EICR failed due to mixed MCB or RCD brands?

Consumer units are assembled as a system. The enclosure, the busbar and the protective devices are meant to be used together in the way the manufacturer describes. A second brand can be suitable, unsuitable, or simply unconfirmed. The report should say which of those the inspector found.

A plastic enclosure, a missing blank, or a device that does not fit the busbar are separate observations. Do not fold them into the word brand.

• Whether the manufacturer of the enclosure permits that device.
• Whether the device clips to the busbar and is rated for the assembly.
• Whether the connections, blanks and cover are in a safe condition.
• Whether any instruction, label or declaration shows the assembly was an approved combination.

If the device is loose, overheating, or leaving live parts accessible, the code describes that danger. If the only point is that the brands differ and no incompatibility was found, the observation may be an improvement note or a request for the manufacturer's evidence. Those are not the same finding.

Under the current A4:2026 format, an FI observation is advisory and does not by itself make the overall assessment unsatisfactory. Asking for the manufacturer's compatibility note is not the same thing as a C2.

Ask which device, which circuit, and what the inspector says is incompatible. Replacing a whole board because two logos are visible can be unnecessary. Leaving a device that the manufacturer excludes can be the actual defect.

Send the report with any photograph of the board. Remedial work is quoted from those observations, not from the brand names alone.