Questions about the way my house is wired

[coursemyhorse]

Hi guys. I've some questions about how my house is wired. Built mid 80s. Terraced on an estate.
I just want to be sure it's safe. My terminology is probably poor and I don't know what all the acronyms mean always. But I will do my best to describe.

Most houses I have come across have the ability to cut off power at the consumer unit to for example all upstairs sockets, all downstairs, oven etc. My house is not wired like that. The consumer unit has from left to right:

32A breaker 1
16A breaker 2
32A breaker 3
80A RCD
Blank spare slot
6A upstairs lighting circuit
6A downstairs lighting circuit
32A upstairs electric shower
100A main switch

The first 3 breakers do sockets around the house but some sockets up and down are attached to each. In fact each one does this:

32A breaker 1 =
Kitchen sockets (but not the Hob lighter or oven)
Cooker hood extractor
hall sockets
Bedroom 1 all sockets
Landing socket

16A breaker 2 =
Lounge all sockets
Hall cupboard socket (spur from lounge socket)
1 x Kitchen socket in corner (spur from lounge socket)
Bedroom 3 all sockets
Bedroom 4 all sockets
Conservatory sockets (x5 double)

32A breaker 3 =
Cooker main oven
Cooker hob lighter


1: Is the above ok to have a house wired like that?

2: I'm also wondering why there is only a 16A breaker on the number 2 breaker, which actually does by far the most sockets. It has the entire lounge (hifi area, tv, consoles, pc) and 2 bedrooms, the fridge/freezer from the corner socket in kitchen spur, and 5 x sockets in the conservatory.
Can/should I replace this for a 32A one? I don't and have not had ANY problems with tripping.



The conservatory 5 x double sockets have been put in by someone spurring off one of the lounge sockets (ring main I think you call it?) and then out through a wall to the outside, under some decking for a few feet and then back into the conservatory through the wall. This cabling is twin and earth which measures 9.9mm x 5.5mm. It is white in colour.

At the end of the run of 5 sockets in conservatory from this spur, it finishes on what I think you call a switched fuse box. i.e. Just a big switch you can turn on or off. From this switch an SWA cable starts and goes out the conservatory wall, under ground and out to the garage giving power there. The SWA cable says on it BS5467 ELECTRIC CABLE 600/1000V BASEC Cu/XLPE 4x2.5mm 1998.

At the garage the SWA enters and goes straight into a single socket with switch and then continues out of this to another switch box which powers a tube light. There is no consumer unit or anything in the garage or conservatory. Only in the downstairs toilet is the main consumer unit.



3: I want to know if I am correct in thinking the garage is now limited to 13A from the switched fuse in conservatory.

4: If yes, can I increase this limit to 16A or 32A by taking the switched fuse out and putting a proper small consumer unit at the garage to have a proper separated lighting and socket circuit.

It is extremely difficult to wire the garage direct to the consumer unit without major operations on the house which I cannot do. (I do not own the house) but can do minor to medium stuff.


Thanks all.

 

[EFLImpudence]

Most houses I have come across have the ability to cut off power at the consumer unit to for example all upstairs sockets, all downstairs, oven etc. My house is not wired like that.

Your list would appear to contradict that.

1: Is the above ok to have a house wired like that?

Yes.

2: I'm also wondering why there is only a 16A breaker on the number 2 breaker, which actually does by far the most sockets. It has the entire lounge (hifi area, tv, consoles, pc) and 2 bedrooms, the fridge/freezer from the corner socket in kitchen spur, and 5 x sockets in the conservatory.

Can't tell from here. Perhaps it is not a ring but a radial.

Can/should I replace this for a 32A one? I don't and have not had ANY problems with tripping.

No.
There you go, then.

The conservatory 5 x double sockets have been put in by someone spurring off one of the lounge sockets (ring main I think you call it?) and then out through a wall to the outside, under some decking for a few feet and then back into the conservatory through the wall. This cabling is twin and earth which measures 9.9mm x 5.5mm.

Your measurements are a bit small but probably 2.5mm²
//www.diynot.com/wiki/Electrics:flatpvccables

At the end of the run of 5 sockets in conservatory from this spur, it finishes on what I think you call a switched fuse box. i.e. Just a big switch you can turn on or off.

No fuse then?

3: I want to know if I am correct in thinking the garage is now limited to 13A from the switched fuse in conservatory.

If there is a fuse then, yes; if not (just a switch) then 16A.

4: If yes, can I increase this limit to 16A or 32A by taking the switched fuse out and putting a proper small consumer unit at the garage to have a proper separated lighting and socket circuit.

Probably not. It would have to be inspected by someone who can tell.

It is extremely difficult to wire the garage direct to the consumer unit without major operations on the house which I cannot do. (I do not own the house) but can do minor to medium stuff.

Probably not true if it is not yours.
Perhaps that is what has happened already.

 

[ban-all-sheds]

1: Is the above ok to have a house wired like that?

Yes, as long as each circuit is properly designed (i.e. right cable size etc).

Usually showers are RCD protected though.

2: I'm also wondering why there is only a 16A breaker on the number 2 breaker, which actually does by far the most sockets. It has the entire lounge (hifi area, tv, consoles, pc) and 2 bedrooms, the fridge/freezer from the corner socket in kitchen spur, and 5 x sockets in the conservatory.

Possibly because it used to be a ring, which somewhere got broken, and rather and find & fix the break they just put a 16A breaker in and left it as two radials.

Or at some point they needed a 32A breaker (shower?) and CBA to buy one.

Can/should I replace this for a 32A one?

Not without confirming what size the cable is (throughout), and if it looks like it should be a ring, confirming that it has proper continuity on all 3 conductors. Also confirming that there aren't any unfused branches serving more than 1 socket.

I don't and have not had ANY problems with tripping.

Not surprising - these days people don't plug large loads in.

I'd leave it as it is.

The conservatory 5 x double sockets have been put in by someone spurring off one of the lounge sockets (ring main I think you call it?)

See above - it's probably not a ring.

and then out through a wall to the outside, under some decking for a few feet and then back into the conservatory through the wall.

Where does it go when it comes back?

This cabling is twin and earth which measures 9.9mm x 5.5mm. It is white in colour.

Probably 2.5mm² //www.diynot.com/wiki/Electrics:flatpvccables

At the end of the run of 5 sockets in conservatory from this spur, it finishes on what I think you call a switched fuse box. i.e. Just a big switch you can turn on or off.

Just a switch? No fuse in it?

At the garage the SWA enters and goes straight into a single socket with switch and then continues out of this to another switch box which powers a tube light.

That switch should be a fused one - lighting circuits shouldn't be on anything over 6A.

3: I want to know if I am correct in thinking the garage is now limited to 13A from the switched fuse in conservatory.

If it is fused, yes.

As the SWA cable is 4mm² and the circuit is 16A it doesn't need to be a fused switch - it would be OK to have just a switch.

4: If yes, can I increase this limit to 16A or 32A by taking the switched fuse out and putting a proper small consumer unit at the garage to have a proper separated lighting and socket circuit.

See above re 16A/32A.

No point to having a CU in the garage on an already RCD protected 16A supply. Little point on a 32A one unless you want multiple circuits - sockets can go directly on, and lights off an FCU with a 5A fuse.


[OH POO] Too slow. That's what comes of trying to do other things at the same time as typing a reply. I actually started an hour ago.[/POO]

 

[AndyPRK]

You can't put bugger Mcbs in as they are that size to protect the cables.

If they aren't tripping there isn't a problem.

Doesn't sound too bad to me.

Would like to think there is a fuse fir the shed light.

 

[coursemyhorse]

Oh right. Ok guys... I think I am with you. I will check if the switch in the garage and conservatory have a fuse in them. I can't tell without taking it apart. Don't worry, I will isolate the supply.

Also, I'm not sure I understand what a radial circuit and ring main actually are. I told you I'm no electrician!

The house is not mine, but my landlord is my mate. He's happy with me doing mostly anything really.

 

[AndyPRK]

If it has a fuse it will be obvious from the front
With a panel marked fuse

 

[ban-all-sheds]

I can't tell without taking it apart.

Then they aren't fused - the fuse holders in FCUs are visible and externally accessible.

The house is not mine, but my landlord is my mate. He's happy with me doing mostly anything really.

Replace the garage light switch with an FCU, 3A or 5A fuse.

 

[coursemyhorse]

Sorry my mistake. Yes both switches have visible fuses in the front. I flipped them out and checked and they are both 13A fuses. So the one in the conservatory before the SWA cable to the garage is 13A, and the one that is switched to the tube light is 13A as well.

I basically want to avoid overloading and want the max power possible in the garage. I'm also concerned that if I run say a pressure washer off the garage socket and an electric heater in the conservatory in the winter, plus have the TV and hifi and games console on, and PC, something could trip as it all goes back to the same 16A breaker.

 

[coursemyhorse]

and then out through a wall to the outside, under some decking for a few feet and then back into the conservatory through the wall.

Where does it go when it comes back?

It goes out the lounge wall (from the back of a lounge double socket), under decking, back into the conservatory through it's wall, then is in trunking along the wall just under the window sill which goes onto feed 5 x double sockets around the perimeter. After the final of 5 double sockets, it then comes out of the last one continuing in the trunking and goes straight into the 13A fused switch. The SWA cable to garage then feeds out the wall form this to the garage.

 

[AndyPRK]

The garage light fuse should be 3 or 5 amp.

Have you just moved in?

See what happens with your loads but it will probably be ok.

If not is maybe possible to fit a b20 MCB

 

[AndyPRK]

What else do you plan to use in the garage?

 

[coursemyhorse]

What else do you plan to use in the garage?

2 x Dual tube lights totalling approx 160watts.

Then there will be occasional use of high draw power tools like say a 1500 watt SDS drill, 1000watt Mitre Saw, 1KW pressure washer etc.

Worst case scenario would be that I was working in the garage with both lights on, plus a bench light, plus a high power power tool, stereo and laptop on as well and maybe something else I can't think of, maybe totalling say 2KW peak.

The trouble is, the garage is on the same 16A breaker as all my sockets in the lounge, one in the hall cupboard, one in the kitchen, 2 bedrooms and the conservatory. So if someone wants the electric 2KW heater on (I think we even have a 3KW one actually not sure) in the conservatory in the winter, plus the Mrs does some ironing (2400watt iron) in the lounge and then I turn on a 1500w saw in the garage whilst 3 TVs, a monitor, a PC, hifi, consoles and a Fridge run.....it could surely trip the 16A quite easily?

Or am I misunderstanding? I've never really though about it this much, but it sounds like it would be really easy to exceed a 16A breaker with just two common household items; an Iron and an Electric Heater.

?

 

[securespark]

OP:

I can see your initial confusion.

Houses are often wired floor by floor, ie one circuit for up and one for down sockets etc...

But often, they are wired on a side-to-side basis and this appears to be how yours has been done.

 

[coursemyhorse]

What max ampage can the SWA cable I have take? (Details of the cable mentioned in first post). I'm assuming it would be quite high.

If the above is not a limitation, then the next limitation becomes the cabling used that spurs from the lounge through the conservatory and then feeds the SWA cable to garage. As above, think this cable is 2.5mm internal twin and earth. A quick google suggests this can take 27A. This spur does not link back to anywhere. The sockets are all in series like a daisy chain and it just stops on the last one which is the feed to SWA to garage.

The house had a lot of things bodged. I would not be surprised if the 16A MCB was used because it's meant to be a higher one and they swapped it when they installed the shower or something. I'm not about to swap it with a higher one as obviously potentially very dangerous if the internal house wiring can't take it. Is this easy to test myself or do I need an electrician? I think the later.

 

[EFLImpudence]

The sockets are all in series like a daisy chain and it just stops on the last one which is the feed to SWA to garage.

That is a radial circuit.

If normal installation methods have been used (buried in the wall) then it could be protected by a 20A (or 25A if available) MCB.

The house had a lot of things bodged. I would not be surprised if the 16A MCB was used because it's meant to be a higher one and they swapped it when they installed the shower or something.

It was probably used because it was sufficient.

I'm not about to swap it with a higher one as obviously potentially very dangerous if the internal house wiring can't take it. Is this easy to test myself or do I need an electrician? I think the later.

Very wise.

Probably the latter but even he may not be able to tell where the cable runs.