This document provides information about different types of electrical supplies and connections including: 1. Single phase and three phase alternating current supplies, as well as direct current supplies. Practical voltage measurements of different sources are listed. 2. Types of wire joints for electrical connections including straight and tee joints. 3. The concept of earthing electrical circuits to direct leakage current safely into the ground.

1. Electrical
Workshop
(Incl. Household Wiring)
Prepared By : Makineedi Venkat
Roll No:16BE01043
Chemical Engineering

2. Electric Supply
Electric
Supply
Alternating
Current
Single
Phase
Three
Phase
Direct
Current
The Electric supply can be categorized as follows:
 In India, range of single
phase supply is about
240V and frequency is
about 50Hz.
 Single phase connection
consists of a live wire and
a neutral wire.

3. Source Voltage
New Cell(AA Type) 1.435V
New Cell(AAA Type) 1.567V
Mobile Battery(Samsung 3000mAh) 4.04V
Power Bank(Not Fully charged) 2.5V
Discarded UPS Battery 0.610V
New Battery(9V) 9.63V
Used Battery(9V) 0.581V
Direct Current
 Energy is supplied by voltage difference between terminals by chemical
reactions or by rectifying AC Supply.
 Supply is checked by diode or multimeter/voltmeter.
 Practically tested voltage of some sources:

4. Alternating Current(AC)
 Gained from alternator(AC Generator), a mechanically operating device
to obtain alternating current by rotatory coil in magnetic field, rotated
by external force.
 Live wire is checked by tester etc.
 Whereas supply is checked by test lamp, etc.
 While practical testing, the single phase supply voltage at the location
was 251V, measured by voltmeter.

5. Types of Wire Joints
 While performing practically, wire joining is of broadly of two types:
1. Straight Joint
2. Tee Joint

6. Concept of Earthing
 Concept of Earthing comes into the picture when leakage current is present in
an electrical circuit.
 Leakage current might create faulty device or open circuit or shocky circuit.
This problem is solved by earthing this current. The current is flowed down
the earth by physical connection.
 It is of two types:
1. Pipe earthing.
2. Plate earthing.
 As their names suggest, plate earthing has a Copper or Iron plate for earthing
whereas has pipe earthing has pipe connected.
 Earthing is done by digging out and filling the plate/pipe entirely(whole
plate/bottom pipe) by coal and salt below 1/1.5m with regular water
feeding.

8. Three Phase Voltage
 Three phase supply has three single phase supply together.
 Represented as its color code : RYB i.e., Red, Yellow, Blue.
 It has 4 wires. Three phase wires and a neutral connection.
 Supply voltage is about 440V, according to respective phaser diagram.
 Practically checked data:
Connections Voltag
e
Connections Voltage
R-N 247.0V R-E 246.1V
Y-N 246.4V Y-E 246.3V
B-N 250.0V B-E 250.8V
R-Y 425V N-E(Site A) 1.09V
Y-B 430V N-E(Site B) 7.48V(Faulty Earthing Connection)
R-B 426V N-E(Site C) 0.7V

9. Switches, MCB, MCCB, ELCB/RCCB,
 Types of Switches:
1. Single Phase (1 Pole, 2 Pole)
2. Three Phase (3 Pole, 4 Pole)
 Here poles can be considered as terminals
 MCB - Miniature Circuit Breaker( upto 63A)
 MCCB – Moulded Case Circuit Breaker( Beyond 63A)
 RCCB/ELCB – Redual Current CB/ Earth leakage CB( Safety purpose for leakage current)
 These are safety switches which get automatically OFF at high current flow/high
voltage by triggering the switch, operating on basis of thermal property of material
used.

10. ON – OFF Switch(Normal/Single Pole Switches)
 These are basically single pole single throw/one way and single pole
dual/double/two way switch.
 There are two contacts. One connected directly to mains is called main
contact whereas the one contacted with device is called OFF wire.
 Switches belong to controlling components.
 Single Pole Two way switch is used for staircase/godown wiring purpose.

11. Series – Parallel Combinations
 Various combinations of various electrical components can be created by
series/ parallel connections.
 A Lamp Connection example is shown.

12. Series Parallel Testing Board
 It is a self prepared testing board for the following tests:
1. Body Earth
2. Short Circuit Test
3. Close Circuit Test
 Some times not all tests can e performed in normal conditions. If short circuit is
possible, then we have to test it in series condition to prevent a major short
circuit. Whereas Body Earthing tests can be performed in parallel combination.
 Following is a series parallel board:

13. Winding in Motors
 Single Phase motor has two windings, namely, Running Winding and Starting
Winding. Their functions are as per their name.
 It needs a capacitor to start for extra starting torque.
 Three Phase motor does not require a capacitor to start.
 A three phase motor has three coils each working on each phase i.e., R, Y, B
and internally connected by STAR/DELTA connections.