Two for one: Proteus Industrial’s new range of 4 pole, 3 module RCBOs and MCBs

Two for one: Proteus Industrial’s new range of 4 pole, 3 module RCBOs and MCBs

Following the launch of its new range of 4 pole, 3 module RCBOs and MCBs, we put the burning questions to the technical team at Proteus Industrial.

The introduction of a new portfolio of 4 pole, 3 module RCBOs and MCBs which fit the existing busbar system means that electrical professionals now have access to a unique set of devices that can switch 3 phases and neutral.

The 10kA, Type A RCBO will save considerable space, time and money when installing on-site or when designing custom built boards. Gone are the days of having to accommodate additional enclosures fitted with 4 pole RCDs where these had to be cabled from a 3 pole MCB and the neutral bar in the adjacent MCB board. Now you can simply install the Proteus 4 pole RCBOs, without having to do all the extra cabling.

The RCBO combines overload, short circuit and earth leakage protection all in one compact device. The neutral pole is a switched pole, designed to ‘make first and break last’, ensuring neutral is established before phase poles close.

It can be used in any application that a traditional MCB/RCD combination would be used, but without the additional work of installing two separate devices. This is particularly useful in EV installations where a Type A MCB/RCD combination is required. The RCBO is not bi-directional so should not be used in reverse applications where the supply enters through them, i.e. input from solar panels, V to G (vehicle to grid), etc.

With installers likely to have some questions about this exciting new range, we’ve compiled a list of the common queries that the team at Proteus Industrial have been facing:

Q. As it is three modules wide, will it fit the 3 phase Proteus range MCB board busbar?

Yes, it will occupy 1 triple pole space within the Proteus MCB board busbar.

Q. If it is 4 pole but fitted to a triple pole space, how does the neutral connect?

The neutral comes with a ‘flying’ lead that terminates to the distribution board neutral block.

Q. Is this available as both RCBO and MCB?


Q. Where do the load cables connect?

All cables connect directly to the RCBO or MCB, including the neutral cable.

Q. Is this a switched neutral?

Yes, these devices have a switched neutral, so all 4 poles are switched.

Q. Is this a 30mA RCBO?

The RCBO is available with trip values of 30mA, 100mA and 300mA.

Q. What ‘Type’ of RCBO is this?

The RCBO is a Type A.

Q. Can it be used on a 3 phase supply without a neutral?

Yes it can. Neutral is not required, but you should terminate the blue neutral lead in a terminal block.

Q. What is the MCB characteristic of these devices?

Both the RCBO and MCB are C curve, available from 6A to 63A.

Q. Which Proteus MCB boards will it fit?

It will fit all Proteus boards that utilise the BX comb busbar, so will be appropriate for the following ranges: BX, XL, ABX MCB boards, OPBX O-PEN boards, CBX and MCX combined frame boards and busbars fitted to custom built boards. Put simply, it will fit most boards built over the last 30 years.

Q. What BS EN standard does this comply with?

It complies with BS EN 61009-1 and BS EN 61009-2-2.

Get more details about this new range of circuit protection devices from Proteus Industrial here

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