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.
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.
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.
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.
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?
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
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?
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..
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
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
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.
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.
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...
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.
Hi how2D2 just researching how to do electrical rewiring if you are not a qualified electrician. And UK rules state that you need to apply for building regulations that the work must meet Part P requirements. Just wondered (assuming you are not a qualified electrician have done electrical work?) how you go about applying to the building regs, i.e do you provide them with drawing? Do they inspect it at various times in the installation? What work you are not allowed to do? Have you you ever been refused permission to carry out any electrical work? And then obviously have a Safety check on completion. Sorry for the many questions. Hope you can help? Enjoy your videos
you have no power over me Don’t mean to be rude, but if you are asking these questions, please consult with a qualified electrician, or hire one. NICEIC, ECA, NAPIT. You would be surprised on how many burnt out consumer units and circuits I attend to in a year from people doing DIY. Be safe, get the right help.
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.
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.
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.
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.
Thank You very good video - visual and great explanation ! Thanks I love it!
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!
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...
BRILLIANT video! Thanks so much 👍🙏💥
Very clear explanation. Thank you.
This was a very helpful video thank you.Nicely explained.
Excellent
Easiest way u teach
Amazing
very easy to understand. thank you
Well done very simple and easy for beginners to understand all the best
Ive been searching this all day. Great video.
This switch installation system on lightinging look like radial circuit for sockets
Great explanation mate enjoyed your videos
Thanks a lot for this clear and helpful video! 🙏👍
thoroughly enjoyed that, suggestions for new videos, garage electrics show discrimination from the head end, bonding, bathroom and kitchen zones
Excellent video. Thanks and well done
Thank you very easy to understand
Brilliant easily explaned cheers
Very nice explanation 👌
Very nice tutorial video for beginner, I got enjoy thanks a lot
Very helpful
Another excellent video mate. 👍🏾👍🏾👍🏾
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.
Nice graphics, good work. Thank you.
Well explained as always, thanks.
2:58 it is actually 230 volts not 240 volts used in the U.K.
Thanks 👍
Very very helpful
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.
Very nice video thank you
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?
Fajnie ze dodales cos o elektryce
This is very good. It would be better to include RCDs.
Excellent
Thanks for sharing it with us
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
simple and clear !
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. 💪
Very good
Very nice and informative 👍
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?
Now that is a great video
Great info. Liked & subscribed.
Really nice video, thank you. What did you use for the graphics?
Excellent video thanks
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..
Thanks for the video. Shouldn't radial be on 16amp mcb?
20 even 25, depending on many factors
At least 20 amp
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 Very Nice Video
At 7:24 the blue wire that goes to the switch L1 terminal needs to have a brown sleeve. 🙂
Thanks for the brilliant video 👍👌👌
Thanks
Very nice 👌
Thanks good 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.
tnxs alot bro it is a v.good vidio
Fantastic
Thanks
What about Extractor ? is it also connected to Cooker connection unit ?
Good👍
Dobre video 👍🏻👍🏻👍🏻👍🏻👍🏻
Where did you learn?
Can u please explain switch to switch light circuit please
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!
I only run 1 spur off a Ring as good practice.
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.
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
All 👌
🙏 and God bless
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.
LED lights can have high inrush so don't put too many one one circuit or you'll have issues with tripping.
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...
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.
I thought radial circuits were wired in 4mm2 these days?
hi how to wire an ev charger plsease
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.
Where are you baked Sir ? Can you come and change a fuse box for me please thank you?
Does 6mm mean 6mm diameter or 6(mm)^2 the area?
6mm2 cross-sectional area of the main conductors.
6mm²
Hi how2D2 just researching how to do electrical rewiring if you are not a qualified electrician. And UK rules state that you need to apply for building regulations that the work must meet Part P requirements.
Just wondered (assuming you are not a qualified electrician have done electrical work?) how you go about applying to the building regs,
i.e do you provide them with drawing?
Do they inspect it at various times in the installation?
What work you are not allowed to do?
Have you you ever been refused permission to carry out any electrical work?
And then obviously have a Safety check on completion.
Sorry for the many questions.
Hope you can help?
Enjoy your videos
you have no power over me Don’t mean to be rude, but if you are asking these questions, please consult with a qualified electrician, or hire one. NICEIC, ECA, NAPIT. You would be surprised on how many burnt out consumer units and circuits I attend to in a year from people doing DIY. Be safe, get the right help.
@@markgilder9990 If in doubt don t stick your finger in.
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.
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!
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
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
Thanks for sharing it with us