Is this safe?

[Iknownartheeng]

I've recently moved into a house and had all the electrics checked (can't remember what the actual compliance certificate was called).

The electrician said the system passed but, although not dangerous, the additions & alterations the previous owner made were 'interesting'.

There was a single socket in an outside building that I changed to a double RCD socket.

When I try and use a small fan heater off this socket it trips the fuse in the main old-style fusebox. The fuse that trips has an 8 amp rating and is the circuit for the upstairs lights.

If I changed this fuse to 16 amps, would it be safe?

Thanks

 

[johnny_t]

This is my first impression, but you may get someone who can give a more expert view on the regs later.

Current drawn is equal to the power rating of a device divided by a supply voltage, so anything above 1.9 kW would blow an 8A fuse on a 240V supply.

However, IIRC, any spur for sockets off the lighting circuit should not be able to draw more than 5A (might even be 3A) and should be fuse-protected accordingly (and ideally special round-pin plugs to stop anyone plugging a heater in). 8A is too high, 16A is much too high, and you should either come off the sockets ring or have a dedicated circuit if you want to plug a heater in.

 

[slippyr4]

If I changed this fuse to 16 amps, would it be safe?

Almost certainly not. The fuse is an overcurrent protection device. If you put a 16A fuse in there, then any fault on your lighting circuit would need to draw 16+ Amps before the supply was disconnected. Therefore, for this to be safe, every joint, junction box, ceiling rose, switch etc on the lighting circuit (and cable too) would need to be capable of carrying 16 amps without catching fire. It almost certainly is not.

I would recommend you disconnect your socket, and find a way to connect it more appropriately. Can you spur off an existing (13A) socket from a ring? extend a radial? put a new radial in to the outside building?

 

[Iknownartheeng]

Thanks for the replies. Thought as much but thought I'd check. Why is the easy option always wrong???

Now I need to try and find where he buried and connected the cable...

 

[ban-all-sheds]

If the cable is buried, and is not either SWA or in proper underground conduit with watertight joins, don't re-use it.