Ring circuit wiring

[ajj]

I am   re wiring house after building new kitchen. One ring for sockets for new kitchen completed using 2.5 twin cable with seperate earth cable run alongside. 2nd ring circuit nearly completed using  3 core 2.5 cable with earth , but this cable used up . Will it be ok to use  2.5 twin cable with seperate earth wire for last 3 sockets and return to fuse box , or advisable to purchase more 3 core cable . Thanks aj .

[bankruatsteve]

Ring circuits not a good idea in Thailand.  Maybe Crossy can explain why when he gets in.

[Crossy]

Do NOT wire ring finals unless you are also using BS1363 outlets and fused plugs, even then 20A radials on 2.5mm² are preferred (even in the UK).

 

Best to wire as two radials @ 20A each rather than a 32A ring.

 

Twin plus separate earth will be fine.

 

 

 

 

 

[bankruatsteve]

Just to add... ring circuits (while they may have had a good reason in England eons ago) are just not a sensible thing to do.  They do not add safety, they do not save energy, and they will most certainly confuse anybody who might need to deal with it.  Don't do rings.

[cornishcarlos]

Would this sort of set up be ok but with 20A fuses ?

[Crossy]

Yup Carlos, that's a typical "tree" arrangement, in 2.5mm² cable on a 20A breaker it's just fine.

 

[cornishcarlos]

Yup Carlos, that's a typical "tree" arrangement, in 2.5mm² cable on a 20A breaker it's just fine.
 

Cool... How many sockets can you run from each junction box ?
Plus is it a similar arrangement for light switches ?

Cheers and sorry to jump in on the thread but it's interesting

[Crossy]

There is actually no limit on how many outlets you can run off each breaker junction box other than common sense. I wouldn't go over around 10 double outlets per breaker, but that's really just personal preference.

 

It all depends upon load, a kitchen with many heavy current appliances (kettle, microwave, toaster, worktop oven etc etc) may need two 20A circuits whereas the bedrooms with probably only a TV and phone chargers with the occasional hair-dryer would likely all be fine on a single 20A circuit.

 

You can wire your lights in a similar way, we put a large box in the ceiling space at the top of each switch drop (and outlet drop too) and did all the interconnects in there using Wago push connectors (you could use wire nuts if you like). We also dropped a neutral to each switch box, it's not normally needed but is handy to have if you want fancy light controllers or an extra (low power) outlet.

 

The "major" interconnect boxes have a removable hatch in the ceiling so they can be accessed for adding in that "forgotten" light or ceiling fan etc. A dead handy feature that our ceiling chap did without being asked. Yes, I've used them several times :)

 

[wayned]

In the US we don't normally have a separate circuit for the lights.  The power for the lights comes from the radial and goes directly to the light, usually 12awg,  and then a switch leg is dropped to the switch box.  There usually isn't a neutral leg in the switch box unless it also has a socket.

 

Most US houses do not have drop lights in every room.  The bedrooms and living rooms normally don't and they have switchable sockets so the room lighting is plugged into that, either a lamp or a "swag" fixture.  Of course when you buy a new track house the switchable socket is never in the right location to match your final interior decor!

[Crossy]

Yeah Wayne, most homes here in Thailand that aren't built by Brits or Aussies have lights and power on the same circuits.

 

I think separate lights came from the same stable as ring-finals (post-war copper saving), you can use 1mm² cable on the lights if you use a smaller fuse / MCB.

 

It is handy to still have either lighting or outlets functioning when working on the other circuit.

[bankruatsteve]

43 minutes ago, wayned said:

In the US we don't normally have a separate circuit for the lights.  The power for the lights comes from the radial and goes directly to the light, usually 12awg,  and then a switch leg is dropped to the switch box.  There usually isn't a neutral leg in the switch box unless it also has a socket.

 

Most US houses do not have drop lights in every room.  The bedrooms and living rooms normally don't and they have switchable sockets so the room lighting is plugged into that, either a lamp or a "swag" fixture.  Of course when you buy a new track house the switchable socket is never in the right location to match your final interior decor!

 

Hmmm - perhaps a regional convention?  All the homes I have experience with (throughout the mid-west) had separate circuits for lights.  Switchable sockets are common in bedrooms.  Whatever.

[ajj]

Thanks for replies,will remove return from last socket to fuse box to create two radial circuits from ring circuit . Question  for Crossy ,have purchased consumwr unit with rcbo and surge protectorwith 9 fuses.2/32  2/20 2/16    3/10amp.for small house now realise this is tight in no but cant change . Was going to wire like this : 1/32 water heater kitchen . 2/32shower . 3/20 shower.4/20 radial sockets kitchen. 5/16radial sockets to old house (only 8sockets for 1 bedroom and 1lounge.)     6/16 air con 9000btu. 7/10 air con 9000btu.  8/lights kitchen . 9/10 lights old house. Is this ok, or would you change .Possibly seperate additional breakers to air con, or other ideas .thanks Aj.

[Crossy]

Hi ajj, yeah that works for me.

 

If space is tight you could put both aircons on the 16A, even if you wire them in 1.5mm² (2.5mm² would be recommended) there's no danger of overloading the cable.

 

[ajj]

Thanks for advice will wire 2 air cond.on2.5 cable to one 16amp breaker .

[taninthai]

On Thursday, December 08, 2016 at 8:51 PM, cornishcarlos said:

Would this sort of set up be ok but with 20A fuses ?

I have  just just wired my sockets in a ring main ....would never wire them as in above diagram,,,I call that spider wiring the Thais love it ....how you supposed toget an end of line test reading......is there any other reason people are saying don't wire ring circuits ,,,it confusing other people is not really a valid reason???

[Crossy]

1 hour ago, taninthai said:

I have  just just wired my sockets in a ring main ....would never wire them as in above diagram,,,I call that spider wiring the Thais love it ....how you supposed toget an end of line test reading......is there any other reason people are saying don't wire ring circuits ,,,it confusing other people is not really a valid reason???

 

I really, really hope your ring final isn't on a 32A breaker like it would be in the UK.

 

A 32A will happily carry 40A all day without blinking, not so a Thai 15A outlet / plug / flex, a 260% overload has serious potential for a fire!

 

OK it's not going to be overloaded until uncle plugs in his welder or the like. But you have potentially zero protection for your tiny appliance flexes too (no 13A plug fuse to protect it here).

 

Also note, rings are falling out of favour in the UK too. A 2.5mm² ring can handle a 32A breaker, split that into two radials on separate 20A breakers and you get an extra 8A for the cost of an MCB :)

 

 

[r136dg]

I noticed those 15amp outlet/plugs are everywhere, even the panasonics. Where can one find some 20amp & heavier?

[Crossy]

10 minutes ago, r136dg said:

I noticed those 15amp outlet/plugs are everywhere, even the panasonics. Where can one find some 20amp & heavier?

 

Anything bigger than the regular Thai (US) 15A outlet would be "commando" style in 16A and 32A, this type of thing:-

 

 

[sometimewoodworker]

4 hours ago, taninthai said:

I have  just just wired my sockets in a ring main ....would never wire them as in above diagram,,,I call that spider wiring the Thais love it ....how you supposed toget an end of line test reading......is there any other reason people are saying don't wire ring circuits ,,,it confusing other people is not really a valid reason???

The silent failure mode of a ring final, the potential for borrowed neutrals, difficulties in isolating faults, difficulties in designing the ring to be balanced, are all reasons it is being phased out in domestic use in the only country that still has quite a lot of them.

 

Your so called "spider wiring" the radial final is the preferred system in all counties 

[taninthai]

crossys   points are very valid and i will indeed pull out a link to make 2 radials, will infact save me buying more cable as i was short on the last leg back to the board so the link i pull out will get me back to the board i could just leave it as is without putting final leg bag to board. 

 

sometime woodworker... we would never wire a radial in the uk as shown in the diagram above that wood be considered a proper bodge job.

 

arjen... if they completely dont know anything about electric to the point of different types of circuits from a quick visual inspection of consumer unit they shouldnt be touching the electrics in the first place so confusing other people is not really a valid reason.

 

yep ring circuits not as popular in the uk as they used to be but we are still wiring them in the uk and if its a radial they tend to upgrade cable to 4mm2.

can't see why you would wire a radial as diagram ...why have a junction box if you dont need one..

 

thanks for all replies especially crossy coming up with decent answers again:)

[Crossy]

6 hours ago, taninthai said:

arjen... if they completely dont know anything about electric to the point of different types of circuits from a quick visual inspection of consumer unit they shouldnt be touching the electrics in the first place so confusing other people is not really a valid reason.

 

It's more likely they've never experienced a ring (or even know such a thing exists). Even an Aussie sparks on seeing two wires in a breaker would likely assume two radials. Rings just aren't used anywhere outside the UK, once again Britain leads the world, from behind.

 

There are very good Thai electricians, but none of them are working on domestic (apart from major developments, and even then ... ), they're working on the mega-projects or earning pots in O&G.

[esprit]

2 hours ago, Crossy said:

 

It's more likely they've never experienced a ring (or even know such a thing exists). Even an Aussie sparks on seeing two wires in a breaker would likely assume two radials. Rings just aren't used anywhere outside the UK, once again Britain leads the world, from behind.

 

There are very good Thai electricians, but none of them are working on domestic (apart from major developments, and even then ... ), they're working on the mega-projects or earning pots in O&G.

Crossy, that is a piece of information that I never realised regarding the UK being the only country using a ring circuit.  amassing isn't it being bought up to consider that is the norm, only later in life to find out it is the exception. I'll keep that one for the pub quizzes in my next life !!!

[Crossy]

Yup, even places such as Singapore, Hong Kong and Malaysia which use BS1363 13A plugs don't use rings, everything is on radials.