Standard explained
Distribution Boards and Consumer Units Explained
Distribution boards (and domestic consumer units) house the protective devices that control and protect each circuit — their condition is central to any EICR.
A distribution board — called a consumer unit in a dwelling — houses the protective devices (fuses, MCBs, RCDs, RCBOs) that control and protect each circuit. It is the hub of the installation and one of the most closely examined items on an EICR.
What inspectors look at
- The type and condition of protective devices, and whether they are correctly rated.
- Adequate RCD protection for the circuits that require it.
- The enclosure — for dwellings, a non-combustible (typically metal) enclosure is now expected.
- Correct labelling and safe isolation arrangements.
Common reasons to upgrade
- No or inadequate RCD protection.
- Obsolete boards (for example old rewireable fuses) or damaged components.
- A combustible enclosure in a dwelling where a metal one is now expected.
- No space for required devices such as RCBOs, SPDs or AFDDs.
On an EICR
Board issues range from C3 (improvement) to C1/C2 where danger or inadequate protection is involved. Upgrading the board is often the single most effective way to bring an older installation up to current standards — see consumer unit / board upgrades.
Frequently asked questions
When should a consumer unit be upgraded?
Consider upgrading when the board lacks adequate RCD protection, uses obsolete or damaged devices, is a combustible (non-metallic) enclosure where a metal one is now expected for dwellings, or cannot accommodate required protective devices such as RCBOs, SPDs or AFDDs.
Related service
Distribution Board Upgrades
Upgrade of distribution boards in commercial and multi-occupancy installations.
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Learn moreThis article provides general guidance and distinguishes legislation, British Standards and good practice. It is not legal advice. Always confirm the specific duties applying to your property and tenure.