The Ring is dead, long live the Radial!⚡

[Scolmore]

The Ring is dead, long live the Radial!
When wiring socket outlets do you:
1. Use ring final circuits
2. Use radial circuits

 

[LastManOnline]

I really meant brought of course, I didn't really buy them!!

That's, left me even more speechless?

 

[davesparks]

So we can have a large number of sockets off a 32A breaker, in fact our regulations don't limit the number, and then each appliance will have its own fuse, typically 3A, 5A or 13A, depending on what it needs.

They also, as far as I know, don't specifically limit us to a 32A maximum for socket circuits.

 

[pc1966]

They also, as far as I know, don't specifically limit us to a 32A maximum for socket circuits.

That is true, the example given is 30A rewirable or 32A MCB, etc, but it is not explicitly stated that is has to be 32A.

Seeing 20A on a normal 2.5mm ring is fine. Odd and worthy of a note, but still fine.

But having a 20A ring in 1.5mm or a 45A ring in 4mm would very much be in the WTF? sort of territory and I think most would see it as a potential risk for future use/changes/misunderstandings even if it is not actually unsafe by itself.

 

[davesparks]

That is true, the example given is 30A rewirable or 32A MCB, etc, but it is not explicitly stated that is has to be 32A.

Seeing 20A on a normal 2.5mm ring is fine. Odd and worthy of a note, but still fine.

But having a 20A ring in 1.5mm or a 45A ring in 4mm would very much be in the WTF? sort of territory and I think most would see it as a potential risk for future use/changes/misunderstandings even if it is not actually unsafe by itself.

I wouldnt suggest a ring final circuit other than 32A, it would be too much hassle to design for no advantage.

I bet most of us have seen a 40A or 45A circuit feeding a BS1363 socket and not even batted an eyelid.

 

[ipf]

That is true, the example given is 30A rewirable or 32A MCB, etc, but it is not explicitly stated that is has to be 32A.

Seeing 20A on a normal 2.5mm ring is fine. Odd and worthy of a note, but still fine.

But having a 20A ring in 1.5mm or a 45A ring in 4mm would very much be in the WTF? sort of territory and I think most would see it as a potential risk for future use/changes/misunderstandings even if it is not actually unsafe by itself.

20amp on a normal 2.5 ring may have been done after an EICR.... to attain maximum Zs? Noted, of course, as said.
I've come across a ring in 1.5, not unknown, I suppose. Should it be ripped out and replaced or protected with a 20?
[automerge]1598836149[/automerge]

I wouldnt suggest a ring final circuit other than 32A, it would be too much hassle to design for no advantage.

I bet most of us have seen a 40A or 45A circuit feeding a BS1363 socket and not even batted an eyelid.

Aye, what about a cooker unit with socket outlet?

 

[Maji236]

You have to realise that the UK (and Republic of Ireland, and a few other countries) use fused plugs.

So we can have a large number of sockets off a 32A breaker, in fact our regulations don't limit the number, and then each appliance will have its own fuse, typically 3A, 5A or 13A, depending on what it needs.

Thus fault handling is usually the appliance fuse going, for example if the flex is damaged, but if the fixed wiring has a fault or someone manages to load enough sockets up then the breaker is there to clear it.

Because of this we typically will wire a whole floor of a house on one ring circuit with the two ends going back to the same breaker, and to make the cable cost lower we use 2.5mm cable (about 13 AWG, instead of 4mm, about 11 AWG, in most cases). This also has the advantage that our CPC (earth/ground wire) has no single point of failure, typically if the ring opens on the CPC the socket is still earthed by one leg, as are all others.

Now using 4mm you can run the same sort of thing (lots of 13A sockets on a 32A breaker) but you have a much shorter length before voltage drop becomes a limit, and an open CPC leaves the remaining sockets without ground/earth protection.

So it really is just for our general purpose socket outlets - for large fixed loads like cookers, showers, water heaters, etc, we put them on their own breaker as a radial circuit.

Trying to understand the finer points of a UK consumer lashing & RCB install. The wife & I are hoping to stay in Scotland on an extended basis. It would stand to reason I should keep to my trade for work.
The mm to awg, & all the acronyms for parts are begining to sink in a bit. I also noticed your multimeters are a bit different 'looking' then I'm used to. Thanks for the clarifications. I didn't realise there is a fuse in each outlet, makes sense now. Also the individual switching is interesting too.
I really don't do alot of home wiring anymore. I do almost exclusively commercial & industrial at this point.
Cheers.

 

[DPG]

Trying to understand the finer points of a UK consumer lashing & RCB install. The wife & I are hoping to stay in Scotland on an extended basis. It would stand to reason I should keep to my trade for work.
The mm to awg, & all the acronyms for parts are begining to sink in a bit. I also noticed your multimeters are a bit different 'looking' then I'm used to. Thanks for the clarifications. I didn't realise there is a fuse in each outlet, makes sense now. Also the individual switching is interesting too.
I really don't do alot of home wiring anymore. I do almost exclusively commercial & industrial at this point.
Cheers.

The fuse is in the plug rather than the socket outlet.

 

[UNG]

Trying to understand the finer points of a UK consumer lashing & RCB install. The wife & I are hoping to stay in Scotland on an extended basis. It would stand to reason I should keep to my trade for work.
The mm to awg, & all the acronyms for parts are begining to sink in a bit. I also noticed your multimeters are a bit different 'looking' then I'm used to. Thanks for the clarifications. I didn't realise there is a fuse in each outlet, makes sense now. Also the individual switching is interesting too.
I really don't do alot of home wiring anymore. I do almost exclusively commercial & industrial at this point.
Cheers.

Are you mistaking multimeters for the Multi Function Testers (MFT's) we use for installation testing, we still use the standard multimeters but these are not capable of carrying out the tests needed to verify an installation

 

[Mike Johnson]

@Maji236

Just for you information, In France plugs are unfused, all sockets are on radials, maximum of twelve sockets in 2.5mm on 20A breaker or eight sockets in 1.5mm on 16A, kitchen supply must have at least six sockets above the worktop, water heaters and white goods have their own supply off the CU plus extract fans, power gates, roller shutters, the list goes on.
[automerge]1598861888[/automerge]
I quite often see Fluke MFT's on e-bay being sold by someone in the USA?

 

[UNG]

Edmond when you have bought up six daughters, nothing can offend you any more, none taken. Oh and as an afterthought you would be proud of me, I have just finished wiring a mosque and I did that in radial sockets exclusively not a ring final circuit in sight. The sad thing is I carefully calculated the load the client listed (very low) and thought radials would be good. I went in one day and an immersion heater had been installed by the plumber so I had to load another 3 kw onto the previously calculated load. I came in the next day and they had bought, not a 2kw oven but 3kw oven, and the gas hob I was told by the plumber could not be fitted as regulations said that no gas hobs are to be allowed any more, so they tried to get me to connect a 3.8 Kw hob as well. The radial was not looking good at this point the ceiling was in and plastered and painted, oh dear!

Isn't it strange how despite asking the customer numerous times for details what is being installed you find that once the site is boarded and skimmed the installation requirements change.
Seems to be more common these days with the choice of hobs and ovens available that range from 2Kw to 10Kw add to that the fact that washing machines and dishwashers only cold fill now and heat the water they use and the customers perception that once you have a cable in position it is a never ending source of power whatever the load

 

[Andy78]

The Ring is dead, long live the Radial!
When wiring socket outlets do you:
1. Use ring final circuits
2. Use radial circuits

When cooking a breakfast do you:
1. Use bacon
2. Use sausages

 

[LastManOnline]

@Maji236

Just for you information, In France plugs are unfused, all sockets are on radials, maximum of twelve sockets in 2.5mm on 20A breaker or eight sockets in 1.5mm on 16A, kitchen supply must have at least six sockets above the worktop, water heaters and white goods have their own supply off the CU plus extract fans, power gates, roller shutters, the list goes on.
[automerge]1598861888[/automerge]
I quite often see Fluke MFT's on e-bay being sold by someone in the USA?

That system sounds very much like what we have here with the exception of the socket circuit wired in 1.5mm and protected by a 16 amp breaker. Do our regs allow for it? Yes. But its marginal. It would have to be a clipped surface cable. Would you see it in practice? Never

 

[Mike Johnson]

No clipped surface cable either, all cable has to be double insulated and of the same c/c, therefore singles in flexible conduit or trunking.

 

[LastManOnline]

No clipped surface cable either, all cable has to be double insulated and of the same c/c, therefore singles in flexible conduit or trunking.

I, m a fan of the singles in flexible conduit. It's basically a, rewire able system. (when it's installed well). The continentals have a soft spot for the stuff.

 

[Mike Johnson]

I have never seen any sockets wired in 1.5mm in France, but I do have very limited access to other peoples installations, say about half a dozen since I retired.