The document discusses electric supply systems for small and large buildings. For small buildings, electric power is delivered via a service transformer to the main panel, which then distributes power through branch circuits. For large buildings, the service transformer is in a vault, and the main distribution panel is in an electric room. Feeder cables then send power to local lighting and power panels. Large buildings also have emergency lighting on separate circuits powered by an alternate source. Distribution systems are classified as direct current or alternating current, with AC systems using primary and secondary distribution at different voltage levels to deliver power to consumers.

1. ELECTRIC SUPPLY SYSTEMS
TINA S. KEDIA
ROLL NO 19
BUILDING SERVICES

2. The electrical energy is produced at generating stations, and
through the transmission network, it is transmitted to the
consumers. Between the generating stations and the distribution
stations, three different levels of voltage (transmission, sub-
transmission and distribution level of voltage) are used.

3. Small buildings are served with electric power by service transformer mounted
either on a utility pole or on grade. After passing through meter electricity enters
the main panel where it is control through switches and circuit breakers. The main
panel then distributes the power throughout the building by means of branch
units
ELECTRIC DISTRIBUTIONS IN SMALL RESIDENTIAL
BUILDINGS

4. The service transformer for a large building is placed in a ventilated fireproof vault
while main distribution panel is located in electric room. Feeder Cables then send
power to local lighting and power panels distributed around the building
ELECTRIC DISTRIBUTIONS IN LARGE BUILDINGS
In large buildings the main electrical room contains a meter and a current
transformer Which Is required when metering large amounts of power

5. The electric riser diagram shows the logic for distributing power in large
buildings. The branch circuits from the lighting and power panels are not
shown for the sake of clarity. Emergency lighting and exit signs are powered
from separate circuits so that when main power is lost or turned off the
emergency circuits receive power from another source.
ELECTRIC DISTRIBUTIONS IN LARGE BUILDINGS

6. According to nature of current, distribution system may be classified as:
Direct current (DC) distribution system
Alternative current (AC) distribution system.
The AC distribution system is classified into:
Primary distribution system and
Secondary distribution system.
Primary distribution system
It is that part of AC distribution system which operates at voltages somewhat
higher than general utilization and handles large blocks of electrical energy than
the average low-voltage consumer uses
Power is supplied to various substations for distribution or to big consumers at
this voltage. This forms the high voltage distribution or primary distribution
Secondary distribution system
It is that part of AC distribution system which includes the range of voltages at
which the ultimate consumer utilizes the electrical energy delivered to him.
The secondary distribution employs 400/230 V, 3-phase, 4-wire system. The
primary distribution circuit delivers power to various substations,
called distribution substations.

7. Biblography
https://circuitglobe.com/single-line-diagram-of-power-supply-system.html
https://electrical-engineering-portal.com/electrical-distribution-systems#ac-distribution
Book- plumbing, electricity and acoustics, sustainable methods for architecture by
Norbert m. Lechner