Page 123 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Rule 50: Energy shall not be supplied, transformed,converted or used unless the following provisions are
observed. A suitable linked switch or circuit breaker is erected at the secondary side of the transformer. Every
circuit is protected by a suitable cut-out. Supply to each motor or group of motors is controlled by a linked
switch or circuit breaker. Adequate precautions are taken to ensure that no live parts are exposed.
Special provisions in respect of high and extra high voltage installations
Rule 63: Approval of Inspector is necessary before energising any high voltage installations.

Rule 65: The installation must be subjected to the prescribed testing before energizing.
Rule 66: Conductors shall be enclosed in a metallic covering and suitable circuit breakers shall be provided to
protect the equipment from overloading.

Rule 68: Incase of outdoor type of sub-station a metallic fencing of not less than 1.8 m height shall be erected
around the transformer.
Provisions in terms of OH line
Rule 77: Clearance of lowest conductor above ground across street.

• Low and Medium Voltage lines - 5.8 m.
• High voltage Lines - 6.1 m.
• Clearance of lowest conductor above ground along a street. Low and Medium Voltage lines - 5.5 m.
• High voltage lines - 5.8 m.

• Clearance of lowest conductor above ground other than along or across the street. Low, Medium and High
Voltage lines upto 11 KV if bare - 4.6m .
• Low, Medium and High upto and including 11KV, if insulated - 4.0m.

• High Voltage above 11 KV - 5.2 m.
Rule 79: Clearance of low and medium voltage lines from building,
• Vertical Clearance - 2.5 m.
• Horizontal clearance - 1.2 m.
Rule 80: Clearance from building of high and extra high voltage. Vertical Clearance High Voltage upto 33KV
- 3.7m.
• Extra High Voltage above 33KV - 3.7 m, plus 0.3 m for every 33KV part there of.
• Clearance from building of high and extra high voltage - Pitched Roof . Vertical Clearance upto 11KV - 1.2m.
• Above 11KV upto 33KV - 2.2 m.

• Above 33KV - 2m. plus 0.3m for every 33KV part there of.
Rule 85: Maximum interval between supports. It shall not exceed 65 m except by prior approval of inspector.
Indian electricity rules regarding to internal wiring:
1 The minimum size of conductor used in domestic wiring must not be of size less than 1/1.12mm in copper or
1/1.40mm (1.5mm) in aluminium wire.
2 For flexible wires the minimum size is 14/0.193mm.
3 The height at which meter board, Main switch board are to be fitted 1.5 meters from ground level.
4 The casing will be run at a height of 3.0 meters from the ground level.

5 The light brackets should be fixed at a height of 2 to 2.5 meters from ground level.
6 The maximum number of points in a sub circuit is 10.
7 The maximum load in a sub circuit is 800W.

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CITS : Power - Electrician & Wireman - Lesson 20-25