Outside fused spur to garage. Fused removed but tripping consumer unit

[x60rsa]

Hi

I need to changed the socket in my garage as its cracked. It's fed from a house socket which is fused externally. From the fused box it goes to an armoured cable to the garage.

The fuse is removed, does this mean that there should be no power now to the garage?

 

[Murdochcat]

That fuse only isolates the live so you still have continuity on the neutral AND the CPC, hence why the rcd will still trip

And yes without the fuse the power should be off

 

[x60rsa]

OK so to isolate this fully and change the socket I need to isolate at the consumer unit?

Thanks

 

[Harry Bloomfield]

Change the fuse unit, to a double pole, for next time, then it will and can be fully isolated.

 

[plugwash]

Fuses, MCBs and many RCBOs will only isolate the line (aka live) conductor. Standalone RCDs and consumer unit main switches will generally isolate both the live and neutral. So will some newer RCBOs.

Isolating just the line and leaving the neutral connected is acceptable under BS7671 if it's a TN supply and you can assume the neutral is solidly connected to earth by the supplier. Not a problem on TN-C-S, more questionable on TN-S but probablly ok. On a TT system you are supposed to isolate the neutral before working though I bet in practice many people dont.

As has been said, if you isolate just the neutral downstream of a RCD and then touch the neutral and earth conductors together you are likely to trip said RCD. Been there, done that.

Even after isolating it's good practice to keep your contact with circuit conductors to a minimum and if you must touch a conductor to test for dead immediately before touching it.

 

[Harry Bloomfield]

many RCBOs will only isolate the line (aka live) conductor.

I wasn't aware of that.