Cooker ring main disconnected - still getting voltage?

strawberrylane

I am in the process of swapping over my built-in oven. I have removed the 30A fuse for the cooker ring main at the fuse board in the garage, switched the cooker control switch off in the kitchen and disconnected the old cooker. I have not connected the new cooker yet.

However, I have noticed that if I switch the cooker control switch on (with nothing connected to the bare wires to the cooker), there is a residual voltage across the L and N wires of approximately 6V (a.c.). This reading is taken with the 30A fuse for the cooker ring main removed. I was expecting there to be zero volts (for information, with the 30A fuse in place the voltage is 224V a.c.)

Why is there such a residual voltage? Is this normal or does it suggest a problem somewhere with the wiring? On further investigation, I noticed that the residual volatge drops progessively as I unplug or switch off other electrical items in the house. It is at zero only when everything else is off/unplugged. Is this something I should be worried about? Any feedback or comments gratefully received. Thanks.

YorkshireBoy

In a word......Inductance.

The cable runs with other (live) cables and voltage is "induced" into it.

If you were using a lower impedance meter, the meter itself would "discharge" the circuit and so it would register a zero reading.

Mr_Proctalgia

Have to agree with YB - Modern meters can be sometimes too sensitive, you have an induced voltage - if in doubt try to put a 6V bulb across the Ph & N wires, or use something like an AVO 7 or 8 to measure - There will be nothing there!