Short answer: a single-line diagram (SLD) is a simplified schematic showing the whole electrical distribution in one view: supply incomer, metering, main switch, distribution boards, sub-mains and final circuits, with protective devices and ratings. It is the fastest way to understand any installation with more than one board.
What the service involves
We produce clean schematic SLDs for drawings for Manchester projects of all sizes: incomer and metering arrangements, main and sub-distribution boards, sub-main cabling references, final circuit schedules, protective device types and ratings, and RCD/RCBO protection notes. Drawn with standard symbols to BS 7671:2018+A4:2026, delivered as PDF with DWG available.
When a single-line diagram is needed
- Small commercial premises — shops, offices, cafés and hospitality units with distribution across floors
- HMOs and multi-dwelling buildings — landlord supplies, communal areas and flat distributions in one view
- Plant and meter rooms — documenting incomers, metering and sub-mains for maintenance access
- After alterations — boards added over the years with no drawing ever updated
- For your electrician — the quickest briefing document for anyone new to the installation
SLDs pair with schedules
A single-line diagram shows the structure; a consumer unit schedule lists the detail of each board. Together with as-fitted layouts, they form a complete record set — the package commercial handover and O&M manuals expect.
From existing installations
No design drawings? No problem. Your electrician's test and inspection data, clear board photographs and a description of how the distribution is arranged are usually enough for us to produce an accurate schematic. Trade clients regularly send this package for handover documentation.
Pricing considerations
SLDs are scoped by the number of distribution boards and circuits — a two-board HMO is a different job from a three-floor office. Send what you have and we will confirm a fixed price; see how pricing works.
Single-line diagram questions
What is a single-line diagram?
A simplified schematic that shows the whole electrical distribution in one view: supply incomer, metering, main switch, distribution boards, sub-mains and final circuits — with protective devices and ratings. One line represents each circuit, hence the name.
When is a single-line diagram needed?
Typically for small commercial premises, HMOs and multi-dwelling buildings, plant rooms, and any installation with more than one distribution board. They are also the quickest way for an electrician to understand an unfamiliar installation.
Can you produce one from my existing installation?
Yes. Your electrician's test data, board photos and a description of the distribution arrangement are usually enough. We draw it up as a clean schematic with a matching consumer unit schedule if required.
Related services
- Consumer unit schedules — the circuit-by-circuit detail
- As-fitted drawings — record the physical installation