This document provides information on various types of electrical distribution and protection equipment, including fuses, fuse holders, circuit breakers, wires, switches, and wiring methods. It describes the components and characteristics of fuses and circuit breakers and lists common fuse and circuit breaker types. It also discusses different types of wires based on material and use, as well as various wiring methods like cleat wiring, batten wiring, casing capping wiring, and conduit wiring.

1. ELECTRICAL
SERVICES

2. ELECTRICITY :-- Electricity is a general term that
encompasses a variety of phenomena resulting from the
presence and flow of electric charge .

3. Electrical distribution and protection equipments :--
1. Fuses :-

4. A fuse consists of a metal strip or wire fuse element, of
small cross-section compared to the circuit conductors,
mounted between a pair of electrical terminals, and (usually)
enclosed by a non-conducting and non-combustible
housing.
Protect electrical devices and components from overcurrent
and short circuits that occur during inproperly operating
circuits.
When fault current reaches a predetermined magnitude for
a fixed period of time,current flow is interrupted through
melting of an internal element.
Performance rating include voltage rating, current rating,
rated breaking capacity.
Performance characterstic : Fast acting and time lag.
The fuse element is made of zinc, copper, silver, aluminum,
or alloys to provide stable and predictable characteristics.

5. Fuse Types :-
1. Miniature fuse :- Commonly available in dimensions
of
5 x 20 mm and 6.3 X 32 mm

6. 2. Sub-miniature or micro :-
Compact circuit board layout.
Mainly 13-32 inch diameter fuses.

7. 3. Automotive Fuse :-
Automotive fuses are a class of fuses used to protect
the wiring and electrical equipment for vehicles. They
are generally rated for circuits no higher than 24 volts
direct current, but some types are rated for 42-volt
electrical systems. They are occasionally used in non-
automotive electrical products.

8. 4. Blade Type Fuses :-
Plug-in fuses (also called blade or spade fuses), with a
plastic body and two prongs that fit into sockets, are
mostly used in automobiles .
Used in low voltage and high current applications.
Type Dimensions L x W x H Ampere ratings
Mini 10.9 x 3.6 x 16.3 mm
2A, 3A, 4A, 5A, 7.5A, 10A,
15A, 20A, 25A, 30A
Low-Profile Mini 10.9 x 3.81 x 8.73 mm
2A, 3A, 4A, 5A, 7.5A, 10A,
15A, 20A, 25A, 30A
Regular 19.1 x 5.1 x 18.5 mm
1A, 2A, 3A, 4A, 5A, 7.5A, 10A,
15A, 20A, 25A, 30A, 35A, 40A
Maxi 29.2 x 8.5 x 34.3 mm
20A, 30A, 40A, 50A, 60A,
70A, 80A, 100A

9. FUSE HOLDER :- Fuse holder are devices for
containing,protecting and mounting fuses.

10. 1. Open fuse holder :- Open fuse holder types are fuse
claps,
fuse blocks, socket and
plug on cap varieties.
2. Fully enclosed :- Fully enclosed variety may use a fuse
carrier that is inserted into a holder or have other means
to fully enclosed the fuse.

11. Circuit Breaker :- Circuit breaker are switching device
capable of making, carrying and breaking current under
normal circuit conditions and making, carrying for a specific
time, and breaking current under specified conditions such
as a short circuit.
A circuit breaker is an automatically-operated electrical
switch designed to protect an electrical circuit from damage
caused by overload or short circuit. Its basic function is to
detect a fault condition and, by interrupting continuity, to
immediately discontinue electrical flow. Unlike a fuse, which
operates once and then has to be replaced, a circuit breaker
can be reset (either manually or automatically) to resume
normal operation.

12. Actuator lever - used to manually trip and reset the circuit
breaker. Also indicates the status of the circuit breaker (On
or Off/tripped).
Actuator mechanism - forces the contacts together or apart.
Contacts - Allow current when touching and break the
current when moved apart.
Terminals
Bimetallic strip
Calibration screw - allows the manufacturer to precisely
adjust the trip current of the device after assembly.
Solenoid
Arc divider / extinguisher

13. Circuit Breaker

14. TyPES OF CIRCUIT BREAKER :-
Low voltage circuit breaker:--
1. MCB [miniature circuit breaker]:- rate current more
than 100 A.
Trip characterstic normally not adjustable. Thermal
or thermal – magnetic operation.
2. MccB [molded case circuit breaker] :- rated curent up
to 1000 A. Thermal or thermal magnitude operation.
Trip current may be adjustable in large rating.

16. WIRES :- A wire is a single, usually cylindrical, string of
metal. Wires are used to bear mechanical loads and to
carry electricity and telecommunications signals. Wire is
commonly formed by drawing the metal through a hole
in a die or draw plate .

17. Classified based on material :-
Copper :- Very good conductor and is easy to mold and
bend.
Most commonly used.
Reasonable Price.

18. ALUMINIUM :- Cheaper and easy to shape and bend,
A less conductive
material.
Electrical safety is an
issue.
Heating occurs.

19. ALLOYS :- An alloy made from aluminium and copper to
take advantage of both.

20. SILVER WIRES :- Best conductor of electricity .
It is too expensive.

21. CLASSIFICATION BASED ON USE :-
1. Triplex Wire :- It is arial cable uses to fed the power
pole.
Wire ties to the wires
sticking out of the weather
head.

22. 2. Main Feeder wires :- These wires are usually type
THHN wire and rated for 125% of the load required.
These are usually black insulated wires coming out of
the service weather head.

23. Panel Feed Wires :- These wires are also type THHN like
the main feeder . A typical 100 A servicewould have a
THHN set of wires. They would then be rated at 125 A.
This would protect the wires if the amperage was at full
100 A.

24. Non-metallic sheathed wire :- This wire commonly called
Romax. Is a plastic coated wire that has either 2 or 3
conductors.

25. Single Strand wires :- when your home is piped you will
have to have another type of wire. Single strand wire is
insulated and many of these can be pulled into the same
pipe.

26. Bus Bars :- An aluminium or copper conductor supported
by insulators that interconnects the loads and the source
of the electrical power in an electric power system.
1. Rigid bus bars :-Low,medium and high voltage.
Sulphur hexafluoride.

27. Switches :- Devices used to allow electrical current to flow. When
closed and when opened,they prevent current flow.
Common Switch Types :-
Push button
Rocket Rock
Toggle
Dual line
Rotary
Keylock
Slide
Snap action
Reed

28. Wiring :- Electrical wiring in general refers to insulated
conductors used to carry electricity, and associated
devices.
Types of wiring :-
1 . Cleat Wiring:-Types of wiring to be adopted is
depends upon various
factors,duarability,safety,appearance,cost,consumers
budget etc
This system uses insulated cables sub protected in
porcelain cleats.
Recommended only for temporary installations.
Cleats are made in pairs having bottom and top
halves.
initially top and bottom cleats are fixed according

29. Types :- Having 1,2 or 3 grooms to receive 1,2, or 3 wires.
Advantages :-
Cleat wiring is one of the cheapest wiring.
More suitable for temporary installation
When not required the wiring could be dismanteled without
damaging cables,cleats and accessories.
Disadvantages:-
Wiring is exposed chnces of fire are there.
Not appealing
Less durable

30. B.I.S recommendations for cleat wiring :-
Not employed for wiring on damp walls or ceiling
unless precautions are adapted for affectively preventing
dampness.
Class of cables :- vulcanised rubber insulated cables,
pvc and poluthene insulated cables, insulated cables
could be used without any further protection.
Cleats :- All cleats should consist of two parts a
base piece and a cap. Cleats shall be fixed at a distace
more than 60 cm apart and at regular intervals.Cleats
shall be inserted either with varnished wood fillets or
varnished wood clamps.

31. Fixing of cleats :- IN ordinary cases cleats shall be
attached. Cleats shall be such that conductor distance
shall not be less than 2 cmfor pressure upto 250 volts
Branch load :- 2.5 cm apart
Sub-mains :- 4 cm apart

32. Batten wiring :- Tough rubber sheathed or pvc sheathed
cabled are suitable to sum on teak wood battens
Metal sheathed wires are used.
teakwood shall be seasond and wel finished from all
sides. Shall not be less than 10 mm in thickness
battens shall be painted with vanish prior to erection.
Battens shall be fixed to wallas using wall plug or
wooden plug not more than 75 cm
Cables are held on battens.
Link Clip :- use to family clipping the cables in
position.

33. Link Clip :- use to family clipping the cables in position.
link clips are of two types.
made of tin or brass coated tin.
ADVANTAGES :- easy to install.
widely used for indoor installations.
DISADVANTAGES :- Wires are exposed more chances of
damage.
Chances of spreading fire are
more.
not much appealing.

34. Cassing caping wiring :- For low voltage installation.
cables like vulcanised rubber,insulated cables,plastic
insulated cables are used and carried within the wood casing
enclosure
Not to be used in un ventilated or dap places . Unless
precautions are taken.
Material and pattern of casing :-
all casing shall be of fust glass, seasoned teak wood or
any other approved hardwood.
all sides well varnished,both inside or outside shealed
varnish.

35. Advantages :- Wires not fully enclosed ,less chances of
damage.
chances of fire spreading are less
better asthetically appealing.
Disadvantages :-Expensive.
only used in dry places.

36. Conduit wiring :- conduit is defined as a tube or channel.
Tubular conduit is most commonly used installation.
Types of conduit :-
Rigit steel conduit.
rigid non-mettalic conduit.
Flexible steel conduit.
Flexible non mettalic conduit.

37. Surface conduit :- conduit shall be finished with galvanised or
stone surface.
Conduit accesories shall be threaded type and conduit shall be
fixed using screwed couplers and accessories at a distance not
more than 1 m and 30 cm in case of bends.
Diameter not less than 16 cm
For long runs : use inspection type couplers.
Advantages :- Fire protection
Water Proof
easy replacement of defective wires.
Disadvantages :- Expensive wiring
mostly used in factories only.