Borrowed Neutrals & Old Lighting Circuits

How the borrowed or shared neutral usually occurs on older lighting circuits, with a light fixture connected to line from one circuit and neutral from another.
This arrangement is NOT permitted, however can still be found in older properties, usually those from the 1960s / 1970s.
Previous video: kzbin.info/www/bejne/f3PGqGWAf9h4gtU

[@PJB71]

One of the best explanations of borrowed neutrals.

[@2BMIKE1569]

Very well presented video explaining why I have this exact set up between my hallway light and a light outside with a switch for that 3 feet away. Thank you 👍🏻

[@anthyatt6904]

I've just discovered this in my house (built in the sixties) and wondered what was going on. Thanks for the clear explanation and potential remediation.

[@vikingofengland]

Thanks again for a great video and explanation. I have discovered recently that I might have this situation with some 70's wiring in my house and this video confirmed exactly that.

[@Taizerable]

Very helpful. This was the exact situation I found on my property. Thanks.

[@PlasmaDan]

This is what my house wiring was like until I replaced it all last year. I remember trying to isolate the upstairs lights only to find the landing light was still powered. I found the link wire in the downstairs switch. Pretty-much everything was wired in single cable, the only T+E I found was some old lead-sheathed stuff for some of the sockets. Needless to say I ended-up replacing the entire house wiring.

[@piercebales9546]

I was called in to troubleshoot after a non-electrician who was charging $100.00 an hour failed to find the fault. A light had 20 volts to the switch and there were a number of circuits with joined neutrals. The problem was solved when all neutrals were confined to their own circuits.

[@brotheradam]

hmm...I always have placed the stairs and hallway lights on a separate circuit from the rest of the lighting anyway... but was trained by an engineer in the usa in his buildings... we put every building lights into bedroom circuits, bathroom lighting and then hallway and stairs lighting, and then we used common or kitchen and living lighting... for all of his properties... so that he could have the hallway and stairs lighting covered by a UPS system in case of storms or power outages... Guess I never thought about combining them because the extra 15 amp breaker was never really a problem in the boxes, and was easy to then place into an emergency power system. Now I actually set up a small box beside the main breaker panel for emergency circuits to lighting, fridge, and freezer, and one small set of outlets, usually in a hallway, in any system I wire in the caribbean, just for the use of a generator... means a bit more in costs but makes it easier in storms.

[@jackmcdalter3882]

Very informative, thanks. It seems to be as a much a case for borrowed live as a borrowed neutral.

[@gyrgrls]

Borrowed neutrals are fine if you like living on borrowed time. :)

[@michaelredman3840]

Whenever I have problems with insomnia I put one of your videos on.

[@stephenoflaherty5656]

Exactly the problem I found myself with. Thanks

[@pjeaton58]

On fitting a RCD consumer unit, some year ago, I discovered a wall light with the neutral "borrowed" from the ring main - you can imagine the effect !!!

[@TheChipmunk2008]

click?

[@benjaminxjones]

Spur cut into ring ?

[@Pmet14]

Brilliant explanation

[@markyy3590]

brilliantly explained.

[@carolinacurse]

Another very well explained video. Thank you!

[@tavislucaso]

I came across one on the same circuit once, someone obviously couldn’t get a link when they rewired (3 plate to 2plate wiring) so they took it off one of the kitchen lights. Client wouldn’t let me do damage so I consulted my boss who said although not ideal if it is within the same circuit and no others then it is allowed but should be mentioned on the testing sheet for future work.

[@coralbay00]

Subscribed after watching a few of your uploads. Had a unusual and one might say unorthodox situation with switch wire taken to the intermediate switch. Also the mains was taken to the wall switches throughout. Scratched my head at first but naturally soon got 💡 Could be an interesting one for you to educate on. 🤝

[@allantucker9681]

very very information this proves my electrician is at fault with alteraration and not existing wiring

[@kesgreen4639]

I had an odd issue at my parents' house. The bathroom basin taps were giving them a shock. Testing them revealed a voltage (luckily not 240!). I eventually traced it to a problem with the switch controlling the upstairs hall light from downstairs. I decided to disconnect it completely. The upstairs hall light is now switched by a motion sensor connected to the upstairs circuit only.

[@PerMejdal]

Having 2 different circuits in the same switch seems like a bad idear. If someone wants to service the switch he/she might only turn off one of the circuits, and get shocked. In Denmark you are required to put a warning on any box with multiple circuits.

[@TheChipmunk2008]

Per Mejdal Rasmussen Here I believe it's traditional to put a notice that says "Isolate all supplies" but not on domestic stuff

[@trueriver1950]

Yes: you have a dilemma: either you have two circuits in the same switch, or you have a live and neutral upstairs in the ceiling rose and that is also confusing if someone switches off the upstairs circuit and expected that upstairs rise to be isolated.

[@pcuser80]

Nice video Can you make a video about the differences in circuits from the us,uk and europe mainland? Thanks!

[@ianharrison6597]

Very good explanation. Thanks.

[@CITAP1]

It seems to have been common practice in the old days with Knob and Tube wiring. Connect things to the nearest Neutral.

[@vipinv8004]

very good information

[@lte7297]

Really useful, Thanks

[@brianoneill350]

Great explanation

[@johnstephens6974]

My house has a different system. The landing light is not connected to the upstairs at all but to the downstairs only. 2 way switching is achieved by the old method of 4 core cable, red, black, blue and yellow.

[@tedlahm5740]

Astonishing.

[@gassanali8667]

nice tutorial

[@azizahmedmuhammad4124]

Can you make a video about potential differences and high voltage imbalance between neutral and phase wires when the normal voltage 230 increases to more than 300 volt between any phase with neutral? The causes and solutions to this fault.

[@Takeithome345]

Great teaching !!!!!

[@james-reid]

Thanks for this great video, John. What should be done with the earth wire that comes down from upstairs? How should it be terminated?

[@daviddmf]

Great presentation thanks! Why is it called borrowed Neutrals when it appears it is borrowed Lines?

[@sbusweb]

Heres' an even more evil sneakier wire-saving-hack I could foresee being done in certain circumstances -- what about.. connecting a switches L1 and L2 terminals to line and netrual, the "C" (common) being a single-wire to one side of lamp, other side of lamp coming back to a similarly wired 2-way-switch ... Now you can have both neutrals borrowed at the same time with even less wires on the inbetween-cable =). The lamps' supply polarity will of course be different, and an apparently 'off' light can be live on both terminals, all sorts of evilness of that config! But I really really wonder if it has 'been done', somewhere out there!!

[@MrRetrotecchie]

This has been done many times and is in fact not uncommon in older properties in the USA!

[@turtmastert3545]

In the us it was known as the "Carter" system

[@Sparky-ww5re]

I've heard of this, and known it as a farmers 3 way or barnyard 3 way, since it allowed a yardlight between a house and outbuilding to be switched from both locations and have receptacles in the outbuilding constant hot using just 3 wires in between instead of 4, not counting a ground. As late as the 1960s, many old timers who lived through the depression era used this setup because it saved one wire, and they were very frugal and watched every penny spent on labor and material.

[@KazKasozi]

This still happens with a lot of houses in Uganda.

[@kida7591]

thank you

[@guybegroovin2666]

Thanks

[@andljoy]

How does this work if you have a 2 way switch upstairs and downstairs ? Our hall is like that and you can control the upstairs hall and downstairs hall from both sides. I play i safe and turn of both if i am working on it .

[@jwflame]

+Andrew Joy If there are separate circuits for up/down, the switch would contain live wires from 2 circuits, so both would need to be isolated before working on it. That is permitted, however 2 separate circuits being connected together is not.

[@green2489]

Hi John, Do you know a way of fault finding at the CCU to find out which light has the borrowed neutral? For instance if you were in a 3 bedroom house with a ground floor and a 1st floor: If you suspect it's the landing light would you take all the lamps out of the ground floor and 1st floor except for the landing lamp and then do continuity test with a meter tester between Line and Neutrals could you confirm it's the landing light? So if you supect it's the ground floor hallway you would remove all the lamps apart from the ground floor hallway, and so on. I've tried drawing it but I can't quite prove my theory!

[@0nezero]

Hi, I am a new electrician. A few days ago, I took power from existing cable to power store room light. I used junction box, but when I turn the light on the living room, light stays on regardless button on or off. I am confused any help.

[@jwflame]

Could be many things, but suggest you check that the cable is actually power, and not the switch cable for another light.

[@williamhaines7752]

I. Used to see 14/2 used all the time for travelers nd they pull a neutral hap hazardly out any circuit y that closes to the switch closes to the light .of cource using 14/3 is the correct way now days both switches Ares supposed to have a neutral contained in the box

[@DigBipper188]

I think you have an audio syncing issue here, JW...

[@MrAz85501]

What if the "borrowed" neutral is on the same circuit but hot and neutral are fed from different locations?

[@68LeCoq]

Hi John I have question: how to identify opposite legs of conductors in the existing socket circuit for the continuity ring test ?Thanks JAN

[@trueriver1950]

Around 6:30 and again 10:30. This might not have been a cheat at the time of installation. Up to the sixties or maybe the seventies it was usual to have just one lighting circuit for a small house. This means that it was apparently legitimate to wire it the "lazy" way. Then later on, the upstairs and downstairs lighting circuits are split for whatever reason, but not entirely rewired. At that time whoever does that work fails to notice that the light at the top of the stairs runs from the downstairs live but returns via the upstairs neutral. The illegal wiring therefore comes from not surveying the original properly before the lighting circuits are split apart. Yes it's still sloppy work but the sloppiness occurred rather later than the date of the original wiring. My guess (and it is only a guess) is that this is the more usual history of these borrowed neutrals

[@jagannathnayak6387]

How much two way switch need How to sharing and borrowing I could not understand the phenomenon

[@diprobase1000]

can you do a video on 3 phase cheers

[@arronnorton3072]

Hi I have 2 twin core and earth and 2 1core with an earth in ceiling rose a pull core and switch in room with the switched live being a single core and earth can you explain how this type work thanks

[@allantucker9681]

i rencenctly had a shower installed alongside a new light fitting and fan. Since then the breaker for the upstairs lighting every so often trips now i can turn breaker on and light only go out when i turn downstairs lights on. Could this be a neutral fault because the kanding light is fed via groud floor and the neutral is 1st any ideas

[@ronplucksstrings7112]

...more "creative wiring" to save a single wire...again, retrofitting or upgrading, and running a cable between downstairs and upstairs for the purpose of creating a two-way control of a light, running a three conductor cable prevents all of this unnecessary complexity and creating potential safety hazards. Not to mention multiple circuits in a single box... Question: Did the British brainiacs who came up with these ideas also work for Lucas? Edit: I don't normally badmouth an otherwise good, informative presentation by a guy who clearly knows of what he speaks (I don't even know how I got here!)...but that's why we have the National Electrical Code in the US...to prevent "creative wiring"...which might work, but which also creates unusual or unsafe conditions ready to bite someone in the future!

[@kaleighbates101]

Ronplucksstrings aaa

[@LectronCircuits]

Wire a dozen 24V halogen lamps throughout the house, all connected in series. Problem solved. Cheers!

[@geoden]

Not very clever! Lets say ONE of your lamps fails, then ALL your lamps go out! You are now faced with the problem of finding which one failed!

[@calmeilles]

@@geoden The old Christmas tree lights game. :)

[@brianhewitt8618]

👌

[@zerosparky9510]

Seen it on jobs before.

[@reggiebacci]

You've gotta wonder how often someone couldn't be bothered to obtain proper three core, and thought sod it, we'll use twin & earth with the "earth" as one of the switched lines... Or neutral... Or any other combination thereof. Scary thought.

[@TheChipmunk2008]

reggiebacci I have come across that recently actually... someone wanted to install an extra light switch in a box that had ONE twin and earth, they used the red as the phase feed, then earth as the switch leg out of the other switch (for an outside light). Because the cable was plastered in. I chased a new TC&E into the wall for him, and put it in proper oval conduit so it can be re-threaded at any future time.

[@sbusweb]

+reggiebacci Indeed that is quite evil!

[@trueriver1950]

I've seen that. I moved into a property where a slightly damp passage way through a row of garages had been wired with T+E, using the bare earth as the Live, and the L & N as the two SL. In metal cased switch boxes. Slightly damp walls and no earth. Was alerted when the metal switch box felt "soapy" while I was looking at the property prior to purchase. I bought it anyway but did a very urgent rewire of the DIY passage lighting the day after I legally owned it.

[@tangoterrier]

I am confused. Aren't all the neutral wires connected back to a common bus bar?

[@trueriver1950]

Problem arises when the neutral becomes disconnected or broken. The broken end away from the CU floats up to 230V as soon as any lamp is turned on. So you come in to mend it, turn off the downstairs circuit, and get zapped by the power still being fed from the upstairs live. That's just one reason to ALWAYS poke with a test screwdriver, it's less painful than finding out the other way

[@jameshansing5396]

Which test would show up this situation?

[@jwflame]

Leaving the lamps in on both circuits, switching the light switches on, and testing between the conductors of the two separate circuits at the consumer unit.

[@jameshansing5396]

@@jwflame so something you’d have to be specifically looking for? Would it show up on a standard EICR?

[@goldenboy5500]

I gather wiring is in single phase 240V in most homes in the UK

[@jwflame]

+Richard Golden-DeWitt Yes, in virtually all of them. 3 phase 400V is available but normally only installed in commercial premises.

[@goldenboy5500]

+John Ward I'm finding this quite interesting I have always known the UK was 240V it's done so much different here in the US & in Canada virtually every home here is 2 phase 110V-N-110V and 220V across the load lines also what you call a RCD we call them GFCI and most of the time are located at the outlet, mostly used at wet areas

[@TheChipmunk2008]

Yes, the outlet style GFCI seems to be very popular in North America... whereas we go for them at the board (electrical panel). Does the same job though, which is the important bit :)

[@the_real_hislordship]

John Ward Interesting. Here in South Africa it can be single or three phase for homes. I have three phase for a larger house, but also the 400v feed is great for a borehole pump to water the garden.

[@trueriver1950]

Yes. Normal practice is adjacent houses are on different phases to keep the unbalanced return current down as far as possible. Imagine the surprise when DIY dimwitted thieves connect the live from their neighbour's house to their own to steal power through their neighbour's meter, then don't realise they need to turn their own power of first... Notice that although each phase is 230V, the difference between phases is just over 400V and they basically shorted them together ... Two company fuses and a visit from the police later ... --- I'm currently in a three floor walk up, and my neighbours vertically are all on the same phase as me, but next door horizontally each way are on different phases. That's because the flats are wired on vertical single phase cables that daisy chain to the the three company fuses on the way up

[@coralbay00]

Pet hate 🤦‍♂️

[@Flapjackbatter]

aaah ! Ok.

[@johnmac8084]

I'm confused, from about 6:10 isn't this borrowing a live, rather than a neutral? Each circuit has it's own neutral, but the live link in the switch shares the downstairs live with upstairs?

[@jwflame]

It can be considered that way, although it's normally called borrowed neutral. Regardless of name, it's taking live from one circuit and neutral from a different one.

[@johnmac8084]

Well, yes, I guess it's the flip side of the same coin really, you still end up with the same problem, i.e. a circuit that should be dead that isn't

[@muhammedabbas242]

Well, both names are true ... But it is more sensable to consider this case a "borrowed neutral" rather than a "borrowed live line" ... When a load is connected to a live line of a circuit it is considered within that circuit (even if it doesn't complete its circuit with a neutral line) cause it will be active and dangerous all the time the circuit being energized. I guess that's why the common name is "borrowed neutrals". B. R.

[@johnhenry4113]

Not good. Bad practice.

[@ifyougetstucklookitup237]

Thank you.

[@KazKasozi]

This still happens with a lot of houses in Uganda.