which suppply is used for houses 3 phase or single phase ? how 3 phase is used for lighting loads?

Answer 1

Depends on where you live. You can get single phase to your house or a three phase connection. You don't have to worry about balancing. Just use it as three single phases. Don't short circuit them.

One reason for getting three phase to home is that the first number of units is cheaper on all three phases, in some countries.

Answer 2

Lots of misinformation in the other answers. I'm a little surprised the electrician wasn't quite right.

Houses use single phase 240/120 Volts, which comes from the secondary of a transformer in the utility. The primary is connected either phase to phase, or more commonly phase to neutral, on the 13kV (typically) 3-phase utility distribution. Everything in the power transmission is 3 phase. When a customer is too large for single phase, or requests it, they can have 3 phase service. The most basic is 208/120 volts. The 208V is between phases and 120V is phase to neutral. An apartment building may get this, even though there is no 3 phase equipment. Single phase loads can be connected phase to phase for 208 and phase to neutral for 120V.

To supply lighting loads from 3 phase, it is done like any other single phase load on a 3 phase system--connected either between 2 phases or more commonly between 1 phase and neutral. Commercial installations very commonly use a multiwire branch circuit that has 3 phases and a neutral (4 wires) going to an area of lights, with each light connected between one phase and neutral. Larger buildings will get 480/277V from the utility, use a transformer to get 120V and connect lighting at 277V.

Why did someone give a thumbs down on the question? It is a perfectly valid question.

Answer 3

well yes and no. Typical single family homes use single phase, with two hot legs and a neutral to complete the pathway for the electrons. Each hotleg is 110 volts to ground (or neutral). Everything in your home except the electric range, clothes drier, airconditioning uses one hot leg and the neutral wires only. The range, drier and a/c use two hot legs and the neutral. Normally the voltage reading between the hot legs would be 220 volts.

However, their is a second configuration for electrical service to some residences. In multi-unit complexes, the voltage can be 120 to ground for the individual hot legs, but 208 volts between two hot legs. The power company delivers three hot legs to the property. This is a more economical way to provide power (cost of installation, size of service wire, etc). However since the voltage supplied to heating units is only 208 volts, special appliances are required, which surprise, will cost the consumer more when they purchase the appliance.

The 120/240 power supplied to homes is simply the two legs of a three phase electrical system called "delta". The third hot leg is rated 208 volts to ground, and so is useless except in industrial situations with heavy machinery.

The 120/208 power supplied to homes is two legs of a three phase electrical system called "wye". Each of the three hot legs are rated 120 volts to ground, but 208 volts when measured against each other. So all three wires can be used in residential applications. Here's how it's done:
You use two of the hot legs (plus the neutral wire) in each residence, let's say "a" and "b". For the second unit you use wires "b" and "c"; and for unit three you use wires "c" and "a". In this scheme, the installation costs are substantial, both to the building owner and to the utility company.

Answer 4

The electric power coming into your house is single phase. You have one 220 volt phase that is center-tapped to provide 110 volts. The 220 volts is used for bigger loads like dryers, stoves, water heaters and space heating. The 110 volts is used for lights and other common household equipment, mixers, drills, hair dryers, toasters, etc.

Answer 5

Single phase is used for houses, you have 2 legs of 110 comming to your house. 3 phase is not used for lighting, its used for electric motors and large heaters.

Answer 6

single phase except for high load appliances where 3 phase is more efficent. to light with 3 phase use only one leg