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  1. Pretty Mouth

    Max circuit length for LEDs powered by constant current driver.

    Hi all. Constant current LED lighting is a new concept to me. Not that difficult to get the head around, but I cannot find an answer to the following question: How do I determine the maximum length of a ELV LED lighting circuit powered by a constant current driver? For a constant voltage ELV...
  2. J

    Length of cable

    Does the length of cable de rate the cable as it creates a greater resistance and as a result heats up the cable reducing its current carrying capacities?
  3. D

    Length of tails

    Afternoon all, New to the site so thanks in advance. Currently working on a new build, the supply was installed last week (new build) 80a fuse installed, EON installed the meter this week with 100a DP switch. All fitted within the external meter box. I’m looking to run tails, ideally I need to...
  4. B

    Cable length calculation

    Hi people, I'm carrying out an online course to gain my qld electrical licence. Been a good while since calculating cable length using equations and regs books. Can anyone guide me to the correct equations please Thanks in advance
  5. S

    Doorbells again - volt drop / max bell wire length

    Hi Folks I've been trying to work out whether a doorbell will work with approximately 16m run of bell wire. I've tried to find out volt drop, resistance (to calculate volt drop), or even CSA of typical bell wire. But no luck. I tested an approx. 3m length with my MFT and got 0.87 Ohms. That...
  6. C

    How to increase cable length?

    Hi guys, Im very new to this forum so thanks for hearing me out. I have an led light that is waterproof. The issue im having is that the cable is not long enough for its purpose. I needed some help or advice as to how i could find a cable attachment to increase its length.. i have attached pics...
  7. G

    Length of tails between meter and consumer unit

    Hi, I am currently studying for my 18th edition regs update exam and came across a video by SparkyNinja on you tube. I think SparkyNinja is very good and produces high quality content. However I disagree with his interpretation of regulation 434.2.1 (i) In his video he says you need a fused...
  8. Zdb

    Expected circuit length (R1+R2)

    Came across this table from on old thread: Is there a table of expected R1+R2 results in BS7671? - https://www.electriciansforums.net/threads/is-there-a-table-of-expected-r1-r2-results-in-bs7671.103412/ I'm just wondering if anyone has the original or a more detailed version that they...
  9. F

    Siren sounder wire length

    This is something I have never come across before even though I have installed a good few alarm systems in my time as a DIYer. I know it is a cheapo alarm but it shouldn't be any different. It came with a little siren and about two feet of flex, black and red two core. I intended to put in to...
  10. T

    Insulation resistance test on length of SWA cable

    Doing new supplies for a school new Shneider 3 phase & N MCCB panel board. 50mm 4 core SWA one end made off in the board earth fly lead from banjo to earth terminal. The other end gland made off in gland (fly lead not made off yet) 3 phases and neutral just hanging there. Done installation...
  11. Y

    Ring circuit cable length

    Hi all I have a ring circuit with 13 sockets. 2.5 mm 3 core cable. My floor area is 60 sqm My question is what is the maximum wire length for a single ring circuit? I used 92 meters of wire for the whole ring circuit. Also I only had a c type rcbo available at my local electrician. Will this...
  12. D

    On off car battery switch - cable length?

    Hi, My car is Mitsubishi Colt 1.3 (1998), and I'd like to install a battery on / off switch in the interior of the car. My question is: would it be ok to use around 1.5 meter length of normal battery cable? The idea is to connect it to the battery negative terminal and to the existing...
  13. 8

    Max length of meter tails

    Ive been asked to look at the electrical installation at a large 5 bed property with an attached annexe that the owners are converting into a 2 bed holiday let. There's one supply cable that comes into the annexe for the entire property . This is currently routed via a single meter to a CU . 2...
  14. P

    The length of a female minute

    Do women have a different size of minute? I ask because if my wife says "I'll only be a minute" I know she will be at least half an hour. When I get commanded to carry out a job, and I know it will take a couple of hours, her estimate is "It'll only take a few minutes". Can any one explain?
  15. Andy C

    Crimping to extend cable length.

    Hi all and thanks for the help so far. Re crimping, I have read posts regarding this before. I have just seen those heat shrink solder connections. I was going to use normal red and blue crimps then heat shrink each individual core then heat shrink over the whole T&E. What are peoples...
  16. N

    Meter Tails

    Hi, On site dispute needs sorting. We have a consumer unit 3m away as in distance (not cable length) from DNO (outside meter box, flush with wall). We currently have a 25mm 3 core SWA from DNO to consumer unit. Running within the fabric of building and it's protected from the nails and the like...
  17. R

    Lighting circuit cable selection

    For selecting the correct cable size how do I determine the cable length in a loop in lighting circuit? Will it be the distance from the consumer unit to the final ceiling rose? Do I have to take into account the cables running from each ceiling rose to the light switch? I have attached a...
  18. yellowvanman

    EICR Observations

    Would like to get other opinions on the following observations of a property that was rewired 10 years ago: 1) Excessively long ring - r1/rn/r2 = 1.56/1.56/2.48 2) Mismatch of RCBO - Hager RCBO in Legrand CFU with othe rLegrand MCBs
  19. R

    Loose Wire Underfloor Heating Cable Can Be Cut To Length?

    I often install loose wire systems , mainly because of the shape of the room and the fittings like showers and toilets , the question is are there any out there that can be trimmed to length and sealed , the amount of times I have to keep living and relaying to use the full length is a pain ....
  20. H

    Rcbo functional earth location

    When wiring an rcbo where do you tend to put the functional earth? I'm assuming it will be tricky to ensure the small functional earth will get a good grip when placed with its corresponding cpc, so do you put your functional earth in its own terminal?
  21. Andy78

    led extrusion/channel.

    Does anyone know of a good online supplier of recessed aluminium channel for led tape ? The numerous wholesalers round here all do not seem to carry it.
  22. L

    Volt drop

    Hi I've a few questions regarding volt drop. Apologies if its a little longwinded but I'd like to get my head around everything. An example scenario is a section board with a TP sub main to lighting and power board (DB2) Calculations for circuit : Supply Voltage = 400 Volts Ib - Design...
  23. Y

    DC Volt Drop Calc

    Hi all, I appreciate this has probably been posted to death but the search wont load on my phone. I have to calculate for Volt drop in a DC circuit, There's next to no load (2 amps max) the cable is 4mm pvc twin, and ln a loop from the control unit to the loads. OveralL Length 50m Is the calc...
  24. sam400

    1m sds drill bits

    Can anyone recommend me a decent 1m sds drill bit, I've managed to shear a few of them off at the chuck.
  25. yellowvanman

    LED Tape

    Anyone installed long lengths of this? Customer wants it stuck on top of a picture rail around a room (about 20m), there will also be breaks in the picture rail for doors etc. Just need a heads up on pitfalls with this sort of length required.
  26. S

    Domestic Multiple LED strip power issue

    Hi people. Bought a 12v dc power splitter cable to power 2 5meter length 5050 colour change LED strip lights. noticed the next day that the cable melted really bad. Im not sure why this is? the ac-dc is a 6amp 72watt and the total power of both strips should be 48watt so that should be fine...
  27. M

    Volt drop

    Hi, Im a fairly new sparky, So just wanted to get a little idea as im not 100% sure, Im adding 12m of 1.5mm cable in trunking into a conservatory from a fcu of the ring main the volt drop for this part would be 4.5v so i may need to up the cable size. But what i need to know or confirm is what...
  28. V

    Hi I'm new here! Have a question on Radial & Ring circuits

    I am a DIY and working on an extension on my home. I found out that one area of my house is on a 4mm radial for sockets on a 32amp mcb which I know is fine. Now the question is Can I safely continue wiring 4mm radial? Total length from distribution to last socket will be around 60metres with 12...
  29. N

    0.00 ohms r1+r2 on radial circuit?

    Hi all, I've tested several radial circuits and only getting 0.00 ohms on the r+r2 test (zero'd leads) 2 of the radials only supplies one socket each and are approx. 3 metres in total length. (zs 0.25 and 0.21) Another radial only supplies one socket and is appox. 5m in length. (zs 0.35) The...
  30. H

    Help with EICR code!

    Hi, just wondered what your thoughts are on this, 3 bed town house Whole house ring final, mixture of 2.5 / 1.0 & 2.5 / 1.5 twin and earth cables, End to ends = 0.78, 0.78, 1.6. R1r2 = 0.61 (spur). ZS = 0.66! BS7671 recommends a max of 100 square meters which using 2.5/1.5 = an r1r2 of...
  31. R

    I Can't See How This Works...

    Here's the scenario: Ring Final Circuit Design Current = 20 Amps Circuit Breaker = 32 Amps (may well be using an RCBO - but that's another story) Ring length total (end to end) < 45 meters Correction Factors - grouping factor of 0.78 (reference method E with 9 other circuits) Gives an Iz of...
  32. G

    how to cure a blowing fuse

    Some latvian contractors had complained about a welder blowing a fuse on an extension lead repeatedly,Finally they announced they didn't need the electrician calling out as they had resolved the issue,yes that is a piece of an M6 bolt!
  33. M

    Voltage drop calculation

    Hello everyone just want a little help how you would calculate the volt drop if 230 single phase heater circuit line & neutral conductors combined resistance of 0.68 Temperature at 20 degrees and load current of 16A? show calculations got this in my 2395 today wanna make sure I used the...
  34. A

    two methods to verify a low ohm meter i think is not working properly?

    I am looking to answer a question on a course, and cant think of 2 methods to verify readings on a low ohm meter....please help?
  35. Y

    Voltage drop question

    Hi everybody. I have a question (still learning, passed 17th edition and part P, but I'm not yet registered). If you use formula from On-Site Guide p.140 what the design current you put in the formula, to calculate max length of cable for 11.5V. If 32amp then the maximum length of ring final...
  36. J

    Cable sizing for 24V LED lighting

    I believe I have been wrongly advised by my supplier about sizing cable for a lighting installation and I was hoping that someone with more experience of DC cabling will be able to set me straight. We are looking to install some LED strips to a coffered ceiling above a swimming pool. I have...
  37. B

    Earth Electrode Testing

    I have been tasked with carrying out some earth electrode and LPS testing using the fall of potential method but to do this I need to know the length of the rod. How do I work this out if I don't know the length?
  38. F

    Domestic Calculating Voltage Drop on a Ring main

    Hi Guys, I'm fairly new to the industry and have sat and passed all the relevant exams to become a Domestic installer. I'm a little stuck with one of my pieces to be assessed by NICEIC. I'm doing a full rewire at my dads house and would like to check that I'm calculating the cable volt drop...
  39. R

    3 phase Conveyor drum motor?

    Hi guys, anyone know where I can source a new 3 phase conveyor drum with quick deliver? thanks
  40. J

    Parallel Feeds

    Doing an EICR on a building and a sub board has two 4mm twin and earths feeding it. Cables are connected into same breaker in main db but take different routes to get to sub board. Is there anything in the regs regarding as I cant find anything. Cheers for any information or advice.
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