New and upgraded three-phase supplies
Assessing what the site has, what it needs, and the works required within the customer's electrical installation to accept a larger supply.
Three-Phase Power
Three-Phase Electrical Installation and Supply Capacity Upgrades
Three-phase power is commonly used at commercial and industrial sites where electrical demand exceeds the practical capacity of a single-phase supply. It can provide greater electrical capacity and is commonly used for equipment such as machinery, large air-conditioning plant, commercial catering equipment, lifts, compressors and higher-powered EV charging installations.
Projects in this area are usually about capacity: either a site has three-phase and needs it distributed further, or it does not and needs to find out what is involved in getting it. GridGuys is a matching platform, so we pass those enquiries to contractors who work on supply and distribution projects.
Scope
What three-phase work involves
Three-phase projects tend to sit somewhere between the incoming supply and the equipment it feeds.
Main and sub-main distribution
Three-phase distribution boards, sub-mains to remote areas, mezzanines and outbuildings, and correctly rated protection throughout.
Load assessment and balancing
Reviewing existing demand, spreading loads evenly across the three phases and identifying where an unbalanced installation is causing problems.
Three-phase equipment connections
Final connections and isolators for machinery, chillers, compressors, ovens, lifts, pumps and other three-phase plant.
Switchgear and metering arrangements
Main switch panels, isolation arrangements, sub-metering and space planning for future circuits.
Preparing for future load
Capacity headroom for electrification projects such as EV charging, heat pumps or additional production equipment.
Practicalities
Common three-phase project requirements
These are the points that most often shape the programme, the method and the price on this type of project.
- 01
Knowing your existing supply
The current supply rating, main fuse size and whether the incomer is single or three-phase are the first questions. A photo of the intake position usually answers most of them.
- 02
Distribution network operator involvement
Where the incoming supply itself has to change, the works involve the regional distribution network operator as well as the electrical contractor. Their process and charges sit outside the contractor's own quotation.
- 03
Realistic load figures
Equipment nameplate ratings, or a list of what will run at the same time, allow a contractor to size cables and protection properly rather than guessing.
- 04
Route and access
Cable routes across a site — through ceilings, across yards or underground — often drive the cost more than the board work at either end.
Where it applies
Where three-phase installations are needed
Any site adding significant load is a candidate; these are common examples.
- Factories and production facilities
- Warehouses and distribution centres
- Commercial kitchens and food service
- Workshops, garages and MOT bays
- Fleet depots adding EV charging
- Gyms, leisure centres and swimming pools
- Farms and rural business units
- Offices with large mechanical plant
Related work
Related electrical requirements
A capacity project usually touches several other areas of the installation.
Industrial electricians
Machinery, control panels and process power that a three-phase supply exists to serve.
Factory electricians
Production-floor distribution and new line supplies fed from upgraded three-phase capacity.
Warehouse electricians
Large-floorplate distribution, high-bay lighting and racking power across storage buildings.
Commercial EICR and testing
Condition reporting on the existing installation before deciding what can safely be extended.
Useful information when requesting a three-phase quote
You do not need all of this to submit an enquiry, but the more you can include, the more accurately a contractor can respond.
- Whether the site already has a three-phase supply
- Existing main fuse rating or supply capacity, if known
- A photograph of the intake and main switch position
- The equipment or load you need to add, with ratings
- Where in the building or site the new supply is needed
- Approximate cable route distance from the intake
- Any planned future load such as EV charging
- Whether a supply interruption can be arranged
How GridGuys works
A lead-generation and contractor-matching service
GridGuys does not carry out electrical work. We take your enquiry, review what is needed and introduce you to an electrical contractor working in that category. From the introduction onwards, the contractor deals with you directly.
- 01
Describe the project
Give the site details, the works required and anything you already have such as drawings or photos.
- 02
We review the enquiry
We look at the scope, location and timeframe so the enquiry goes to a contractor set up for that work.
- 03
You are introduced
We connect you with an electrical contractor whose capabilities match what you have described.
- 04
You receive a quotation
The contractor prices the works and deals with you directly from that point onwards.
FAQs
Three-phase power questions
Request a three-phase installation quote
Tell us what you need to power and what supply the site has today. A photo of the intake position and equipment ratings help a contractor respond accurately.