Multiple Earthing System

Multiple Earthing System Points : multiple earthing system A TN-C-S system is as the TN-S but the supply cable sheath is also the neutral, i.e. it forms a combined earth/neutral conductor known as a PEN (protective earthed neutral) conductor.

The installation earth and neutral are separate conductors.

Earth Resistance Value

Earth Resistance Value Points : earth resistance value, what are the factors on which earth resistance value depends? how earth resistance can be reduced? Earth resistance value depends upon:
a) Condition of Soil.
b) Moisture of the soil
c) Temperature of the soil.
d) Depth of the electrode at which it is embedded.
e) Size and spacing of earth electrodes.

What Points are To Be Connected To Earth?

What Points are To Be Connected To Earth? Points : what points are to be connected to earth? The following equipment should be connected to earthing through earth wire as per Electricity Rules.

i) The neutral conductor of 3 phases. 4 wire a.c. electrical system and the middle conductor of two phase, 3 wire system should be earthed by not less than two separate and distinct connections with earth at the generating station and at the sub-station.

Functions of Earthing

Functions of Earthing Points : Functions of Earthing Earthing may be defined as the process of connecting the non-current carrying parts of electrical apparatus to the general mass of the earth in such a manner that at all times an immediate discharge of electrical energy place without any danger.

Specifications of Earth Wire and Earth Plate

Specifications of Earth Wire and Earth Plate Points : specifications of earth wire and earth plate, (i) Specifications of Copper Earth Plate: 60 cm x 60 cm x 3mm high conductivity copper plate fitted with copper lug. bolt, nut and washer. The finished plate shall have reasonably clean and smooth surface, free from scratches. porosity, black oxide and any other defect.

Material Required For GI Pipe Earthing

Material Required For GI Pipe Earthing Points : material required for gi pipe earthing The list of material with complete specifications for GI pipe earthing is given below

Determination of Size of Earth Wire And Earth Plate for Domestic And Motor Installations

Determination of Size of Earth Wire And Earth Plate for Domestic And Motor Installations Points : determination of size of earth wire and earth plate for domestic and motor installations In case of I w voltage supply, the consumer need not provide his own earthing system, with an independent electrode as the supplier is required to provide and maintain a suitable earthed terminal in an accessible position at or near the point of commencement of supply at the consumer premises. Hence earth plate is not-required on submain distribution boads for connecting each terminal provided on submain distribution boards to the earthing terminal provided by the supplier on main distribution board.

Earth Continuity Conductor

Earth Continuity Conductor Points : earth continuity conductor This is the part of the earthing system which joins or bonds together all the metal parts of an installation: Conduit, ducts, boxes, metal casing of switches, switchfuses, fuse distribution boards,

Installation with High Resistance of Earth

Installation with High Resistance of Earth Points : installation with high resistance of earth Danger now exists on the exposed metalwork because the fault current of 4.2 amps flow through a resistance of 50 ohms in the install the metalwork and earth. The first indication that a fault has occurred is when someone earth. The first indication that a fault has occurred is when someone touches the metal work and gets a severe or possibly fatal shock.

Points To Remember While Providing Earthing

Points To Remember While Providing Earthing Points : points to remember while providing earthing Following point should be remembered while providing earthing to an installation and premises. Various details given as per I.S. specification are: (i) Distance The distance of the electrode from the installation at the premises should be more than 1.5 meter.

Selection of Fuse Wire

Selection of Fuse Wire Points : selection of fuse wire, Cable and Fuse Ratings for Motors The fuse rating for steady load circuits such as heating loads should be equal to or next greater than the rating of smallest cable in the circuit. For fluctuating load circuits like those of motor, capacitor and transformer loads fuse should have such current-time characteristic as to allow the short time over current to flow without blowing. For this it is sometimes necessary to select fuses of rated current greater than that of the cable of the circuit, In motor circuit fuse is to be rated for short circuit and not for over current protection which is looked after by over current protection provided in starter.

Comparison of HRC Fuse and Circuit Breakers

Comparison of HRC Fuse and Circuit Breakers Points : comparison of hrc fuse and circuit breakers (i) HRC fuse possess higher rupturing capacity compared to Circuit breakers in the medium voltage range. Fuses with rupturing capacity of 75 MVA (breaking current app. 100 KA) arc available Breakers with corresponding capacity will be too bulky.
(ii) HRC fuses are cheaper than the circuit breakers.
(iii) HRC fuse take less space and are simpler to install and maintain.