which usually cannot be felt by humans, resulting in loss of productivity and expensive troubleshooting & repairs.

• Current also passes through the least path. In case of fault current, short circuit there is two options available for its dissipation into the earth:

Current may take the path of earthing or Current may take the path of human body of the affected person

• This depends on the least resistance of path between the two. Hence the resistance of the earthing should be always be lesser than the resistance of the human body.

• Earthing is absolutely necessary to protect human life and equipment from electrical hazards in this electronic age.

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5. Working of Earthing

• The case (chassis) of the equipment is connected to an earth pin on the mains outlet. This is then connected through the house wiring and switchboard to an electrically solid earth point, which is called EARTHING or GROUNDING.

• Should a fault develop within the equipment that causes the active (live) conductor to come into contact with the chassis, the fault current will flow to earth, and the equipment or main switchboard fuse or circuit breaker will blow. This protects the user from electric shock, bypassing the dangerous current directly to earth, rather than through the body of the unsuspecting person who just touched it.

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6. Qualities of Good Earthing

• There are various formal definitions of a good Earthing, e.g., how many amp of current it can drain at a particular voltage, or resistance per surface meter.

• Good Earthing must have impedance low enough to ensure that sufficient current can flow through the safety device so that it disconnects the supply ( <0.4 sec ) and that voltage of earth doesn't rise more than 50V.

• In simple theory this will prevent a potential difference between earth and earthed parts, as well as permitting the flow of fault current which will cause the operation of the protective systems.

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7. Rules & Code of Practice

The Indian Electricity Rules, 1956 &

Indian Standard CODE OF PRACTICE FOR

EARTHING IS:3043:1987

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7.1. The Indian Electricity Rules, 1956 Rule: 33

Earthed Terminal on consumer’s premises:- • The supplier shall provide and maintain on the consumer’s premises for the

consumer’s use, a suitable earthed terminal in an accessible position at or near the point of commencement of supply as defined under rule 58.

• Provided that in the case of medium, high or extra-high voltage installation the consumer shall , in addition to the aforementioned earthing arrangement, provide his own earthing system with an independent electrode.

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7.2. The Indian Electricity Rules, 1956 Rule: 67/5-b

• Every earthing system belonging to either the supplier or the consumer shall be tested for its resistance to earth on a dry day during dry season not less than once a year.

• Records of such tests shall be maintained and shall be produced, if required before the Inspector or any officer appointed to assist him and authorised under sub- rule (2) of rule 4A.

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7.3. Indian Standard CODE OF PRACTICE FOR EARTHING IS:3043:1987

Code: 34. MAINTENANCE OF EARTH ELECTRODES Code: 34.1

It is recommended that periodical check tests of all earth electrodes should be carried out. Records should be maintained of such checks.

Code: 34.2

Where earth-leakage circuit-breakers are em­ployed, a check shall be kept on the associated earth-electrode by periodically operating the testing device which is embodied in the earthed- leakage circuit-breaker.

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7.4. Indian Standard CODE OF PRACTICE FOR EARTHING (IS:3043:1987)

Code: 34. MAINTENANCE OF EARTH ELECTRODES Code:34.4 Substations and Generating Station*

Code:34.4.1 Records shall be kept of the initial resistance of substation and generating station earth electrodes and of subsequent tests carried out.

Code:34.4.2 Normally annual measurement of earth resistance of substation shall be carried out but local circumstances in the light of experience may justify increase or decrease in this interval but it should not be less than once in two years.

Code:34.4.3 Periodical visual inspection of all earth electrode connection, wherever available, shall be carried out to ensure their rigidity and other signs of deterioration.

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8. Testing & Measurement of Earthing

• The Para meter of the EARTHING is resistance and it’s Unit is Ohm

• At any point of time earth resistance should not increase more that 2 ohms the resistance of a human being.

• If it increases 2 ohms, it can be hazardous & fatal.

• Regular testing of EARTHING is very important.

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9.1. Maintenance of Earthing System OUR SERVICES:

Assessing the technical efficacy of existing earthing system:

Methods:

(I)Measurement of Earth pit resistance:-

• The 3 Point Method Fall of Potential test: (OR)

• Clamp-on Method for individual and loop resistance.

(ii) Measuring potential difference between neutral of the power supply to Earth at various locations.

(iii) Continuity Test.

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9.2. Maintenance of Earthing

Suitability of the existing system:

(I) Examining whether cable/strip of proper material and size has been used for the earthing.

(ii) Examining whether joints are proper. (iii) Whether the system is working o.k.? (iv) Whether it needs any correction? (v) Whether it can be revived? (vi) If not, what solution?

Corrective actions: (I) Improving conductivity of earth. (ii) Cleaning/ replacing the rusted

plates/wires nut-bolts. (iii) Replacing broken earthing

plates/wires and nut-bolts etc.

OUR SERVICES:

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9.3. Maintenance of Earthing OUR SERVICES:

Providing Name plate Identifying : • The Site / Location • Number of Earth Pits. • Showing the resistance value • And date of Operation.

Periodicity: • Half-yearly • or quarterly; • or as desired by the customer.

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9.4. Maintenance of Earthing

Consumer satisfaction: Providing a report showing result of

site inspection including Earth resistance and Neutral potential values.

OUR SERVICES:

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9.5. Maintenance of Earthing

Report & Records: • Identification Name Plate of Earthing at the

location.

• Site Report.

OUR SERVICES:

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10. Our Achievements

We are Happy with our achievements but we are Proud to be associated with YOU. We have completed 13 years of Customers service in the field of EARTHING Management with more than 15000 Earthing successfully installed and commissioned across India. We are satisfied that we do not have a single unsatisfied customer in our fold.

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First Step Towards Electrical Safety is to

EARTH the earth...

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