Odd wiring in consumer box

[deefadog]

Hi all, great forums, they have helped me for a while, now I guess I'll start posting some questions

I have the old style consumer box which I have just changed the pull out fuses with newer mcb trip switches, i have (6A, 16A and 2x 32A). When I was changing them I noticed that the last 32A (I assumed was for the cooker & sockets becuase the second one in is just for the shower) and the 16A did the same thing, for example take the 32A fuse out and all sockets and cooker worked, put the 32A back in and pull the 16A and everything still worked, pulled the two and every socket and the cooker was off.

This can't be right surelly? What can i do to check what's wrong and how can I fix it?

btw i have a bungalow

Thanks for any help.

Deef

 

[securespark]

First of all, the cooker should be on its own, not with the sockets.

I suspect that the ring conductors in the CU have been mixed up, with one ring conductor on one fuse and the other plus the cooker on another. This means that until you pull both fuses, both circuits are live.

If you have a ring circuit, you should have 2 x 2.5. A cooker circuit should be one slightly thicker conductor.

You need to get familiar with a multi meter and double check that the ring is OK before you terminate the conductors correctly in the CU.

 

[deefadog]

Thanks for the reply, I need to trace each wire and draw the seperate circuits into i flowchart I think, so i know where I am, then I can test it.

When i switch off the main switch on the box, will there be any live connections within the box that are open? or is it ok to take the front of the box off once the switch is off?

Also what should my fuses controll?

Cooker on it's own - 32A

Shower on it's own - 32A

16A ? - this for the sockets?

6A - lighting circuit

Thanks

 

[securespark]

The tails feeding the CU from the meter will still be alive unless you have a seperate isolator which makes them dead at the same time as the CU. If not, take great care.

It is difficult to say what's what without being there, but your 16A circuit could be an immersion heater or other radial circuit.

 

[ban-all-sheds]

Basically Deef you don't have enough capacity in your 4-way fusebox for the number of circuits you need.

Time to get a bigger CU.

 

[deefadog]

Thanks guyz.

What should the correct wiring be? As I have just had a combi boiler fiitted so there will be no need for the immersion heater or the electric shower! I am guessing that the previous owners put the sockets and oven together so they could have a spare socket for the shower!

So is this the correct way i shouild do this =

6A - Lighting - (ok stays the same)

16A - spare - could I use this for my garage (2x tube lights 1x socket and tumble dryer) or rewire this for a 32A wire?

32A - Oven only

32A - sockets only

Sound ok?

 

[ban-all-sheds]

16A won't leave you much spare once the TD is running.

And sockets in a garage, not to mention the ground floor, should have RCD protection.

And the fridge/freezer should be on a circuit that doesn't have RCD protection.

And the kitchen often benefits from a separate ring.

And it's good to have the lights split over two circuits so that if you lose one you still have some light.

And you might want a bigger cooker one day.

And you might like to consider mains powered smoke alarms.

And you might decide you'd like a burglar alarm.


Basically you should seriously consider replacing your 4-way fusebox with a split-load CU.

 

[deefadog]

I see your point thank you very much

Can you give me some more info on a split-load CU please how many fuses should I have? I guess some are left blank for future use?

Also as I have a bungalow and access is easy up in the attic could I have the cables coming up from the CU (sunk into the wall) straight into seperate Junction boxes? and then start the rings etc from there? exactly the same thing I guess just makes it easier if I ever want to expand again! as some of the junction boxes would only have the spare cables going to them (acting as a blank) so i don't have to channel the walls out again at a later date. Is this ok?

 

[deefadog]

Any info on the above please?

 

[plugwash]

a split load CU has a main switch theat covers everything

stuff like lighting alarams and ideally freezers (if you can be bothered putting in a dedicated freezer cuircuit) should be placed on the non-rcd side

sockets and showers should be placed on the rcd side

the rest it doesn't really matter which side you put them on

it is a good idea to buy one with some spare space so you don't run out again in the near future

 

[deefadog]

Thankyou, will head off to TLC

 

[plugwash]

sorry that post was incomplete i was tired when i posted it

i meant to say a split load CU has a main switch which coverres everything and a rcd which convers only some cuircuits

screwfix have a good deal on a mk split load CU full of breakers
http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=68452&id=64020

 

[deefadog]

Thanks for the info, great stuff!

I'll compare some prices

 

[ban-all-sheds]

Don't just buy a CU because it looks like a good deal.

Do a proper design of your requirements, and think about what you might do in the future - your CU should be chosen to support your design, rather than the other way around.

 

[deefadog]

Good point! I am still a bit lost most of the post I have read are directed at house's with upstairs and downstairs with seperate circuits. I live in a bungalow so my requirements I am guessing are going to be a bit less than a two level house!

I think this will do me:

1 x 32A - for cooker - RCD protected

1x 32A - sockets

1 x 32A - garage - RCD protected

1 x 32A - Spare (for shower future) - RCD protected

1 x 32A - Spare

1 x 6A - lights

1 x 6A - Spare

This should be plenty for what i need, any thing I missed?

If I plug the fridge into the 32A socket ring, can I get an rcd switch to plug into? saves routing a seperate cable just for one appliance!

Thanks again, you'll have to go easy on me if I repeat my questions just want to get it all sorted in my head. great help here btw

Take care