How many double spckets on a 20amp fuse??

paddy147

I want to get the existing single sockets in the 2 upstairs bedrooms replaced with doubles.In total there are 4 single sockets,so there would be 4 double sockets.

How many double sockets can be put on a 20amp fuse in the fuseboard?

Thanks.:)

Dardania

4 doubles on a 20A is fine.

However, from reading your post, you give the impression that this is an old installation? You talk about fuses, rather than MCBs off an ELCB or RCBOs - is there a trip switch or a fuse? If there is a fuse, nowadays there must be earth leakage protection on socket circuits, usually via an ELCB feeding an MCB, or an RCBO.

Also, if the wiring was installed when there were fuses feeding the circuit, the cabling and standards could be old & poor - it's not usually a good idea to put additional load on old cabling. Also, is there adequate earth wires to each socket?

Marcus_Crassus

It's called an RCD nowadays, not an ELCB. But I agree with everything else Dardania says.

paddy147

Dardania wrote: »

4 doubles on a 20A is fine.

However, from reading your post, you give the impression that this is an old installation? You talk about fuses, rather than MCBs off an ELCB or RCBOs - is there a trip switch or a fuse? If there is a fuse, nowadays there must be earth leakage protection on socket circuits, usually via an ELCB feeding an MCB, or an RCBO.

Also, if the wiring was installed when there were fuses feeding the circuit, the cabling and standards could be old & poor - it's not usually a good idea to put additional load on old cabling. Also, is there adequate earth wires to each socket?

Thanks for the reply.

Its a modern fuseboard/mcb setup and new twin and earth wiring in the house.Fuseboard/wiring was replaced when the kitchen/dining area and bathroom was being rennovated 5 years ago.

The person in question,who owned this house,just wanted single sockets in the bedrooms at the time.So I was just wanting to know if 4 double sockets would be ok.

Now I know,thanks to you.

Thanks again.:)

Dardania

Marcus_Crassus wrote: »

It's called an RCD nowadays, not an ELCB. But I agree with everything else Dardania says.

I can never get a straight answer any time I look that topic up online, and am perpetually confused between using the name RCB or RCBO. What do you think of this post: http://www.diynot.com/forums/viewtopic.php?t=6852

Dardania

paddy147 wrote: »

Thanks for the reply.

Its a modern fuseboard/mcb setup and new twin and earth wiring in the house.Fuseboard/wiring was replaced when the kitchen/dining area and bathroom was being rennovated 5 years ago.

The person in question,who owned this house,just wanted single sockets in the bedrooms at the time.So I was just wanting to know if 4 double sockets would be ok.

Now I know,thanks to you.

Thanks again.:)

Sounds pretty good then - best of luck, and get the work certified

Marcus_Crassus

An RCD is a device which offers a level of earth leakage protection, but in itself, it cannot protect appliances, or itself, from any possible overcurrents. Accordingly, it's put in series with an MCB.

An RCBO is simply an RCD with a built in MCB in series. So it offers the same protection just all in one housed unit.

Obviously, an RCD can service many circuits with the use of an extra neutral bar; yet an RCBO can only be used on each single circuit.

Dardania, that post you linked, is accurate but slightly long-winded. I tried to simplify it down. Let me know if you're still having trouble discerning the difference.

Bruthal

Marcus_Crassus wrote: »

It's called an RCD nowadays, not an ELCB. But I agree with everything else Dardania says.

An ELCB would still seem an accurate description of it though, whether its called an RCD these days or not does not really change that.

Anyway, on a 20 amp radial socket circuit, 10 socket outlets are the max, which can be doubles or singles.

Dardania

Thanks for that - my misunderstanding is between ELCB and RCD moreso than RCD and RCBO, but it's no harm for anyone else that will stumble across this thread to get the succinct version!

It just strikes me as odd that an RCB, which sounds so similar to MCB, doesn't have the overcurrent capability of it, whereas an RCBO does - damn switchgear naming conventions!

Bruthal

Dardania wrote: »

Thanks for that - my misunderstanding is between ELCB and RCD moreso than RCD and RCBO, but it's no harm for anyone else that will stumble across this thread to get the succinct version!

There is no difference between an ELCB and an RCD anyway. The RCD was just a new name they came up with for it. The are both about current missing in the Neutral returning through the RCD/ELCB that was on the Live going out through the RCD/ELCB, using 2 current coils in opposite directions, and the third trip coil picks up the inbalance through induction. When there is no imbalance, the 2 opposing current coils cancel each other to induce zero current in the trip coil.

It just strikes me as odd that an RCB, which sounds so similar to MCB, doesn't have the overcurrent capability of it, whereas an RCBO does - damn switchgear naming conventions!

RCBO`s are a residual current breaker with overload, where as the RCD being a residual current device, does not protect against overload or Live to Neutral short circuits.

RCDs can cover a few circuits as said in another post, but they would be more prone to nuisance tripping as any slight leakage on each circuit its protecting would add up, where as if the circuits each have their own RCBO, nuisance tripping is less likely.