The use of symbols in electrics is a minefield. Electrics grew up on so many continents and in so many books. It is the tabulated current carrying capacity of the cable as in the table Iz is the current carrying capacity adjusted for continuous use at a certain load with other conditions applied. Hope this helps.
Great video Dave, but always creates more questions than answers for me. Say I’m running a cable and the lion share of the run is clipped direct but a small amount goes through a stud wall or through a piece of conduit are we choosing the worst scenario from App4 or the majority of the run? Also is my clipped direct method C no longer that if I run it in say oval conduit from the floorboard or ceiling to an accessory? As for grouping as far as I can see if a t&e cable is say running under some floor joists and I use a metal cable tie to hang a few cables together then are they now grouped if I pull the tie tight and not if I give them space for air🤷🏼♂️ Ask 100 sparkies and you get 100 different opinions which always makes me question my own installations. Did one recently which was part in 6mm t&e passing under a floor and part in 6mm SWA as it went underground outside to the garage obviously different install methods and carrying capacities etc.
The rule is that the cable sizing is correct for the factor for each part of the cables journey, and the circuit breaker is correct for each part too. So yes, a cable may be in armored where it comes into the property, but can then be clipped direct to the point of use. This is exactly the scenario that you have at the consumer unit. cable comes into the house and is then split onto different breakers at the CU.
Thanks for the reply Dave but I’m talking certification really that only has a small box both for cable type and installation method. If a particular circuit runs say partly clipped direct, then through an insulated stud wall then down to an accessory or DB in a trunking or conduit what are you supposed to state as installation method? Do you list the part of the circuit that is to be down rated the most ? So many sparkies just list as clipped direct. Many thanks.
Hi dave.. Just need to ask about the typical values we looking for when doing a test! like acceptable Zs and cable resistance etc.. Just need to know if there is any tables state these values so i can refer back to them when testing with thanks.. Again Thanks for the great effort and time given to create these educational videos. Best regards
There are lots of ZS videos on the LearnElectrics channel, take a look at the one on the link below. Put in LearnElectrics Zs in the search bar and you will find them all. Meanwhile, look at this one. ua-cam.com/video/MEXddmY61Qg/v-deo.html
What I can't seem to find a good video on is... is it acceptable to put more than one circuit into one MCB? So many different opinions out there about it and when it can be done and when it can't.
Its not good practice to mix different circuits on the same MCB. But you will see two lighting circuits on the same 6A or 5A MCB where the combined load is less than the MCB rating. Think of that as a spur starting at the consumer unit.
I have temporarily suspended the website as I am undergoing cancer Cancer treatment and cannot maintain properly. I am currently in and out of hospital and time is so very hard to find. Thought it best to concentrate on the videos and restart the website when I have finished treatment. Hope you understand and thanks for you input. Dave.
Brilliant. I never understood these pages, this is such good information. Thanks mate, you are such a good teacher.
Happy to help, thanks for watching.
13:17 pour some cool water him 😂😂😂
Thanks for watching.
Thanks for another excellent video. Inspired teaching! It’s really appreciated.
The video deals with Ib
The use of symbols in electrics is a minefield. Electrics grew up on so many continents and in so many books.
It is the tabulated current carrying capacity of the cable as in the table Iz is the current carrying capacity adjusted for continuous use at a certain load with other conditions applied.
Hope this helps.
Good revision
Great to know. if it helps then it has done its job. Good luck. Dave.
Great video Dave, but always creates more questions than answers for me.
Say I’m running a cable and the lion share of the run is clipped direct but a small amount goes through a stud wall or through a piece of conduit are we choosing the worst scenario from App4 or the majority of the run? Also is my clipped direct method C no longer that if I run it in say oval conduit from the floorboard or ceiling to an accessory? As for grouping as far as I can see if a t&e cable is say running under some floor joists and I use a metal cable tie to hang a few cables together then are they now grouped if I pull the tie tight and not if I give them space for air🤷🏼♂️
Ask 100 sparkies and you get 100 different opinions which always makes me question my own installations. Did one recently which was part in 6mm t&e passing under a floor and part in 6mm SWA as it went underground outside to the garage obviously different install methods and carrying capacities etc.
The rule is that the cable sizing is correct for the factor for each part of the cables journey, and the circuit breaker is correct for each part too. So yes, a cable may be in armored where it comes into the property, but can then be clipped direct to the point of use. This is exactly the scenario that you have at the consumer unit. cable comes into the house and is then split onto different breakers at the CU.
Thanks for the reply Dave but I’m talking certification really that only has a small box both for cable type and installation method. If a particular circuit runs say partly clipped direct, then through an insulated stud wall then down to an accessory or DB in a trunking or conduit what are you supposed to state as installation method? Do you list the part of the circuit that is to be down rated the most ? So many sparkies just list as clipped direct.
Many thanks.
Hi dave.. Just need to ask about the typical values we looking for when doing a test! like acceptable Zs and cable resistance etc.. Just need to know if there is any tables state these values so i can refer back to them when testing with thanks.. Again Thanks for the great effort and time given to create these educational videos.
Best regards
There are lots of ZS videos on the LearnElectrics channel, take a look at the one on the link below.
Put in LearnElectrics Zs in the search bar and you will find them all.
Meanwhile, look at this one.
ua-cam.com/video/MEXddmY61Qg/v-deo.html
What I can't seem to find a good video on is... is it acceptable to put more than one circuit into one MCB? So many different opinions out there about it and when it can be done and when it can't.
Its not good practice to mix different circuits on the same MCB. But you will see two lighting circuits on the same 6A or 5A MCB where the combined load is less than the MCB rating. Think of that as a spur starting at the consumer unit.
👍❤️
Thanks.
Does the leaarn electrics website not work anymore.
I have temporarily suspended the website as I am undergoing cancer Cancer treatment and cannot maintain properly. I am currently in and out of hospital and time is so very hard to find. Thought it best to concentrate on the videos and restart the website when I have finished treatment.
Hope you understand and thanks for you input. Dave.