Now on its knees ;-)
Just starting to move the kitchen spur, with the fuse out of the fuse box.
The whole house RCOCB tripped!
Put my meter on the wires, and Neutral and Earth seem the same, but there is about 3V between the live and Neutral/Earth.
How worried should I be?
Is this likely to be induced current from loads of parallel wires, or potetially something more serious?
The house was checked over by an electrician before the Combi boiler was wired in.
TIA
Dave R
Caused by you shorting the neutral and earth together (or live and earth if there's a load still connected to the circuit, which is connecting live to neutral).
Not worried -- it's normal.
If you short the neutral to earth, some of the current returning in the neutral from other circuits will be diverted to earth, causing an imbalance at the RCD, so it will trip.
You probably touched N and E... You need to isolate *both* L and N at the fuse box for the circuit to be considered "isolated" and safe to work on.
Owain
Thanks - I have now wrapped the bare ends in tape.
I hadn't realised that you could trip with the fuse out.
The message from "David W.E. Roberts" contains these words:
The fuse (or MCB if that is what you have) just isolates the live side of the circuit it serves. If you have equipment in use on other circuits shorting the neutral to earth on the circuit you are working on will allow some current to bypass neutral side of the RCD and the imbalance will cause it to trip. BTDTGTTS.
Nanny will be along in a minute to tell you you *must never* work on individual circuits without isolating the whole supply at CU main switch. :-)
No need to be surprised - it looks for an imbalance between the current flow on line and neutral, so if you short neutral to earth it'll trip regardless of the fuse or whatever being removed.
On Sat, 04 Aug 2007 18:34:23 +0100, "Dave Plowman (News)" mused:
*Can* trip, they don't always. Depends on the difference in potential between N + E.
I was going to say that, a N E short doesn't cause an RCB trip here but then the E is bonded to the N and into the real ground at the pole outside...
Yes - I suppose there's less likelihood on a PME installation. But I doubt the OP has this with a fusebox.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "David W.E. Roberts" saying something like:
That's offal. Still, I'm sure you'll get to the guts of the matter.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.