How to Wire an RCBO

You need to be sure you have room in your box for the device. I will assume you do at this point. You will be using a device that plugs into the position where a breaker would normally go. You will have to identify the circuit you want to protect so you can remove the breaker from the box and it from the breaker.

You turn off the breaker checking to see if you have the right circuit. After you have identified you need to turn off the main breaker to the box. Then you pull the breaker from the box and disconnect the wire connected to it. There will only be one wire connected in this example as it is a twenty amp 110 volt circuit.

The main breaker should already be off so you will be working with a flashlight at this point. You need to trace the other wires in your cable. One will be bare or non existent, the other should be white. The one that was connected to the breaker should be black. The white one should be connected to the neutral bus bar. Disconnect the white and black wire and prepare the ends.

Now that the ends are clear you can connect the RCBO device. Note it has a blue or green wire at the top. It goes to the neutral bus bar. At the bottom it should be marked L out and N out . The black is the load and goes L out, the white goes on N out. The bare wire stays where it was. Note: Nowhere in the leg can the bare wire be connected to the white neutral wire or you defeat the purpose of isolating the neutral.

You can wire the device plugged into the box or wire it before you plug it in. Whichever is easier. This type of device is fed by the hot bar inside the box which will make contact with the back of the device when plugged in. You can place the device in the main breaker or at the control box for the area you are protecting.

If you place it at the end away from the main breaker box you could be using a different type unit. This one will have holes at the top and bottom marked L in N in L out N out. Your feed from the main breaker is the in and your feed to the hot tub etc. is your out. Test the black from the box and make sure it is hot. Test the neutral and make sure there is no voltage on it. CUT OFF THE POWER Then wire it up and test according to instructions.