- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 25 Apr 2019
Mains (electricity, water and gas)
This is the AC electrical power supply that is delivered to homes and businesses and which powers electrical equipment. In the UK, this is nominally 230V at a frequency of 50Hz (typically 120V and 60Hz in the US).
Typical uses for mains electricity include:
- Space heating
- Water heating
- Air conditioning
- Televisions, computers and so on
- Washing machines and dishwashers
For more information see: Electrical supply
‘Water main’ is used in the UK to refer to a main water pipe that is part of the public water supply system; it may run beneath roads, fields and other land to supply households, businesses and light industry. The water in or from a water main is frequently referred to as ‘mains water’.
In residential applications, a sink, bath or shower may be supplied directly by mains water or indirectly via a cold-water tank and hot-water cylinder. However, regulations dictate that a kitchen sink must always be connected to the water main to allow access to clean drinking water.
For more information see: Mains water.
Mains gas is the natural gas that is distributed to buildings through a pipeline infrastructure. In the UK, mains gas is supplied to more than 21 million homes and is the most popular fuel for heating and cooking.
While the gas itself is owned by individual gas suppliers, all gas passes through the National Grid’s transmission system on its route to end users. As the owner and operator of the UK’s gas transmission infrastructure, the National Grid works with gas suppliers to ensure delivery.
For more information see: Mains gas.
 Related articles on Designing Buildings Wiki
Featured articles and news
Delivering an infrastructure revolution.
The admissibility of evidence.
How many can you name? 37 anyone?
CIOB respond to the points-based system.
When is the weather considered 'exceptionally adverse'?
ECA backs call for a rolling programme of rail electrification.
What does 'curtilage' mean and why does it matter?
Our duty to prevent harm and protect each other.
A quality perspective.
If buildings were people, they would be just starting to walk on two legs.
Air filtration and clean air standards.