MCB, RCCB and RCBO are easy to confuse in a quotation because their names and appearance can be similar. Their protection functions are different. For a distributor or panel buyer, identifying the required function comes before comparing the price, width or current rating of a proposed device.
This guide explains the three categories and the information to check when comparing offers. The final device specification should follow the project design, the exact manufacturer’s documentation and the requirements of the destination market.
Compare the protection functions
| Device | Overload and short-circuit protection | Residual-current protection |
|---|---|---|
| MCB | Yes | No integral function |
| RCCB | No integral function | Yes |
| RCBO | Yes | Yes |
An MCB is a miniature circuit breaker. An RCCB is a residual-current circuit breaker without integral overcurrent protection. An RCBO combines residual-current and overcurrent protection. Schneider Electric explains the RCCB and RCBO categories and the MCB and RCBO functions in its manufacturer guidance.
Why the difference matters in a quotation
A quotation headed only “circuit breaker” leaves an important question unanswered: which protection functions are included? An offer for an RCCB and an offer for an RCBO describe different categories, even when some of their visible ratings match.
Ask the supplier to identify the device category beside each model reference. If a proposed alternative changes that category, treat it as a design change requiring review. A similar front label or enclosure size is insufficient evidence that the two offers are equivalent.
Keep current ratings and residual sensitivity separate
For an RCCB or RCBO, record the rated current and rated residual operating current in separate comparison fields. Copy their values and units directly from the proposed model’s datasheet. A current rating printed on an RCCB does not establish that it contains overload protection; the category distinction above remains essential.
Residual-current coordination also needs more than a matching sensitivity value. ABB’s technical explanation of residual-current selectivity discusses the relationship between device thresholds and operating times. Have the project designer assess the required combination rather than accepting “same amperage” as confirmation of compatibility.
Compare the exact models, then the commercial offer
Once the required category is clear, compare documents for the actual offered models. Useful fields include the rated voltage and frequency, pole arrangement, current ratings, applicable breaking-capacity information, residual-current characteristics where relevant, dimensions and terminal arrangement. Ask which document and revision support each entry.
Keep unresolved fields visible. A blank cell should remain a question for the supplier instead of being filled with a value from another model in the same series. If the application requires evidence of conformity, request documents identifying the exact model and check their scope against the project requirements.
Check proposed substitutions carefully
A replacement proposal should identify the original reference, the offered reference and every relevant difference. Ask whether accessories, panel space or the protection arrangement need separate review. This makes it easier for the technical reviewer to approve or reject the alternative before an order is placed.
Compare prices and quantities only after the specification is agreed. A lower line-item price has limited meaning if one offer includes a different set of protection functions or leaves essential technical information unconfirmed.
Explore the relevant Soltree product pages
Browse the SLA series AC miniature circuit breakers and the SLRC series residual-current circuit breakers to find references for your enquiry. A product-family listing is a starting point; ask for the selected model’s documentation to confirm its specification.
Use Contact Soltree to share the required protection category, model references, quantities and destination. Include the project specification and any proposed alternative so the enquiry can be discussed against the same requirements.
