All downstairs sockets spurred from upstairs ring main?

[Glyn1959]

Hi, my son has just bought a house and although I haven't yet checked each and every socket, all the upstairs ones I've checked have 3 x cables and all downstairs ones I've checked have 1 x cable.



This suggests to me that the downstairs sockets are spurred from an upstairs ring main! The amount of sockets on each floor is roughly the same.

Is this common? The house was built in the 70s. Was this just a lazy way to reduce cable cost and effort? It certainly makes adding additional sockets downstairs more difficult.

Is the existing set-up safe?

 

[ban-all-sheds]

This suggests to me that the downstairs sockets are spurred from an upstairs ring main!

Yup.

Is this common?

I expect so.

The house was built in the 70s. Was this just a lazy way to reduce cable cost and effort?

Does the house have a solid floor downstairs?

It certainly makes adding additional sockets downstairs more difficult.

Not as difficult as chasing a solid floor would be.

Is the existing set-up safe?

No reason for it to be unsafe, per se. Inconvenient, though.

It would not be a massive job to put the downstairs sockets on their own circuit, but you'd still have drops down the walls, assuming the house is sitting on a concrete slab.

 

[dhutch]

Thats what I have in my 4bed 40's council built that was apprently re-wired in the early 80's.

I beleve origanally all sockets where singles, but as of my aquiring, almost all are newer double sockets. My sockets almost directly corespond to each other, upstairs and downstairs, bar in the kitchen which as been re-hacked and the 4th bedroom which is now the bathroom so has no sockets (i dont really know where the ring goes here, nor as yet, have I done too much investigating!)

Its clearly not high specification wiring, but its my first house also, and to be honest its given us no issues. Only saving grace being that when the prevous owner added the conservatory it was given its own power feed in the form of a 4mm 16amp spur feeding a local ringmain, so the washing machine and tumber drier arent on the house ring main.

Which leaves just the oven (gas hob), microwave, toaster, kettle, tv, three computers, an iron, and the hoover fighting for the share of the avilable 7.5kw!.... It must get close sometimes with three of us living there but just a year in we have yet to have a nuisance trip.

I have no plans at all to upgrade it, but if I was, I would take the kitchen off the ring main and give it its own.

Lights where also clearly on one circuit origanally, wired mainly in single and earth, but had been split prior to my ownership be taking a lenght of T+E from the consumber unit up to the landing light switch and on to the attic.


Daniel

 

[Glyn1959]

Thanks for your replies. Strictly speaking should all the downstairs sockets be singles then? i.e. is having a double socket on a spur the same as having a spur off a spur?

There is one double socket at the moment which I was going to take a spur from for a FCU for a feed to a gas fire.

However, seeing the wiring arrangement, I'm thinking a dedicated spur from the upstairs ring main would be the best option. Would you agree?

Incidentally the downstairs floor is solid.

 

[ban-all-sheds]

a 4mm 16amp spur feeding a local ringmain

That can't possibly have been done by someone who knew what they were doing.

 

[Aragorn84]

maybe its not actually a ring or a spur, just a 16A radial circuit and the OP is using the wrong terms to describe it?

 

[dhutch]

That can't possibly have been done by someone who knew what they were doing.

If im honest, I dont think it is was, and im not sure why I detailed it on this thread, but that is most certainly what I understand I have. 4mm T+E radial from consumer unit, to a junction box, ring out from junction box in 2.5mm, with another spur in 2.5 to the boiler of that jb, which hence has three peices of 2.5 meeting the 4mm. Junction box being non maintance free, in the kitchen ceiling void, with the only access being the hole i hacked in the pb to find it...

But we're proberbly going off topic. The wiring is much better than the plumbing!


Daniel

 

[Glyn1959]

Two threads got joined here by mistake???

 

[ban-all-sheds]

Thanks for your replies. Strictly speaking should all the downstairs sockets be singles then? i.e. is having a double socket on a spur the same as having a spur off a spur?

No, a double socket is not the same as 2 singles, as a double is usually limited to 20A. But as long as the cable is just buried in brick/masonry, it would be OK if you did try to draw 26A from it. The socket might catch fire though...

There is one double socket at the moment which I was going to take a spur from for a FCU for a feed to a gas fire.

The FCU should go before the socket, not after. You might also need another one after the socket for the fire.

However, seeing the wiring arrangement, I'm thinking a dedicated spur from the upstairs ring main would be the best option. Would you agree?

A gas fire is a tiny electrical load, it can share with the socket.

Incidentally the downstairs floor is solid.

Thought so.

 

[Glyn1959]

"No, a double socket is not the same as 2 singles, as a double is usually limited to 20A. But as long as the cable is just buried in brick/masonry, it would be OK if you did try to draw 26A from it. The socket might catch fire though... "

Could you please clarify this statement as I want a risk free job done. FYI the cable will be buried under conduit under plaster.



Read more: //www.diynot.com/forums/electr...from-upstairs-ring-main.343235/#ixzz2BMk67lSo

 

[ban-all-sheds]

BS 1363 does not require double sockets to be able to handle more than 20A. Some makers might choose to exceed the minimum, but I don't know how many.

2.5mm² cable installed like that is rated at 23A.

 

[Glyn1959]

Just to clarify -

Option A: I am proposing extending the upstairs ring main to the existing double socket downstairs and then adding a spur from this to a FCU for the gas fire.

Option B: Leave the existing 1 x double socket on a spur as it is and have a further spur (from the upstairs ring main) to a FCU for the gas fire.

A is my preferred option, but laminate floors upstairs may make this impossible. With this in mind I need to know the best/safest way to deal with option B.

Is the existing 1 x double socket on a spur acceptable as it is or are you saying it must have a FCU before it?

I appreciate your advice

 

[dhutch]

Option A: I am proposing extending the upstairs ring main to the existing double socket downstairs and then adding a spur from this to a FCU for the gas fire.

Option B: Leave the existing 1 x double socket on a spur as it is and have a further spur (from the upstairs ring main) to a FCU for the gas fire.

Im not an electricial, but as I see it the cable laying required for the two diffrent options is, depending on the exact location of everything, almost identical.

Either way your going to have to add a aditional cable down from the ring main to ground floor either having chases out the wall, or down the existing cable run if you can pull it through.

The only other option is to take a fused spur off the unfused spur, or simply plug the fire into the existing socket with a suitable fused plug.


Daniel

 

[rjm2k]

I think you can do option B but without a new spur from upstairs (don't forget you can only take 1 spur off a socket anyway so where would your new one come from?).

Just use the existing spur, you need to put a FCU before the existing socket, then you can pretty much do what you like after the FCU.


IE

[code:1]
(current)

RING (upstairs) - SPUR - Socket

Option 1

RING (upstairs) - SPUR - FCU - Socket - Isolator - fire

Option 2

RING (upstairs) - SPUR - FCU - Socket
- Isolator - fire

[/code:1]

I'm not sure if it's better to take the Isolator in parallel from the FCU (option 2) on in series from the socket (option 1)

I guess the isolator could be a double pole switch, or a switched FCU if you want the added protection of the socket not being out of use if the fire blows a fuse (assuming the 2 fuses are different ratings like 15A on the 1st FCU and 5/3 on the 2nd depending on the needs of the fire).

Someone who's qualified (which I'm not!) will be able to say which is better.

 

[Glyn1959]

If the FCU has a switch does this not then act as an isolator?