Whole CU is RCBOs since 6 months. Fine, no issues
So, I put in a new wall light, one 25W incandescent bulb, connect to the RCBO for that room, switch on, the bulb lights for a nano-second then the RCBO trips.
Oh, think I. The cable to the switch might have a screw through it. So I bypass the switch, wire straight to the fitting - I can do that as there's a JB for the fitting a few feet away in the CU cupboard.
Nope, still trips.
Try another bulb. Same.
So now I try both bulbs in another fitting on the same RCBO in the same room, both OK.
So, perhaps the bulbholder in the light fitting is bad. So I connect another bulbholder to the JB on a bit of cable, disconnect the wall light. Still trips.
Now I take the feed from the CU out of the JB, connect the bulbholder straight to the feed.
Still trips.
Remove the bulb, it doesn't trip, so it's not the cable.
Arrrgh.
So now I connect a brand new bit of cable, couple of foot, to the out of the RCBO and the N buss, no earth this time, hang the bulbholder on the end and it still trips!!!
Connect to another RCBO on another lighting circuit, same.
Disconnect the existing L from the RCBO so there's only my new bit of cable and bulbholder and bulb, and it still trips.
WTF is going on, in the forty-five years I've been connecting things to the electrikery the power has always flowed from the L through the load back to the N, simple, am I going mad?
So, I put in a new wall light, one 25W incandescent bulb, connect to the RCBO for that room, switch on, the bulb lights for a nano-second then the RCBO trips.
Oh, think I. The cable to the switch might have a screw through it. So I bypass the switch, wire straight to the fitting - I can do that as there's a JB for the fitting a few feet away in the CU cupboard.
Nope, still trips.
Try another bulb. Same.
So now I try both bulbs in another fitting on the same RCBO in the same room, both OK.
So, perhaps the bulbholder in the light fitting is bad. So I connect another bulbholder to the JB on a bit of cable, disconnect the wall light. Still trips.
Now I take the feed from the CU out of the JB, connect the bulbholder straight to the feed.
Still trips.
Remove the bulb, it doesn't trip, so it's not the cable.
Arrrgh.
So now I connect a brand new bit of cable, couple of foot, to the out of the RCBO and the N buss, no earth this time, hang the bulbholder on the end and it still trips!!!
Connect to another RCBO on another lighting circuit, same.
Disconnect the existing L from the RCBO so there's only my new bit of cable and bulbholder and bulb, and it still trips.
WTF is going on, in the forty-five years I've been connecting things to the electrikery the power has always flowed from the L through the load back to the N, simple, am I going mad?
