Walk up to a distribution board in almost any building more than a few years old and look at the chart on the inside of the door. There is a reasonable chance it is handwritten, partly illegible, and describes an installation that has changed several times since it was written.
Ways have been reassigned. Circuits have been added during a refurbishment and never recorded. A board has been re-fed from somewhere else entirely. Someone has crossed out three entries in biro and written new ones in the margin. Nobody knows with any confidence what Way 14 actually feeds.
This matters more than it looks, because the documentation is not optional.
Before you read on
This guide is general information about electrical record documentation. It is not electrical design advice and it is not a substitute for professional judgement. The requirements that apply to your specific installation should be confirmed with a qualified electrician or competent person.
Outsource CAD provides drawing and documentation services. We do not carry out electrical design, inspection or testing.
What BS 7671 requires
BS 7671, the IET Wiring Regulations, requires that a diagram, chart, table or equivalent form of information is provided for every electrical installation. It should identify the circuits, the type and composition of each circuit, the method used for fault protection, and the characteristics of the protective devices — enough information for someone to understand and safely work on the installation without tracing circuits from scratch.
In practice this is the distribution board schedule, sometimes called the circuit chart or circuit schedule. It is the document that says DB2 Way 7 is a 32A Type B MCB feeding the second floor small power ring, in 2.5mm twin and earth, with RCD protection on that way.
The requirement applies to the installation as it stands, not only to new work. An installation that has been modified should have documentation reflecting the modified state.
What a compliant schedule contains
A schedule that satisfies the requirement typically covers, for each way on the board: the way or circuit number, the circuit designation in plain language, the protective device type and rating, RCD or RCBO details where applicable, cable type and size, the reference or installation method, and the number of points served where relevant.
Alongside the per-circuit information, the schedule identifies the board itself — its reference, location, supply origin, and what feeds it. That last point is what turns a set of individual board schedules into a usable record. Knowing that DB2 is fed from DB1 Way 3, which is fed from the main LV panel, is what allows someone to trace a fault or isolate safely.
Why existing buildings so rarely have accurate records
The pattern is consistent across sectors, and it is a documentation failure rather than an electrical one.
Modifications are not recorded
A tenant fit-out adds circuits. A plant replacement changes a supply. A department moves and the small power is reconfigured. Each change is carried out by a competent electrician and is electrically sound — but the board chart is not updated, or is updated by hand on the one copy inside the door, which is then superseded by the next change.
The record exists but not in a usable form
Sometimes the information exists in test certificates, commissioning records, or a contractor's file. It is simply not consolidated into a schedule anyone can use. An estates team holding forty inspection certificates does not have a drawing record.
The original documentation was never issued
On older installations, or on projects that closed out badly, schedules were never produced properly in the first place. Whatever was on the board at handover is all there has ever been.
Where the gap surfaces
During inspection and testing
An inspector carrying out a periodic inspection needs to understand the installation to test it properly. Where documentation does not reflect the installed condition, the inspection takes longer, coverage may be limited, and observations are likely to be raised about the adequacy of the records themselves.
During a fault or emergency
Someone needs to isolate a circuit quickly and the chart is wrong. This is the scenario the requirement exists to prevent.
During modification or refurbishment design
A designer working on an alteration needs to know existing loads, spare ways and supply arrangements. Where the record is unreliable, the design starts from a survey that should not have been necessary, and the cost of that survey lands on the project.
At portfolio level
Organisations with large estates — local authorities, housing providers, NHS trusts, schools, universities, industrial operators — carry this problem across dozens or hundreds of buildings simultaneously. The individual gap is small. The aggregate is a significant operational and compliance exposure.
Rebuilding electrical records for an existing building
Reconstructing accurate schedules for an existing installation is a documentation exercise, and it works from whatever evidence exists.
The usual inputs are photographs of each board and its existing chart, the electrician's test results and schedules of test results, any existing drawings or record documentation however out of date, and a site survey where the record is genuinely absent.
From that material a complete, legible, consistent set of distribution board schedules can be produced, along with a distribution diagram showing how the boards relate to one another and back to the origin of the installation. The output is CAD and PDF, formatted consistently across every board in the estate rather than in whatever format each original contractor happened to use.
An important boundary
This is documentation work, not design work.
Outsource CAD produces drawings and schedules from information supplied by your electrician, engineer or inspector. We do not design electrical installations, size cables, select protective devices, or determine circuit arrangements. Those are decisions for a competent person under BS 7671, and they stay with your electrical engineer or contractor.
What we remove is the drawing production burden — the hours spent turning a folder of test sheets and board photographs into a consistent, legible, issued record set. That is usually the part an M&E contractor or estates team has least capacity for and least appetite to do.
How Outsource CAD can help
We produce distribution board schedules, circuit charts, cable schedules, panel layout drawings, single line diagrams and distribution diagrams for UK commercial, industrial, public sector and residential installations.
Send us photographs of the boards, your test results, and any existing drawings, and we will produce a complete schedule set in AutoCAD DWG with PDF copies. For estates work we apply a consistent format across every building so the whole portfolio reads the same way.
Call +44 28 9009 8876 or email info@outsourcecad.com.
Frequently asked questions
What is a distribution board schedule?
A distribution board schedule records what every circuit on a board feeds, along with the protective device type and rating, cable size, and protection arrangements. It is sometimes called a circuit chart or circuit schedule. BS 7671 requires this information to be available for the installation.
Can you produce schedules for an existing building with no records?
Yes, provided there is evidence to work from. That usually means board photographs and the electrician's test results. Where there is genuinely no information available, a site survey by a competent electrician is needed first — we produce the documentation from what that survey records.
Do you design the electrical installation?
No. We are a documentation service. Circuit design, cable sizing and device selection are carried out by your electrical engineer or contractor as the competent person. We turn their information into accurate, consistent, issued drawings and schedules.
What do you need from us to get started?
Photographs of each distribution board and its existing chart, the schedule of test results or inspection documentation, and any existing drawings even if out of date. If a board is unrecorded, we will tell you what additional information is needed rather than assume.
Can you work across a whole estate rather than one building?
Yes. For portfolio work we apply a single consistent format across every building and board, so the records read the same way regardless of who originally installed them. Progress is tracked on a shared online register.
