Page 52 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Pig-tail/Rat-tail/Twisted joint: (Fig 1) This joint is suitable for pieces where there is no mechanical stress on
the conductors, as found in the junction box or conduit accessories box. However, the joint should maintain good
electrical conductivity.
Married joint: (Fig 2) A married joint is used in places where appreciable electrical conductivity is required, along
with compactness.

Fig 1 Fig 2

As the mechanical strength is less, this joint could be used at places where the tensile stress is not too great.
Tee joint (Fig 3): This joint could be used in overhead distribution lines where the electrical energy is to be
tapped for service connections.

Britannia joint: (Fig 4) This joint is used in overhead lines where considerable tensile strength is required.
It is also used both for inside and outside wiring where single conductors of diameter 4 mm or more are used.

Fig 3 Fig 4

Britannia tee joint: This joint (shown in Fig 5) is used for overhead lines for tapping the electrical energy
perpendicular to the service lines.
Western union joint (Fig 6): This joint is used in overhead lines for extending the length of wire where the joint
is subjected to considerable tensile stress.

Fig 5 Fig 6

Scarfed joint (Fig 7): This joint is used in large single conductors where good appearance and compactness are
the main considerations, and where the joint is not subjected to appreciable tensile stress as in earth conductors
used in indoor wiring.

Tap joints in single stranded conductors of diameter 2 mm or less : By definition, a tap is the connection of
the end of one wire to some point along the run of another wire.
The following types of taps are commonly used.

– Plain
– Aerial
– Knotted
– Cross - Double - Duplex

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CITS : Power - Electrician & Wireman - Lesson 5 - 12 CITS : Power - Electrician & Wireman - Lesson 5 - 12