Difference between single phase wiring and three phase wiring
DIFFERENCE BETWEEN SINGLE PHASE
WIRING ANDTHREE PHASE WIRING
Group Member: Penny Leung
Tan Shen Shin
Lim Hao Zheng
Benson SowWei Henn
• The single phase requires two wires for
completing the circuit, the conductor and the
• Peaks in voltage at 90⁰ and 270⁰, with a complete
cycle at 360⁰ (see chart below.)With these peaks
and dips in voltage, power is not delivered at a
• The single phase supplies the voltage up to 240
volts. It is mostly used for running the small
appliances like a fan, cooler, grinder, heater
• The three phase system consist four wires, three
conductors and one neutral.
• is continuous and never completely drops to zero.
• All three phases of power have entered the cycle by 120⁰.
By the time a complete cycle of 360⁰ has completed, three
phases of power have each peaked in voltage twice
• In basic terms, three-phase electricity means that
electricity is delivered to your house using three power
lines instead of one.
• Makes your house less risk to blackout
• Usually suitable for larger homes such a bungalows or
DELTA CONNECTION STAR CONNECTION
SINGLE PHASE SUPPLIES THREE PHASE SUPPLIES
• Take single lane highway as an example.
• Voltage power provided is limited
• Take multiple or 3 lanes highway as example.
• Voltage power provided is extremely high and
running multiple appliances in parallel.
50Hz Single phase 240V
3 phase wiring
Advantages of Single PhaseWiring
- The conductor can be quite lightweight and compact in size,
which also results in the supporting tower becoming lighter. The
unit is, overall, quite a portable one.
- The efficiency of the transmission increases, ensuring that the
unit operates at its optimum.
- The substations can also be located near to the high voltage
grid, which reduces the initial cost of transmission.
Disadvantages of Single PhaseWiring
- Insulation depends on the voltage of the unit, whilst the size of
the wire will depend on the current. So, whilst the motor will run
quite efficiently, it will be costly to insulate.
- This is a result of the frequency and can affect operation quality.
- If your application is likely to overload the system, this is not
the best motor choice and you would be better off looking
1. For transmitting the same amount of power at the same voltage ,a three phase transmission line
requires less conductor material .
2. 3-phase induction motor is self-started and is more efficient .
3. High in power to weight ratio .The size of 3-phase alternator is small and the overall cost of the
alternator is reduced for the generation of power .
4. The instantaneous power is always constant which results in smooth and vibration free operation
of machine .
ADVANTAGES OF THREE PHASE WIRING
1. High cost in repairing and to restore the service ,the spare unit cost is high when the 3-phase
transformer is not working .
2. Failure of one phase puts the entire transformer out of service .
3. Complex system ,requires symmetrical components for analysis and operation .
DISADVANTAGES OFTHREE PHASEWIRING
• Single phase wiring system Three phase wiring system
“Generally, if you have 3 or fewer air-conditioning units, and each are between
1 – 1.5 horsepower, you should be fine with single-phase power. But if the
horsepower of your ACs are higher, consider changing to three-phase to
prevent power trips” – Ganesan, an electrician from Megah Global Electrical
Why should you go for three phase
wiring instead of single phase wiring?
The cost to install and maintain three-phase systems is substantially lower than that
of single-phase systems.
Three phase so you can split the loads, first phase is for lighting and fans etc; Second
phase is for mix, grinder,TV, and others;Third phase is for AC, Inverter system etc
This makes your house less at risk of a blackout. If one of the power lines stops
delivering power to your estate, your house may still have power because the other
two lines may not be affected, hence you would get continuous power supply.
“To upgrade from a single-phase power supply to a three-phase power, you
will need to apply throughTenaga Nasional (TNB) as they will be the ones
who will send contractors to test and evaluate whether if upgrading to
three-phase power is a feasible option”.
The upgrading process can take up to three weeks and the cost may
starts from RM2,000 and can go as high as RM10,000 depending on
the size of your house.