Switches in other bedrooms turning on different lights after I put new light up

I recently put up a light in my bedroom but the switches in other rooms now turn on different lights, there are 9 wires altogether coming through the ceiling, 3 earth which are connected together, 3 red (live) which are together, 2 neutral which are together connected to the neutral on the light and a switch live which is connected with the live on to my new light. I have searched and Googled everything and nothing has worked. Please help.

• Sounds like you must have undone some of those bundles and then reconnected the wrong wires. Does that sound like a possibility? Mar 19, 2019 at 19:45
• Jphi1618 make that an answer the op has the feed for the switches in the wrong place. Mar 19, 2019 at 20:13
• What are the bundles? I followed a diagram online but doesn't seem to be working Mar 19, 2019 at 20:15
• Iv added picture of what I followed Mar 19, 2019 at 20:18
• @Daniel, I say bundles because in the US we use wire nuts to hold several wires together (a bundle of wires) rather than the screw connectors you have pictured. Did you undo any wires other than the ones for the light fixture? Getting the in/out/switch wires mixed up could lead to odd behavior. Mar 19, 2019 at 20:32

Note: I'm in the US, so I apologize if I get any vocabulary wrong.

I'm going to describe the picture you posted in your question because I believe you might not know exactly what each wire is doing. I will number them left to right, 1-8 (not counting grounds/earth).

Wires 1-3: Neutrals are not switched, so they can all be tied together. Neutrals and hots should never be connected, and grounds should also be separate. Wire 1 goes to the fixture, wire 2 is coming "in" from the breaker panel and wire 3 carries on the neutral to the next box (probably another light).

Wire 4: This is the "live" wire coming in from the breaker panel. It is energizing the screw terminal block and supplying power to wire 5 and 6.

Wire 5: Gets power from wire 4 and carries it on to the next box.

Wire 6: Gets power from 4 and carries it to the switch.

Wire 7: This is colored as a neutral, but wrapped with brown tape in the diagram to show that it is doing the job of a hot wire. This is a live wire coming back from the switch. It is live when the switch is on. These two wires for the switch are known as a "switch loop" and is one of the only times (the only time?) it's acceptable for a neutral colored wire to be used as a hot.

Wire 8: Bonded to wire 7 and providing power to the lamp when the switch is on.

Now, if you confused any of the "in", "out" or "switch" wires, you could have strange results. With the hot wires disconnected from the screws and the power on, the only hot with voltage should be the IN cable. With the power off, you can check for continuity between the black and white wires of the SWITCH cable. There should be continuity with the switch on, and no connection with the switch off. The remaining cable that has no power and is not related to the switch will be the OUT cable.