Appendix H of OSG: BS76712018 Table H2.1 indicates for Radial circuits with 2.5m cable you can have 20Amp breaker so long u dont exceed 50m2 floor area. With a 4mm cable you can go with 32 amp breaker and maximum floor area is 75mm. Good video as refresher.
This is top explanation . Learn a lot in a short amount of time :) . Learn also that From CU there is a 6mm cable running into the kitchen. Cooker cannot be directly connected, it needs an isolator switch. I’ve checked and most of cooker switches are 45A and the MCB controlling the 6mm cable is 32a which seems to be also the standard config…. 32a MCB and 45a cooker switch. The cooker switch has no fuse so the weakest part of the circuit is the MCB as it should be. It is rates for 45A, this is just the name or type of load/heat can handle before meltdown.
Thanks for the video. This will help me understand what the electrician is talking about when they come to do some work for me and to make sure they install what they quote for. I know the majority of electricians are on the level, but I've had one cowboy install a very sketchy system to my shed and then never gave me the part-p certificate and surprisingly his phone is no longer available.
Why would you choose the RING option over RADIAL that doesn't require you to cable back to the consumer unit? Is it safer in the event of a fault or can it take a greater load maybe? Since it's cabled from two directions I guess the load on the cables isn't as great?
I was thinking the exact same thing.I thought maybe if there was a break in the radial circuit just before or after the first socket you would lose power to all the remaining sockets in the chain, whereas if there was a break in the RIng option you would still have power to all sockets (only the Ring becomes a two Radial's due to the fault splitting the circuit) although how would you know if you had a damaged cable if there was a break and power still remained to all sockets?. I don't know. That's my best guess so far, Can someone advise, please?
The benefit of a Ring circuit is that it is capable of delivering higher currents with a small increase of wiring, i.e. the final run back to the consumer unit. For example, (and with some simplification) if you created a ring with only one socket and plugged a device that drew 4A, 2A would travel down both cables that went back to the MCB for that circuit. This allows more current to be drawn overall, hence the higher MCB rating. However, the draw back are that if a fault were to occur, and a cable were to break you may well not know that that has occurred as there is still a path to the consumer unit, and, in a worse case scenario, this could then be drawing 32A down the 2.5mm2 cable, exceeding it's rated limit and potentially becoming a fire risk. On the other hand, a Radial circuit is safer in terms of identifying fault, i.e. if it breaks you know straight away, but if you need to draw a large amount of current, you need larger cables, and due to the voltage drop, this may not just be doubling size for double power.
It stems from the war when metals were scarce. The idea is that each socket could have two inputs cabled with 1.5mm cable with the total socket current coming from both cables each at a lower current (ostensibly half each). Fine in principle but very dangerous if the ring was broken and therefore all the current would come in from one side and as the rings’ fuse rating was set for both cables to be correct you could then overcurrent the single cable possibly causing a fire. They’re also a real pain to test. Hope this helps?
2 x2.5mm cables (ring) could potentially pull 27A each? If a break in one of the legs remains hidden, then the mcb will not protect the single leg from overload/ fire, correct?
Hi. Loving your videos. I have used the wire to switch method for led spotlights in the kitchen after following your video. Excellent advice and instructions. I have a question which I hope you can answer for me. I bought a 2.7kw built in oven which comes with a plug already fitted. The plug says 16amps on it. There are no instructions as to what type of cable to use or the cartridge fuse size at the consumer unit. I was going to assume that from the plug socket to the FCU and from the FCU to the consumer unit would be a 2.5 twin and earth to a 20amp fuse at the consumer unit and the FCU would be 13amps. Is that correct? Would be grateful for your advice on this. Thank you
2.7kw is not 16 amp at 230v ! 2.7kw is less than 13amps - in fact the plug should contain a BS 1361 fuse at ...13amp . That gives a clue as to how it could be connected..
Enjoy the simplicity of your videos;I had never heard of the switch system,so i have learnt something new.Makes a lot of sense having access to all the wires in a deep backbox.What software do you use for your animated schematics?They are really effective.Good job.
8 หลายเดือนก่อน +2
At 7:24 the blue wire that goes to the switch L1 terminal needs to have a brown sleeve. 🙂
Hi, I have an issue with my landing light. When I turn the downstairs switch off I cant turn the light back on upstairs. But if I turn the downstairs on then I can turn the light on and off upstairs.
You would have muddled up the strappers for 2 way switching from point one to two. Nice simple fix, and I get plenty of call outs for problems like this.
You can add spur on spur on radial circuits. We call it branching the circuit. As long as you don't exceed 50 m² floor area. Generally, a radial circuit will have a fuse or mcb of 16/20 Amps . 30/32 Amps for a ring final circuit. Testing the installation would help determine if it's a safe functional ring.
Your video is excellent. I have smart wifi switches without capacitor. I have done few writing for my house with help of your video. How do I connect? Do you have a video?
Am I the only person that is questioning this. Is the switch connection essentially wired in series because if the first switch is not working than the others upstream from it doesn't work too because only the first one is connected to the feed.
In my understanding the live is continuous and switch only cuts off power to the individual light, looking at the back of a light switch will help to understand how it works
If your asking such questions you shouldn't actually be doing the work. The fuse rating of the head fuse will determine the minimum size tail cable that should be used.
Please explain that JB positions need to be accessible by hatch or located close enough to a light to inspect at a later date as some ppl will take what you said literally and it will be a guess as to where in the ceiling it is which is super time consuming.good video otherwise I am qualified but have forgotten some much of the theory side.there is a saying in college that you wont use half the stuff you learn on site but trust me it pays to retain some of it you may have to explain technically what you are doing at times and if you want to run your own jobs you need to know your stuff just a tip for the future sparks out there.keep learning
Do you have single-phase or 3-phase? .. Coz if you have single phase the problem will be that your induction hob already has a lot of current demand at 40A. Another problem you are going to have is with diversity. If you are going to be using the induction hob and you will have a water heater/air conditioning unit/ or multiple equipment or appliances consuming a bit of a load, then your circuit breaker is going to trip. In this case, I think you will need a 3-phase supply where you feed one phase to the induction hob alone. Hope this helps.
Apply diversity for the cooker. A separate hob and an oven should be calculated as if a stand alone cooker. A 100amp head fuse should be good to draw about 23Kw of power. A single phase supply should be more than sufficient for the average house even with an electric water heater and an induction hob and an electric oven and an electric power shower.
not too bad but all electrical wiring diagrams should be colour coded and have close up shots.always explain electrics as if you are explaining to non electricians.i.e.laymen.electrical work is very very expensive and many many people try to do things themselves.always make diagrams in bright colours and use very large images and step by step instruction.good knowledge though and well explained.
Hello how2d2 can you please do a video on how to wire an consumer unit with rcds rccb rcbo and also can you do a video on how to calculate maximum demand and diversity in actual amps for lighting circuits, ring final circuits for socket outlets, electric shower, cooker and immersion heater please reply back to this comment!!! many thanks
Here's a tip: On the new wiring colours, the best way to remember that brown is live is that if you ever touch it, then that's the same colour the inside of your pants are going to be...
While this is a good video explaining the basics it does not cover all the aspects of regulation compliance when installing these circuits, I regular carry out EICR's on installations carried out by people without the require knowledge and skills to install these circuits safely, usually resulting in large amounts of work to correct the faults found. Generally it is cheaper to get a qualified electrician to do the work especially if your work requires a building warrant as without the required test certification your installation will not be passed by build inspectors.
Hi I'm interested in getting into this line of work - do you think that completing a level 3 course at college and getting the necessary certification would be enough to find work doing inspections? Also do you generally work by yourself? Thanks!
@@irateindividual8086 I generally work alone now, but spent 20years working for firms before starting my own company. Having the technical qualifications is only half the story as far am concerned. Experience in the practical side of electrical installation is far more important. When doing electrical work its not just about knowing how things are done now you have to also know what was acceptable in the past and why a particular method of installatio was chosen when the installaton was designed. Most companies want experience in installation practice for personal doing inspections. If you set up your own company doing this your taking on alot of liability as you are certifying installations are compliant.
Fails to mention that for a cooker circuit you need to calculate and apply the diversity calculation. a 32Amp MCB may not actually be sufficient especially with an induction hob and an oven. Further 4mm2 is sufficient for a 32amp MCB/RCBO If you need to watch this stuff to understand what to do then you shouldn't be doing the work yourself.
Top video explaining basics to non electricians. Excellent.
Appendix H of OSG: BS76712018 Table H2.1 indicates for Radial circuits with 2.5m cable you can have 20Amp breaker so long u dont exceed 50m2 floor area. With a 4mm cable you can go with 32 amp breaker and maximum floor area is 75mm. Good video as refresher.
This is top explanation . Learn a lot in a short amount of time :) .
Learn also that From CU there is a 6mm cable running into the kitchen. Cooker cannot be directly connected, it needs an isolator switch. I’ve checked and most of cooker switches are 45A and the MCB controlling the 6mm cable is 32a which seems to be also the standard config…. 32a MCB and 45a cooker switch.
The cooker switch has no fuse so the weakest part of the circuit is the MCB as it should be. It is rates for 45A, this is just the name or type of load/heat can handle before meltdown.
best explanation for UK home wiring anywhere on net and youtube !
Thanks for the video. This will help me understand what the electrician is talking about when they come to do some work for me and to make sure they install what they quote for.
I know the majority of electricians are on the level, but I've had one cowboy install a very sketchy system to my shed and then never gave me the part-p certificate and surprisingly his phone is no longer available.
All your videos are the best videos on TH-cam Thanks for your hard work
Your videos are amazing! Very educational and to the point! Keep up the good work!
Yes, very good video. Like your style and animations.
You can use 4mm2 T&E for a cooker if you factor in diversity..... providing you check the specific cooker requirements
let's hope you can replace the cooker (cooktop?) with one with exactly the same spec too...
This was a very helpful video thank you.Nicely explained.
Why would you choose the RING option over RADIAL that doesn't require you to cable back to the consumer unit? Is it safer in the event of a fault or can it take a greater load maybe? Since it's cabled from two directions I guess the load on the cables isn't as great?
I was thinking the exact same thing.I thought maybe if there was a break in the radial circuit just before or after the first socket you would lose power to all the remaining sockets in the chain, whereas if there was a break in the RIng option you would still have power to all sockets (only the Ring becomes a two Radial's due to the fault splitting the circuit) although how would you know if you had a damaged cable if there was a break and power still remained to all sockets?. I don't know. That's my best guess so far, Can someone advise, please?
The benefit of a Ring circuit is that it is capable of delivering higher currents with a small increase of wiring, i.e. the final run back to the consumer unit. For example, (and with some simplification) if you created a ring with only one socket and plugged a device that drew 4A, 2A would travel down both cables that went back to the MCB for that circuit. This allows more current to be drawn overall, hence the higher MCB rating. However, the draw back are that if a fault were to occur, and a cable were to break you may well not know that that has occurred as there is still a path to the consumer unit, and, in a worse case scenario, this could then be drawing 32A down the 2.5mm2 cable, exceeding it's rated limit and potentially becoming a fire risk. On the other hand, a Radial circuit is safer in terms of identifying fault, i.e. if it breaks you know straight away, but if you need to draw a large amount of current, you need larger cables, and due to the voltage drop, this may not just be doubling size for double power.
It seems to be only us Brits that use a ring circuit.
It stems from the war when metals were scarce. The idea is that each socket could have two inputs cabled with 1.5mm cable with the total socket current coming from both cables each at a lower current (ostensibly half each). Fine in principle but very dangerous if the ring was broken and therefore all the current would come in from one side and as the rings’ fuse rating was set for both cables to be correct you could then overcurrent the single cable possibly causing a fire. They’re also a real pain to test. Hope this helps?
@@johngrannan yeah, thanks. Makes some sort of sense if the cables in a ring circuit are thinner. I never knew that.
Thank You very good video - visual and great explanation ! Thanks I love it!
BRILLIANT video! Thanks so much 👍🙏💥
Ive been searching this all day. Great video.
2 x2.5mm cables (ring) could potentially pull 27A each? If a break in one of the legs remains hidden, then the mcb will not protect the single leg from overload/ fire, correct?
Very clear explanation. Thank you.
Thanks for the video. Shouldn't radial be on 16amp mcb?
20 even 25, depending on many factors
At least 20 amp
Well done very simple and easy for beginners to understand all the best
This switch installation system on lightinging look like radial circuit for sockets
Great explanation mate enjoyed your videos
Excellent
Easiest way u teach
Amazing
Thanks a lot for this clear and helpful video! 🙏👍
Hi. Loving your videos. I have used the wire to switch method for led spotlights in the kitchen after following your video. Excellent advice and instructions. I have a question which I hope you can answer for me. I bought a 2.7kw built in oven which comes with a plug already fitted. The plug says 16amps on it. There are no instructions as to what type of cable to use or the cartridge fuse size at the consumer unit. I was going to assume that from the plug socket to the FCU and from the FCU to the consumer unit would be a 2.5 twin and earth to a 20amp fuse at the consumer unit and the FCU would be 13amps. Is that correct? Would be grateful for your advice on this. Thank you
2.7kw is not 16 amp at 230v ! 2.7kw is less than 13amps - in fact the plug should contain a BS 1361 fuse at ...13amp . That gives a clue as to how it could be connected..
thoroughly enjoyed that, suggestions for new videos, garage electrics show discrimination from the head end, bonding, bathroom and kitchen zones
Enjoy the simplicity of your videos;I had never heard of the switch system,so i have learnt something new.Makes a lot of sense having access to all the wires in a deep backbox.What software do you use for your animated schematics?They are really effective.Good job.
At 7:24 the blue wire that goes to the switch L1 terminal needs to have a brown sleeve. 🙂
very easy to understand. thank you
Really nice video, thank you. What did you use for the graphics?
Hi,
I have an issue with my landing light. When I turn the downstairs switch off I cant turn the light back on upstairs. But if I turn the downstairs on then I can turn the light on and off upstairs.
Switching wire is not connected at the switch the same way in both.
You would have muddled up the strappers for 2 way switching from point one to two. Nice simple fix, and I get plenty of call outs for problems like this.
such an amazing video thank you really
Another excellent video mate. 👍🏾👍🏾👍🏾
Hi! Can I add another socket like a spur in radial circuit? And how to check that is radial or ring? Any chance. Thanks for answer. Good video. 💪
You can add spur on spur on radial circuits. We call it branching the circuit. As long as you don't exceed 50 m² floor area. Generally, a radial circuit will have a fuse or mcb of 16/20 Amps . 30/32 Amps for a ring final circuit. Testing the installation would help determine if it's a safe functional ring.
Love it bro thanks ❤
Excellent video. Thanks and well done
2:58 it is actually 230 volts not 240 volts used in the U.K.
Your video is excellent. I have smart wifi switches without capacitor. I have done few writing for my house with help of your video. How do I connect? Do you have a video?
Nice graphics, good work. Thank you.
Am I the only person that is questioning this. Is the switch connection essentially wired in series because if the first switch is not working than the others upstream from it doesn't work too because only the first one is connected to the feed.
In my understanding the live is continuous and switch only cuts off power to the individual light, looking at the back of a light switch will help to understand how it works
Very nice explanation 👌
Brilliant easily explaned cheers
What about Extractor ? is it also connected to Cooker connection unit ?
Thank you very easy to understand
what size cable go consumer unit frome the meater? Thanks
At least 25mm²
Mostly 25mm of what I’ve seen but sometimes you can get 16mm
If your asking such questions you shouldn't actually be doing the work. The fuse rating of the head fuse will determine the minimum size tail cable that should be used.
Well explained as always, thanks.
Very helpful
Very nice tutorial video for beginner, I got enjoy thanks a lot
Please explain that JB positions need to be accessible by hatch or located close enough to a light to inspect at a later date as some ppl will take what you said literally and it will be a guess as to where in the ceiling it is which is super time consuming.good video otherwise I am qualified but have forgotten some much of the theory side.there is a saying in college that you wont use half the stuff you learn on site but trust me it pays to retain some of it you may have to explain technically what you are doing at times and if you want to run your own jobs you need to know your stuff just a tip for the future sparks out there.keep learning
With induction hob could I use 6m cable already installed induction hob states 40amp 9300klw? I've got 32rcb..do I need bigger cable.
Do you have single-phase or 3-phase? .. Coz if you have single phase the problem will be that your induction hob already has a lot of current demand at 40A. Another problem you are going to have is with diversity. If you are going to be using the induction hob and you will have a water heater/air conditioning unit/ or multiple equipment or appliances consuming a bit of a load, then your circuit breaker is going to trip. In this case, I think you will need a 3-phase supply where you feed one phase to the induction hob alone. Hope this helps.
Apply diversity for the cooker. A separate hob and an oven should be calculated as if a stand alone cooker. A 100amp head fuse should be good to draw about 23Kw of power. A single phase supply should be more than sufficient for the average house even with an electric water heater and an induction hob and an electric oven and an electric power shower.
Thanks for the brilliant video 👍👌👌
Thanks
Very nice 👌
Where did you learn?
Now that is a great video
Very very helpful
Very nice and informative 👍
simple and clear !
Very nice video thank you
Great info. Liked & subscribed.
Thanks 👍
Thanks for sharing it with us
This is very good. It would be better to include RCDs.
Dobre video 👍🏻👍🏻👍🏻👍🏻👍🏻
A radial circuit should be covered by a 16 amp mcb if using 2.5mm t&e or 20amp if using 4mm t&e (maximum lengths apply)
Came here for this comment.
Why only 16A MCB? A 2.5mm cable is rated up to 26 amps. All info I can find suggest 20A MCB is normal on a radial.
unless running to say out sheds Radial could be all sorts to much to cover here but for C.U i agree with your comment.
Building regulations book says you can use a 20A CB for a radial socket for 2.5mm cable
32amp MCB/RCBO with 4mm2 in radial configuration is permitted.
Fajnie ze dodales cos o elektryce
Excellent
Excellent video thanks
Can u please explain switch to switch light circuit please
not too bad but all electrical wiring diagrams should be colour coded and have close up shots.always explain electrics as if you are explaining to non electricians.i.e.laymen.electrical work is very very expensive and many many people try to do things themselves.always make diagrams in bright colours and use very large images and step by step instruction.good knowledge though and well explained.
Very good
Very Very Nice Video
Does 6mm mean 6mm diameter or 6(mm)^2 the area?
6mm2 cross-sectional area of the main conductors.
6mm²
I thought radial circuits were wired in 4mm2 these days?
Thanks good video
Hi mate can you make a video on how to install a light into a loft please 👍
if your asking such a question then you should not be doing the work
Hello how2d2 can you please do a video on how to wire an consumer unit with rcds rccb rcbo and also can you do a video on how to calculate maximum demand and diversity in actual amps for lighting circuits, ring final circuits for socket outlets, electric shower, cooker and immersion heater please reply back to this comment!!! many thanks
if you asking those types of questions you should not be doing the work!
tnxs alot bro it is a v.good vidio
hi how to wire an ev charger plsease
Good👍
Fantastic
Hello can I use 1.0mm cable for a radial socket?
No please... It's 2.5mm
if you want to protect it with a 6 Amp MCB/RCBO yes - If you need to ask such silly questions then you shouldn't actually be doing the work.
Here's a tip: On the new wiring colours, the best way to remember that brown is live is that if you ever touch it, then that's the same colour the inside of your pants are going to be...
We consider neutral as a live conductor when it is energised. It also carries current. You can get a nice zap of it, too 😂.
Thanks
I only run 1 spur off a Ring as good practice.
All 👌
Where are you baked Sir ? Can you come and change a fuse box for me please thank you?
🙏 and God bless
LED lights can have high inrush so don't put too many one one circuit or you'll have issues with tripping.
1.5mm heat flex is ample
This video takes no account of several crucial considerations:
Length of cable and voltage drop
Insulation lowering the current handling
Watch the beginning of the video again...
You definitely skipped the beginning of the video.
While this is a good video explaining the basics it does not cover all the aspects of regulation compliance when installing these circuits, I regular carry out EICR's on installations carried out by people without the require knowledge and skills to install these circuits safely, usually resulting in large amounts of work to correct the faults found. Generally it is cheaper to get a qualified electrician to do the work especially if your work requires a building warrant as without the required test certification your installation will not be passed by build inspectors.
Hi I'm interested in getting into this line of work - do you think that completing a level 3 course at college and getting the necessary certification would be enough to find work doing inspections? Also do you generally work by yourself? Thanks!
@@irateindividual8086 I generally work alone now, but spent 20years working for firms before starting my own company. Having the technical qualifications is only half the story as far am concerned. Experience in the practical side of electrical installation is far more important. When doing electrical work its not just about knowing how things are done now you have to also know what was acceptable in the past and why a particular method of installatio was chosen when the installaton was designed. Most companies want experience in installation practice for personal doing inspections. If you set up your own company doing this your taking on alot of liability as you are certifying installations are compliant.
@@mikeharlow3159 many thanks for the reply! Sounds like college/night school then working for a company is the right way to go then!
Fails to mention that for a cooker circuit you need to calculate and apply the diversity calculation. a 32Amp MCB may not actually be sufficient especially with an induction hob and an oven. Further 4mm2 is sufficient for a 32amp MCB/RCBO If you need to watch this stuff to understand what to do then you shouldn't be doing the work yourself.
What about people who are learning? Very informative and easy to learn
Err, just go to college and do your C&G. TH-cam don't do certification. Sorry.
Helps with people at college who are getting qualified
Thanks for sharing it with us