What an RCD does
Residual-current protection responds to an imbalance in current. Equipment commonly described as an RCD can have different forms and applications. A customer does not need to identify the exact device type before explaining a trip or requesting an assessment.
“The RCD has gone” is often a description of a loss of power rather than a confirmed failed device. Describe what stopped working and what you observed. The electrician can identify the protective arrangement from the installation and testing.
How an RCBO differs from an RCCB
How an RCBO differs from an RCCB
An RCBO includes residual-current and overcurrent protection in one device for a circuit. An RCCB provides the residual-current function and needs the installation’s overcurrent protection to be addressed separately.
Individual circuit arrangements can change how faults affect other parts of the installation, but fitting a particular device is not a universal cure for nuisance trips. A fault still needs diagnosis, and equipment selection must suit the circuit and board.
Why device compatibility matters
Why device compatibility matters
A consumer-unit proposal needs to consider the existing circuits, condition, earthing, protection and intended changes. Adding equipment to an old board or replacing the board as a whole requires more information than the device names on a shopping list.
Compatibility is not established by a device fitting physically into a space. Discuss the proposed arrangement with the electrician and provide any existing report. Do not buy protective devices or remove a cover to identify a brand before assessment.
What to compare in a consumer-unit quote
What to compare in a consumer-unit quote
If your priority is reducing the extent of a power interruption, explain which equipment and rooms are important. If a report has identified a defect, share its observations. If you are adding loads, provide the equipment requirements.
Ask the quotation to explain what will be changed, which existing issues need attention, how the circuits will be tested and what records will be provided. That is more useful than comparing quotes only by the number of RCBOs.
What to share with your enquiry
- Your reason for considering a change
- Existing inspection report if available
- Circuits or equipment affected by trips
- Planned additions to the installation
- Safe photo of the closed board, if accessible
Questions answered
Will fitting an RCBO fix a circuit that keeps tripping?
Only if a faulty or unsuitable device is the cause. An RCBO does not repair damaged wiring or faulty equipment. Repeated trips need investigation before a protective device is changed.
Ask Max about thisCan I upgrade to RCBOs without replacing the consumer unit?
That depends on the board, compatible devices, available arrangement and the condition of the existing circuits. A device fitting into a spare space is not enough to confirm suitability. The assessment should establish whether the board can be retained and what work is needed.
Ask Max about thisIs surge protection the same thing?
No. Surge protection addresses transient overvoltages. Residual-current and overcurrent devices have different functions.
Ask Max about thisIs an RCCB the same as a circuit breaker?
An RCCB provides residual-current protection but does not provide overcurrent protection by itself. An RCBO combines residual-current and overcurrent functions. The correct combination depends on the installation, so share the board details when asking about improvements rather than selecting devices by their names alone.
Ask Max about thisWhy does one RCD switch off several circuits?
Some consumer units have several circuits sharing one residual-current device, so its operation can interrupt more than one circuit. That does not identify the faulty item. An electrician can explain your arrangement and investigate recurring trips before proposing changes to how the circuits are protected.
Ask Max about thisSources and further reading
Read the original guidance relevant to this question. Building Regulations and rental-law references here relate to England.