I'm just starting to renovate my new old little house, and want to remove all the old wiring, but install just one new socket that I can use during the renovation. All the existing wiring is a mess, with some clearly not used for many years (ie the old electric panel heaters), some sockets hanging off the walls, some sockets dead, and some wired into a low rated light circuits etc. The net result is blown fuses if the 'wrong' socket is used. It's nearly all surface mount, and I want it all out before I redo the walls and kitchen. All the main fuses are badly/not marked, so I'm not sure what does what.
Up in the loft is the meter with 3 phases, and 4 wires (3 blacks, 1 something else). All these go into a box with just a main switch. Only the 3 blacks go to the switch, the other just to the box itself. Coming out of this switch box the wires then go to another box with the main 3 X 16A fuses. Below this is then the regular fuse/distribution box. This has 3 rows of fuses, and it appears that each of the 3 black wires (from the main 3 x 16A fusebox) supply a bussbar for each row of fuses, thereby splitting the 3 phases into 3 rows of single phase fuses. From these various fuses go all the mess of wires to the various 1ph circuits. I hope you're still with me! It appears that the 4th wire from the meter/main switch box/main fuse box, connects to a large earth style connector in this fuse box. I assume this is a combined neutral/earth?
So my question is (finally), where do I connect my new cable for my new socket to? I'm guessing that the live goes to one of the fuses, but where does the neutral and earth connect to? Are they joined and connected to the 'earth' stud in the fuse box which is in turn connected back through the various boxes to the 4th wire from the meter?
|
|
Ancient Swedish domestic wiring is not my strong point, but it does sound like you have 3 phases, in star configuration, with the'4th wire' indeed being earth. So connecting as you suggest should be OK; but I'd want to make sure with a multimeter first. What happens if one of the main fuses blows and unbalances the 'star' I'm not sure as it's 30 yeas since i did any 3 phase stuff.
|
Quite simple really if you are just doing one socket. Disconnect all the wires from the fuses in the distribution box, and run one wire from your socket, live to fuse and return to your single ground/neutral point.
Such a low load (single socket) does not need to be balanced across phases.
|
|
For the few quid it would cost to get a qualified sparky to disconnect everything and put in a safe power supply it it not worth risking your life. Wet floor, DIY bodge = not good.
|
Ha, well I would get a man in, but they're hard to find, unreliable, and expensive - just like tradesmen the world over it seems. If you don't hear from me again, you know I got it wrong.
I can't see how it can ever be balanced anyway. Sure, it can be wired so that if everything is switched on it will be balanced, but it never works that way. The water heater (2kw) comes on and off randomly, same with the water pump/heaters/kettle and other high load stuff. I guess that if I'm running a big load on phase one, someone else down the road will be doing the same but on 2, and so on. Over the whole of the network it may be balanced.
I've just been over there (it's next door), and he's had a fairly recent socket put in for the water heater. So I'll have a better look tomorrow at where it's been wired into the fuse box. I can then just emulate it without making my (lack of) hair stand on end.
|
|
IIRC (it is 30 years ago) with a fully balanced star configuration you don't require the return at the centre of the star at all, as said there will always be some imbalance so a return wire of some gauge is used.
|
|
My head hurts. Give me Bricks and Mortar PLEASE.
|
Home wiring help needed - spamcan61
