RCBOs

For the Trade

Start with the space you’ve got in the board and how the circuit will be used. That usually narrows RCBOs faster than anything else. A cramped layout can rule out a larger body or awkward terminal arrangement. The wrong pole count causes trouble later if the circuit needs a different switching arrangement. After that, check the trip characteristic and breaking capacity against the job, not just the label on the front. Most of the swaps I see come from matching the device to the board size, then finding it doesn’t suit the actual circuit once the work’s underway.

Popular RCBO Formats

A single pole RCBO suits the common domestic setup where you want one circuit isolated cleanly. A double pole RCBO, or 2 pole RCBO, fits circuits that need both conductors switched together.

Type A RCBOs are the usual pick on modern loads with electronics. Type AC still appears on simpler circuits, but it is less often the first choice now.

If you are weighing an RCBO breaker against a combined RCD MCB or RCD MCB combo, the RCBO keeps one fault from taking out the rest of the board. That gives you tighter selectivity and less disruption on the board. Power Distribution & Circuit Protection

Key Differences When Choosing

What usually decides it is the circuit and the board, not the label on the front. For simple circuits, a single pole rcbo is often enough. If you need both conductors switched, a 2 pole rcbo or double pole rcbo is the usual call. It takes more space and usually costs more.

Type A rcbo is the better fit where the load is less predictable. Type AC still turns up on simpler legacy jobs. If you are building out a board, check the layout against Consumer Units. If the circuit is being controlled rather than just protected, you may need Contactors instead.

Next Decisions After Choosing

Once you’ve picked the RCBOs, the next call is what still needs to sit in the board and what has to be finished off on site.

A tidy board build usually comes down to the right consumer units and the right consumer unit accessories. A cramped enclosure or a missing blanking piece slows the job later. If the install needs more control gear, contactors are the next stop. If it’s only the final board-out, keep the layout simple and use the parts that suit how the circuit is being split.