5 new double sockets help please

[paultoolbox]

Hello all
Could I have some advice please
I’m converting my garage in to a play room
I’m having a new consumer box installed
I`ll be asking the electrician to leave me 2 blank fuses so when I’m ready I can run lighting cable and sockets
In my garage I’ll won’t around 5 double sockets
Should I install as a ring main
i.e. run 2.5 cable from new consumer box to the first socket then from my last socket run a cable back into to the consumer unit so I will end up with 2 x 2.5 cable into the new RCD FUSE

To put you more in the picture
I’m putting 2 doubles sockets at the far end of garage to run
A fridge , tumble dryer, and washing machine
Then 3 double sockets in new play room
Thank you Paul

 

[ricicle]

Why don't you ask your electrician ?

 

[paultoolbox]

What it is I’m converting my garage in to a play room
I’m having a new fibre glass roof so I can’t run the cables until roof is completed
Then dry lining the walls we haven’t made our minds up where to put sockets so I would rather do them myself in my own time
Just confirming the main consumer box is already in garage we had the old bakelite fuses
We now have rcd`s and mcd`s in the new consumer unit
Thank you for your help paul

 

[Taylortwocities]

If you are in England & Wales
Please remember that your electrician will only certify and notify the work that he has done.

When you (subsequently) add new circuits then you will have to raise new paperwork with the local authority (pay more £££) and take the responsibility of testing the new circuits to ensure compliance with all sorts of regulations..

 

[sparkticus]

Should I install as a ring main
i.e. run 2.5 cable from new consumer box to the first socket then from my last socket run a cable back into to the consumer unit so I will end up with 2 x 2.5 cable into the new RCD FUSE

First, to echo the caution of others, the work you are proposing requires formal inspection & test. It must be certified on completion. The new circuits that you propose to install will not be listed on the original electrical installation certificate. If something goes wrong then your insurance company will use any means possible not to pay out. Not to mention the dangers of loose connections which even experienced electricians cause sometimes. The key here is that the work is tested (with a formal procedure using calibrated test equipment) after installation allowing those types of very common mistake to be detected & corrected.

Given the loadings you mention it would be best to run a ring (a ring final circuit) protected by a 32 amp type B MCB. If it were me and assuming enough spare ways on the consumer unit then I would make it two radial circuits each protected by a 20 amp type B MCB.

Your lighting should be run in 1.0mm or 1.5mm T&E as a radial circuit protected by a 6 amp type B MCB. No matter what lights you fit you must always assume 100 watts per lighting point which should be factored into your design calculations.

Again, I encourage you to discuss this with your electrician. He may well be able to do the first fix then come back for the second fix when the room is completed.

 

[JohnW2]

....it would be best to run a ring (a ring final circuit) ..... If it were me and assuming enough spare ways on the consumer unit then I would make it two radial circuits ...

I think the OP might possibly find this advice a little confusing. Either of the options you mention would obviously be acceptable.

Kind Regards, John

 

[sparkticus]

....it would be best to run a ring (a ring final circuit) ..... If it were me and assuming enough spare ways on the consumer unit then I would make it two radial circuits ...

I think the OP might possibly find this advice a little confusing. Either of the options you mention would obviously be acceptable.

Yes on reflection it confused me

Another go:

A ring final circuit (as you have suggested) protected by a 32 amp type B MCB will be fine (provided it is installed correctly, inspected & tested)

But as an alternative my personal preference would be as follows:
I would run two separate radial circuits (a radial is a one way journey - does not loop back to the consumer unit) each radial protected with a 20 amp type B MCB.

What is the advantage of two radials over one ring? If you plan the socket position VS the circuit allocation correctly then you could avoid the fridge/freezer being "tripped out" by a dodgy washing machine (for example)

In other words if one radial circuit is tripped by the washing machine the other radial circuit (where your fridge/freezer is plugged in) is still alive and well.

 

[JohnW2]

What is the advantage of two radials over one ring? If you plan the socket position VS the circuit allocation correctly then you could avoid the fridge/freezer being "tripped out" by a dodgy washing machine (for example)
In other words if one radial circuit is tripped by the washing machine the other radial circuit (where your fridge/freezer is plugged in) is still alive and well.

True, with the proviso that the tripping you are talking about is tripping of an MCB, which is a fairly rare consequence of an iffy appliance. Far more likely is tripping of an RCD. Unless the two radials are fed from different RCDs, or have their own RCBOs, such tripping due to the washing machine would obviously take out the fridge/freezer as well.

More generally, one can argue this point both ways. Having a freezer on a dedicated or near-deciated circuit certainly reduces the risk of it become dead due to a fault on something else. However, unless the freezer has a battery-operated alarm (or more sophisticated alarm systems), it also makes it less likely that a tripping of the freezer circuit (for whatever reason, most probably a fault in the freeezer itself) will be noticed quickly, since little or nothing else would be affected. Just as fire alarms, I prefer to have freezers on circuits whose failure will be rapidly noticed.

Also, to be balanced, one should perhaps mention that there are also some potential 'pros', as well as 'cons' of ring final circuits (such as 'belt and braces' CPC).

Kind Regards, John.

 

[sparkticus]

True, with the proviso that the tripping you are talking about is tripping of an MCB, which is a fairly rare consequence of an iffy appliance. Far more likely is tripping of an RCD. Unless the two radials are fed from different RCDs, or have their own RCBOs, such tripping due to the washing machine would obviously take out the fridge/freezer as well.

Yes a good point. More likely that an RCD will trip or both RCD and MCB. I like RCBOs (where earth leakage protection is required/appropriate) and use them wherever possible in preference over multiple circuits on an RCD but I accept that they are are expensive and don't suit all budgets. I just have a personal preference for radials and like the discrimination they offer.

More generally, one can argue this point both ways. Having a freezer on a dedicated or near-deciated circuit certainly reduces the risk of it become dead due to a fault on something else. However, unless the freezer has a battery-operated alarm (or more sophisticated alarm systems), it also makes it less likely that a tripping of the freezer circuit (for whatever reason, most probably a fault in the freeezer itself) will be noticed quickly, since little or nothing else would be affected. Just as fire alarms, I prefer to have freezers on circuits whose failure will be rapidly noticed.

Not for everyone I realise but when I re-wired my own house two years ago I put in 18 circuits (all radials) I placed my interlinked smoke/heat alarms on a dedicated circuit protected by a 6 amp type B RCBO. The circuit is monitored by a current sensing relay (set at 250mA) the relays NC contacts (which are of course open when current is sensed) is in series with a beeper fed from a non-rcd protected dedicated circuit and backed up by an alarm battery. all the control "gubbins" including the battery are in a large metal box plumbed directly to the CU with a short 100mm length of metal conduit. Of course my wife thinks I should make better use of my time

Also, to be balanced, one should perhaps mention that there are also some potential 'pros', as well as 'cons' of ring final circuits (such as 'belt and braces' CPC).

That is true but equally true in the same context is the possibility of abnormal loading when someone fiddles with a socket and leaves a loose neutral/live.

 

[JohnW2]

Yes a good point. More likely that an RCD will trip or both RCD and MCB. I like RCBOs (where earth leakage protection is required/appropriate) and use them wherever possible in preference over multiple circuits on an RCD but I accept that they are are expensive and don't suit all budgets. I just have a personal preference for radials and like the discrimination they offer.

A very reasonable viewpoint. As we've discussed, there is at least one potential downside of having things like freezers on dedicated or near-dedicated circuits with their own RCBOs, unless alarms are implemented (see below).

...I placed my interlinked smoke/heat alarms on a dedicated circuit protected by a 6 amp type B RCBO. The circuit is monitored by a current sensing relay (set at 250mA) the relays NC contacts (which are of course open when current is sensed) is in series with a beeper fed from a non-rcd protected dedicated circuit and backed up by an alarm battery.

That, of course, is exactly the sort of thing I meant when I talked of "(or more sophisticated alarm systems)" and I have several such systems in my house.

...That is true but equally true in the same context is the possibility of abnormal loading when someone fiddles with a socket and leaves a loose neutral/live.

Exactly. As I implied, much of the ring/radial debate is about swings and roundabouts - although, as many others have said, I strongly suspect that had there not been an issue (or percveived issue) of copper availability/cost at the time, ring final circuits would probably never have been conceived or allowed.

Kind Regards, John.

 

[paultoolbox]

thank you all
wow what a lot of replys more the better i suppose
he has told me there are 3 blank spaces left and told me to put the sockets on a ring ?
so i will only need a 6amp mcb and a 32amp mcb
i will take heed to all your wise words
What a lot of new regulations
One final word
I’m running the cable sockets down the wall then dry lining The walls
what do regulation say about covering cables with a metal cladding
( trunking )
As it I was just going to pin cables to walls ?
also i do have a socket tester plug with the 3 neron lights on it any good better than nothing a
thank you paul

 

[sparkticus]

As it I was just going to pin cables to walls ?

Just clip the cables to the walls. No need for trunking. keep the cables with nice straight drops so that everyone knows where to expect the cables.

also i do have a socket tester plug with the 3 neron lights on it any good better than nothing

It will not tell you that an earth or live or neutral is loose/not connected in a ring circuit. In general, they are not reliable items of test equipment. They do confirm polarity but do not "stress" the circuit with enough current to produce reliable indications of good connections. They do not confirm that a fault path or an earth fault path is adequate to cause reliable MCB/RCD operation.

 

[riveralt]

so i will only need a 6amp mcb and a 32amp mcb

No you won't!

i will take heed to all your wise words

Actually you are ignoring those wise words and carrying on regardless.

What a lot of new regulations

most of them are not new.

also i do have a socket tester plug with the 3 neron lights on it any good better than nothing a
thank you paul

Your kidding right
How are you going to measure continuity, insulation resistance, polarity, earth loop impedance et al with that.

You need one set of these..http://www.kewtechcorp.com/products/kits/KT17B.htm