# circuits

1. ### Power Calculations in Circuits | Electrical Training Video

This video explains power calculations in circuits and how to use the calculations. Trainee Electricians studying for qualifications such as NVQs and other electrical courses may find this helpful.
2. ### Electrical Circuit Components Overview

Easy to understand video lesson in Electrical Circuit Components. Provides a good overview of components including the resistor, capacitor, inductor, transistor, diode and transformer. A good source of information for Electrical Trainees on NVQs and other courses.
3. ### Number of Conduits run and number of circuits

I am in estimation and often estimate conduits run in the drawings. My clarity about number of conduits run is not good. I want to know that in multiple circuits zone, how we calculate number of conduits run to the panel. For example. If i run conduits from Ckt A-1 to ckt A-2, i need Two number...
4. ### Recording of 3-Phase Circuits

Hi all! So, I was filling out a test sheet for a number of 3-phase circuits we did an EICR on. For years whenever a 3-phase circuit exists I have recorded them on a single line (eg. 1/TP or 1/L123) and recorded the highest or lowest value applicable to that particular test regardless of...
5. ### Dual board with no earth on final circuits

Hi guys. Need to change the fuseboard at my parents house but none of their final circuits have a cpc run to them. Obviously have an earth on the main incoming so I can get a 16mm earthing conductor up to my new 18th edition metallic consumer unit but they don’t want a rewire so none of the...
6. ### Extending ring final circuits

Hi. I have a CU move to do - around 5m from current location. There are 10 circuits, 4 of them ring finals. I'm considering whether to extend the rings 'as are', or to split the rings somewhere in their approximate middles and extend them to separate RCBOs as radials, the aim being to reduce...
7. ### RCD tripping under high load on 2 circuits

I’m in desperate need of someone with great fault finding knowledge. I have a dual rcd consumer unit as seen in picture. The left hand side rcd trips when anything with a high output like a tv for example is turned on in any sockets protected by the left rcd. The left rcd also trips when trying...
8. ### Domestic 3p breaker feeding 3 x 1p circuits

Hi everyone. I may be blind but I can't find a definitive answer. Can I use a 3 pole breaker (originally feeding a massive 3 phase heater) to feed 3 single phase circuits? I've run seperate neutrals for the 3 new circuits and the breaker is rated for the load required - 30a per phase (I'd...
9. ### Cooker circuits fusing down ???

Hello I’ve pulled out a electric oven and the connection plate at the back for the cooker circuit has 2.5mm hardwired to the 6mm circuit for a 1.76kw load and also a 6mm connecting a induction hob,unknown load. Does the 2.5mm need to be fused down or is it okay being spurred off the cooker...
10. ### Domestic 10mA RCD for bathroom circuits

Been to look at a job this morning for a CU change, customer the type who wants to have his say on every tiny detail. He has already bought the CU as well, a Wylex RCBO unit..... I pointed out that the RCBO ratings he has bought don't align with what I actually need...and that some will need...
11. ### I never install ring circuits, the potential for danger is unacceptable

I’d like to know if anyone else here refuses to install ring circuits in domestic premises. For me it’s either a 20a radial / tree circuit with 2.5mm, or a 32 radial / tree circuit with 4.0mm. Frankly I’m tired of finding broken ring circuits on 32a CB’s, as well as mismatches on end to end...
12. ### Bunches up lighting circuits

Good morning all! Currently carrying out an EICR on a commercial property and have noticed 8 lighting circuits bunched into 2 MCB’s. 0-EE74-FE0-F729-4048-A7-F4-2979-EBDFD688 - https://ibb.co/hCTKpsC No real danger but not very practical as nuisance tripping could occur and the labelling is a...
13. ### Supply and final circuits for stables.

Hi all, just looking for advice prior to a potential upcoming project supply stables for horses. The supply characteristics into the main house is TNCS and the stables are located approx 40m away from the building. I am thinking of putting a 1w non-rcd protected consumer unit at supply end...
14. ### EICR every 3 years for EM light circuits

Evening all Got an email from a prison we do work at who said they have been told that any circuits that contain emergency lights need to periodically tested every 3 years on top of the 5 yearly test. I have looked through the IET but cant see any info on it? Can anyone point me in the right...
15. ### New circuits wired into a plastic consumer unit

Had to install a ring main & cooker circuit for a new kitchen we have been doing. The consumer unit is hager split load but is plastic. There is no room in the cupboard to add another board and the customers dont want to pay for a board change. I guess i could just note on the form saying...
16. ### How to test a circuits in steel conduit as the cpc

Good evening I am currently a training to become an electrician. I do hold both initial verification and periodic testing qualifications however this is an issue I have never personally had to deal with and was never mentioned on any of my courses as often seems to be the case. Basically I am...
17. ### What if a circuits Max Zs is exceeded but the circuit is protected by an RCD?

Just processing an EICR and noticed a couple of final circuits measured Zs values (fed from a sub distribution board) slightly exceed the Max permitted Zs values for the OCPDs that protect them. Obviously I will note this as a design flaw in the observations, but I just wondered, from the...
18. ### Additional CU in Garage for Two Circuits?

Hi We live in a new build (2015) and the developer added Power and Lighting to the garage via a double socket (spur from house) and then a single light coming off the socket (via FS) for the garage. I then added another driveway floodlight off another FS. Anyway, we plan to do some garden work...
19. ### 1x swa to do 2x circuits

Looked at a job for a old boy- and wanted to keep costs down for him and make my job bit neater/simplier Job is to get new swa from new little rcbo board inside house to a external ip65 light switch and then into 6x external lights then he also wants to power his little shed at end of garden...
20. ### Shower and cooker circuits

Hello I'm an apprentice but don't do any domestic work just commercial and industrial atm. My question is if you don't have a design current for shower or cooker e.g. customer doesn't know what they are buying yet, how do you select your cable sizes and mcb rating? This is purely for learning...
21. ### Two ovens - how many circuits?

I'm planning to get two single ovens and have been trying to find the best way to do the circuits. People seem to do it every way possible but I have doubts about some of the ways that they are done. The ovens I'm looking at are 16A appliances (max power is approx 14A), so I won't be plugging...
22. ### Timers on LED Lighting Circuits

Given the demand for low energy lighting in new build/major extensions it seems that the LED technology leads the supporting equipment such as dimmers and timers. The problem I have is that a client wants to put all the lights on each of four circuits on a 24/7 timer for security purposes (each...
23. ### Random RCD trip & interconnected circuits. Suggestions appreciated.

Hi There, I was called out to a house RCD trip which would not reset. An old style 10 way split board with a single 30 ma RCD (half without RCD protection). RCD checks out fine but I found a faulty chandelier & replaced it with a single bulb for now. Also a faulty 12v transformer flickering; now...
24. ### Adding RCD protection to existing circuits

Here’s a commercial scenario for you to comment on over you nightly dram. So there is an existing consumer unit with older style MCBs or bs88 fuses. RCBOs cannot be added to existing and customer wont pay for a new consumer unit. My soloution is to add a garage unit onto the side. Remove...
25. ### Best way to add Garage circuits

Hi, I am a keen DIYer (dangerous phrase - I know) but will NOT be doing this work myself and will be getting a local sparky (Part P etc) in. However I'd like some advice as I want to check its the best way of doing things. I have a Tenby split load Consumer Unit (circa 2005) in the Garage with...
26. ### Wiring 2 lighting circuits using one 6 terminal junction box

Hi there, my name is Paul and I'm currently studying towards a city and guilds level 2 electrical installation, we are currently on lighting circuits for our practical, we have been given a task to wire up 2 lighting circuits using a 6 terminal hager junction box, I'm ok with wiring one circuit...
27. ### Cooker circuit options

Just finishing a rewire, customer not sure on hob and cooker at design stage so I went for 2 circuits with 6mm withe 2 32amp rcbo's. Hob and cooker 5 meters apart. Now induction hob and oven have arrived onsite and both suggest a 13amp supply is suffice. Should I downgrade the rcbo's to...
28. S

### Two 'Circuits' in one MCB

Can't find the recent thread about this, but I've been looking at smoke detectors and got this from AICO under System Installation: "• The supply for the mains powered alarms shall be taken from an electrically protected, regularly used local lighting circuit at the nearest source except for...
29. ### 2 external lighting circuits fed through 1 SWA cable

Evening, Although I cannot see a specific regulation can anyone come up with a reason why someone could not run 2 line and 2 neutrals with both circuits fed from the steel wire? To verify this would feed 2 number lighting circuits down one path, but I.e 1No 5 core swa. From a cost point of...
30. ### Contactor issues on ceiling heater circuits

Hi I looked at a contactor schneider ict 4 pole 400v 25a. The fault was a loud knocking noise coming from the electricial riser cupboard. I suspected one of the contactors was pulling in and out rapidly (this known as chattering?) I am hoping you can point me in a direction as I'm not...
31. ### Outside light fed from 2 circuits

I went to a small job today to change a sensor for an outside light. I expected it to be straight forward. I started by isolating the supply, which ended up taking longer than expected as it needed 2 circuit breakers to be off in order to isolate it. I explained that i would need to remedy...
32. ### Outdoor Heating, Blind Motors, New Circuits - Brain hurts!

So, with the house job nearly completed, the wife wants some outside heating and the blind man needs to connect his motors for the new outside blinds coming... HEATER She’s found a 2kw infra red heater that, while I’m not keen on trailing cables on the deck will probably do the job if it’s...
33. ### Dimmers on two way switched lighting circuits?

I've installed a number of dimmable LED downlights switched two ways. They're switched by one dimmer and a standard rocker. When they are switched on with the dimmer the lights operate normally and can be dimmed however they seem to override the other switch which will not switch the lights off...
34. ### Swa 4core cable used as two 2core circuits

Working on a job have found a 4core cable going into a weather proof box and splitting up into 2 circuits again at the board it split in two single phase MCB s . My question is would you judge the current carring capacity of the cable as a two wire or four wire
35. ### No pics sorry............

Went to view a kitchen refit this week, new kitchen and new rfc circuit dedicated to the kitchen, have a look at the CU and whilst inspecting I see that the 2 lighting circuits, up & down, are both wired with the same 1mm 3&E cable (pre 2005 cable) Red as line to down mcb, yellow to up mcb...
36. ### Calculating Voltage Drop On Lighting Circuits

Hello All, I should know this and have been avoiding asking but just want to be sure. So I am designing a downstairs lighting circuit for a domestic refurb/rewire. I reckon max demand will never hit 3 amps. So using the basic formula for voltage drop - (tabulated value x design current x...
37. ### Adding new circuits to all insulated consumer units

hi guys, Is it still ok to add a new circuit to an all insulated consumer unit in a domestic dwelling. I only ask as my previous employer always changed consumer units for metal when adding a circuit. I know this is probably a stupid question. Thanks for replies
38. ### Oven and cooker circuits

Hi i have a double oven which is 5.8kw and induction hob which is 7.4kw there currently isnt a cooker circuit in the house but there is 2 spaces in the CU so am I correct in thinking I can put 2x32A breakers in and run 6mm cable to both .
39. ### Splitting 3-phase circuits for 3 high draw theater fixtures.

Hello. I'm new here so my apologies if this post ended up in the wrong forum. I have a basic understanding of phases and voltage and the lot. Today I'm trying to wrap my head around how I might be able to split one 3-phase 240v 50a source to accommodate 3 high draw theater fixtures. Here's...
40. ### Lighting circuits and possible cross-over

Hello. I have a possible issue with the lighting circuits in my house. There are two lighting CCTs: Dropbox - 01.JPG - https://www.dropbox.com/s/ike2aygjja64pfm/01.JPG?dl=0 1 LIGHTS supplies: Lounge Kitchen Downstairs toilet 2 LIGHTS spplies: Hall Upstairs landing Upstairs bedroom Upstairs...

## Are there enough independent certification companies?

• ### No

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