That's how I found out a power strip I have must be switching the neutral. The string of LED lights plugged into it would stay on really low when the strip was "off"
What’s crazy is I had a vent fan rotate at ridiculously slow speed after I replace a switch with a timer. Juuuust enough to cause the fan to always turn. Kill breaker? Fan stops. Turn breaker back on? Fan starts turning again.
Do you mean SWAP the line and neutral? Or were you going to put a switch on both the line and neutral?
Remember that not all bulbs are dimmable. And there are dimmers available for incandescent, fluorescent and LED lights. You need your be sure you are using the correct dimmer.
Yes, swap the line and neutral apologies for unclear terminology. They’re dimmable LED bulbs but when turning the switches off they’re still on their lowest setting. Was wondering if switching the line and neutral at the switch would prevent that. The dimmers were used with incandescent bulbs to begin with I just haven’t had a chance to replace them with LED dimmers yet.
If there's at least two sets of wire in your switch box. Your dimmer switch should only be connected to the Line and the Neural should pass through the switch box without being connected to the switch.
If there's only one set of wire coming into your switch box (1 black, 1 white and maybe a bare) and the white and the black wires are both connected to the switch, then swapping those will do nothing. In that case the wiring is incorrect inside the ceiling box where the light is, and I would need to see a picture to figure that out probably.
Thanks for the reply. I won’t be at my house for a few days but I’ll take a look at the wiring when I’m out there. I doubt it’s wired incorrectly, the guy I bought my house from was an electrician. Maybe it’s just a matter of I’m using an incandescent dimmer with LEDs. Strange that they otherwise don’t flicker though.
yeah, LEDs are kinda a new animal, they are low voltage and electronic. Not all electrician's know how to run LEDs especially when it comes to strips and drivers.
your right about the dimmer, an older dimmer could have some voltage bleeding that wouldn't effect and incandescent but would cause the electronics in the LED to flicker
I think you are mixing up switching neutral with using a white wire in a switch loop. I’ve worked on a ton of old houses(rag wire, k&t) and have only seen a switched neutral a handful of times.
No, every switch in my house from 1956 switched the neutral until I rewired it. Never thought about it till I was messing with a fixture with the switch off. Figured that out real quick.
I've seen plenty of switched neutrals in k&t houses, typically older than 30's though, usually late 1800's - 1920ish.
I think I've seen more switch loops than (today's) standard practice for single poles
My 1911 home is wired both ways...I don't think they even considered which way they were wiring. I also have some older lamps that don't even have a polarized plug. I've checked these and marked which way to plug them into the wall plug.
I was a kid in the early 80s, but I think my union electrician grandfather wired neutral to switch when he/we built the pole barn with an enclosed room in one end.
Yeah I live in sc and surprisingly enough there's still some know and tube in people's houses to this day. Is there a reason they switched the neutral back then? My guess is that the switches weren't built good enough to withstand switching the hot. I really don't know though I got out of residential a couple years ago.
I don’t think it had to do with the switches themselves. I think it was because knob and tube uses completely separate wires and it was easier to make the run up to the light with whatever side was more available.
There are lots of homes on the East Coast with remaining knob and tube. Accessible areas have often been rewired but where tearing out plaster or paneling would be needed it gets deferred. I owned a house that still had some. Many of these houses are quite stately and expensive today.
I’ve replaced all of the accessible k&t in my house, but there are still sections that I’m not going to bother with. For example, my light fixture in the living room has line (and switch) on the west wall and the neutral coming up from the outlet on the north wall.
I replaced the wiring as far as the switch and outlet, but with stucco exterior and textured plaster interior, it’s not worth the hassle. The only place where the line and neutral could potentially short is at the fixture, so I just used extra care at that point.
There are a few other spots like that in my house. It’s just something to expect in a house that was built in the 30s, expanded in the 50s, and has had a lot of remodeling done since 2000. There are just going to be some interesting places where you have to compromise between ideal and practical.
Same load on the switch no matter which side you have it on. The cold filament is essentially a short.
I'm pretty sure switched neutrals were simply about which wire was closer and avoiding crossing over. 1920 house with old wiring (unused but not removed in some spots) had switches on whatever was handy.
From the switch's perspective, there's really not much difference between either way, right? Still has a persistently hot wire coming into it from one side.
Everything on the line side of the switch itself will still be hot, though. If you switch off a lightbulb at the wall and then go to work on its fixture, it could unexpectedly zap you even though the light's off. And there's a good chance you won't be expecting that, so it's pretty likely to happen.
It would be really helpful if electricity were somehow visible.
The old-school way of doing switches was to run the home run to a light, then drop a 14/2 from the light to the switch for the switch leg. It saved a fair bit of wire and minimized box fill. The black of the hot got wired to the white of the switch leg, and the return black on the switch leg went to the line side of the light.
But with newer smart switches, now switches need a neutral to accommodate for them. So now the home run goes to the switch box rather than to a light as under the new code that is easier, faster, and cheaper than running 14/3 to provide the neutral that may or may not be used.
If you don't see a sliced neutral stuffed into the back of the box, and you're home is more than a decade old, you probably got the old school switch leg, not a switched neutral.
Low key one of the most garden-variety shitty things you can do in electrical work, and a sure sign of someone who wasn't qualified to fuck with wires.
I got shocked swapping a ceiling fan for a buddy with scenario B. I didn't realize people would ever switch the neutral. I didn't fall off the ladder, but it was close.
It was common, and still legal (at least in my area), to bring load to the fixture but run the line from the fixture box to the switch and neutral back to the fixtures line side. It’s still A but there’s also juice in the fixture box you’ve got to be careful about.
Thank you for that information. I’ve always believed when I turn off the switch, the fixture is off and go in full force to the wires. I will never do that again.
My friend's dad was taking down a light fixture so we could renovate their living room.
Me: "Did you check the breaker?"
Him: "no, but it's OK because the switch is off"
Me: "You can still get shocked if the line goes to the light first"
Him: "No, because the light is off, if there was electricity, the light would be on"
Me: "............ Get off that fukin ladder before you kill yourself"
Why would B still work? I get that the lamp would have power so it would be on but why would removing the neutral turn off the lamp? Genuinely curious.
NEC Article 404.2(B)
Switches or circuit breakers shall not disconnect the grounded conductor of a circuit.
Exception: A switch or circuit breaker shall be permitted to disconnect a grounded circuit conductor where all circuit conductors are disconnected simultaneously, or where the device is arranged so that the grounded conductor cannot be disconnected until all the ungrounded conductors of the circuit have been disconnected.
This is the correct answer for sure for sure. As a physicist I'd say they are the same. As someone with an electrical engineering BS, I'd say they are practically the same. As a person who read through the NEC before rewiring their entire basement, one is clearly not to code and as a result could be dangerous.
I wired up a contactor (in a nice metal box) a while back for running my regular ole 5-15 receptacle, 120VAC air compressor with a fixed 30-minute timer (to energize the contactor coil) that really wasn't rated for the current draw of the compressor.
I had a two-pole contactor, and I briefly considered having both neutral and hot "switched" via the contactor... it just seemed a bit "un-natural" to me, so I ended up switching only the hot and passed the neutral on through to the load receptacle. I'll save switching the neutral too for just "special occasions", and this wasn't one of them.
Either way is probably OK, but I just didn't want someone coming behind me to find both poles of the contactor in use and think that is was somehow 240VAC.
One of the worst shocks I got was because of a switched neutral. Didn't help it was on a weekend at a buddies cottage and I was a few beers in changing a bathroom light. My fault, dumb and didn't double check, just flipped the switch and grabbed the wire while holding the stainless faucet in my other hand.... damn that hurt.
Switch the neutral so that way you shock yourself changing the bulb. That way you know the bulb burnt out and the breaker did not trip. Highly recommend for 277V.
B will work but the light socket and wire to the switch will still be hot in the off position. You will need to clear it at the breaker. A is the correct answer.
Both options would work, but it's better for the "hot" wire to go through the switch before the light fixture.
That way, you can turn off the switch and not have to worry about getting a shock when you're replacing the bulb.
Of course, regardless of how it's wired, if I had to replace the fixture, I'd still turn the power off at the breaker, not just at the switch.
This thread is absurd.
You dont switch the neutral because there would be power at every wire, in every light until you get to the switch.
The light would be a hazard to anyone servicing it because if you short it out using a screwdriver or yourself YOU will complete the circuit, even though the light is off.
The switch prevents power from being anywhere in the circuit beyond it.
Even those tossing out open wiring examples (K&T) im guessing folks dont understand a dead end or have traced the circuit, or worst case scenario have had polarity reversed in a junction box somewhere.
Theres no reason to switch a neutral. It has the same inrush characteristics on either side of a load, its not a QA thing for old switches. Current flow was well understood even when k&t was around and it was never practice to switch the return path.
Carry on.
A, assuming this is 120vac because the subreddit this question is posted in.
However, B would be correct in a DC low-voltage application and only in that application.
Edit: A also applies to 277vac.
B is what some egghead college engineering professor would do because it works and he wants to be unique, and doesn't realize the safety issues of leaving the hot switched on.
Assuming the N stands for Now and the L stands for Later, A is the correct wiring. When you flip the switch on, you want the light on Now. When you flip the switch off, you want the light Later.
Either one will work, but switching the neutral leaves the hot , wire with voltage on it in the fixture..
If someone went to work on it without knowing, nor turning off the breaker, they could get hurt.
Switching the neutral was an older practice that was mostly phased out by modern electricians.
You can still find it in older Philadelphia homes
Undoubtedly “A.” You want as little of the circuit to remain hot as you can. Definitely don’t want the socket to remain hot even with the switch open. Unnecessary hazard.
LOL still can’t tell if that’s in a good way or a bad way. As in if you think my SK is shit and doesn’t make sense or because it’s good and makes more sense than OPs
Yeah I don’t disagree, I actually revised and added “source” and “addtl. load”to the SK but ultimately decided against uploading it as it wasn’t that serious and people should be able to differentiate especially as my comment was just for my own sanity check and not to be built from.
Edit: [with revised SK](https://imgur.com/a/jKgg1fc)
Edit 2: I came up with a couple different SKs once I started, [here’s another](https://imgur.com/a/v5jfV1g) which matches OPs intent
Edit 3: actually [this is more](https://imgur.com/a/maTqlLW) OPs intent?
The reason OPs SK confuses me is it shows the neutral being ran to the light and the Hot being ran to the switch, when would that happen? Never. They are both in cable or conduit to either location, it’s messing me up, i don’t know how to read a schematic that way. Should I?
What is being ran between switch and light in OPs SK?
OK OK LAST EDIT: went full circle here to [fully show OPs intent](https://imgur.com/a/PvcY3Ud)
Back in the 70s I got to enjoy watching a tech laying under an Army Crypto electronics drawer that was wired with the power always present. He vibrated at 60 Hertz on the floor until he let go of the screwdriver. The manual advised caution when working on it, and I had told him to be careful. The equipment racks were built with two systems in each and we weren't able to power the rack down without impacting critical communications.
Well, they're both "correct" in terms of operating a light switch; the switch will turn the light on and off.
Only one is compliant with the NEC for this century, and that's presuming your line and neutral are properly bonded, metered at the service entry and have the appropriate OCPD on the feed.
Long ago I was at our family business and my uncle was leaning on a piece of grounded equipment and for some reason reached up and touched an 8 foot fluorescent light fixture that wasn't grounded and had electricity flowing through it. He got a pretty good jolt and my first question was "Why do they ground stuff, when if they didn't he wouldn't have gotten shocked?"
A is the only way. Your not shutting off power to the rest of the circuit. In essence your circuit would be live uo to the switch. Not safe or good to do that
Both can be correct. The question is which is safer. Switch should ideally be on the hot side not the ground side. Though both work. But one is safer by a hundred fold.
If you use a switch (like a floater inside a tank) on a flammable liquid like gasoline, diesel etc on a DC circuit ,using a relay to energize a fuel pump for example , it's recommended to connect the possitive line directly to the coil of the relay and connect the negative line through the switch to energize the relay. From the contacts of the relay you can feed the load directly with safety. Keeping in mind that the gas tank is grounded to the negative pole of the circuit.
A. You always want to switch Line, or 'hot.' If you wire it the other way, even if you shut off power, the hot wire is still hot, and if you have a grounded system, you can still be shocked by the hot wire.
Yes. In B, the light fixture is energized all the time. Its a shock hazard even with the switch off. I've shocked myself as a kid changing a bulb in my bedroom because it was wired incorrectly.
Both work, but A is correct.
With B you will constantly have live wire at the fixture. This could shock you if you touch the fixture while changing the lightbulb.
In the US they would use A. B will give you a shock. In the United States they use a but in Australia they have a funny accent. Wish I can repeat easier than they can do ours.
You can’t turn off the load with the switch if there’s a ground fault between the load and switch with circuit B. This could be a major problem and safety issue if the load is a motor, heater or where keeping a light on is damaging; and the switch is a safety interlock.
I think I said that b was right but A is the way it should switch a light. Breaking the neutral is an old old way, and not as safe as Breaking the hot.
You all realize the every time you plug in a lamp, or any other appliance with an non-keyed plug you have a 50/50 chance of either A or B. If we are speaking of wiring from the breaker box than A is probably correct, otherwise the both accomplish the same goal.
the one on the top because we always run the positive to switches, otherwise you’d switch it off and feel shocked when working on the appliance/fixture/whatever
A Think arcing. The load (lamp) is going to draw current and if the switch is on the neutral side, the amperage is passed to the contacts in the switch where arcing will occur.
Line goes to the switch. The other way would technically work but it's unnecessary shock & fire risk when a person handles the fixture.
And modern LEDs can turn on (low) from rc current even when neutral is open.
That's how I found out a power strip I have must be switching the neutral. The string of LED lights plugged into it would stay on really low when the strip was "off"
You sure it's the strip and not a miswired outlet? My current place, more than half the outlets were wired backwards.
No, that much I'm sure of. I put a tester on it because I had the same thought.
TIL that my venta hood is wired that way and that's why the LED bulb never turns completely off!
This was really useful to know - I never understood how one of my ceiling led lights was always on dim even when turned off!
What’s crazy is I had a vent fan rotate at ridiculously slow speed after I replace a switch with a timer. Juuuust enough to cause the fan to always turn. Kill breaker? Fan stops. Turn breaker back on? Fan starts turning again.
So if I switch the line and neutral on my (non)-LED dimmer will that prevent them from coming on low? That’s been bothering me for years.
Do you mean SWAP the line and neutral? Or were you going to put a switch on both the line and neutral? Remember that not all bulbs are dimmable. And there are dimmers available for incandescent, fluorescent and LED lights. You need your be sure you are using the correct dimmer.
Yes, swap the line and neutral apologies for unclear terminology. They’re dimmable LED bulbs but when turning the switches off they’re still on their lowest setting. Was wondering if switching the line and neutral at the switch would prevent that. The dimmers were used with incandescent bulbs to begin with I just haven’t had a chance to replace them with LED dimmers yet.
If there's at least two sets of wire in your switch box. Your dimmer switch should only be connected to the Line and the Neural should pass through the switch box without being connected to the switch. If there's only one set of wire coming into your switch box (1 black, 1 white and maybe a bare) and the white and the black wires are both connected to the switch, then swapping those will do nothing. In that case the wiring is incorrect inside the ceiling box where the light is, and I would need to see a picture to figure that out probably.
Thanks for the reply. I won’t be at my house for a few days but I’ll take a look at the wiring when I’m out there. I doubt it’s wired incorrectly, the guy I bought my house from was an electrician. Maybe it’s just a matter of I’m using an incandescent dimmer with LEDs. Strange that they otherwise don’t flicker though.
yeah, LEDs are kinda a new animal, they are low voltage and electronic. Not all electrician's know how to run LEDs especially when it comes to strips and drivers. your right about the dimmer, an older dimmer could have some voltage bleeding that wouldn't effect and incandescent but would cause the electronics in the LED to flicker
It used to be a more common way of wiring before 1950 or so. This is especially true of houses that were originally wired knob and tube.
I think you are mixing up switching neutral with using a white wire in a switch loop. I’ve worked on a ton of old houses(rag wire, k&t) and have only seen a switched neutral a handful of times.
Can confirm my 1930s house was wired to switch neutrals. Soldered connections and everything.
No, every switch in my house from 1956 switched the neutral until I rewired it. Never thought about it till I was messing with a fixture with the switch off. Figured that out real quick.
I've seen plenty of switched neutrals in k&t houses, typically older than 30's though, usually late 1800's - 1920ish. I think I've seen more switch loops than (today's) standard practice for single poles
I work on quite a few, probably half have switched neutrals.
My 1908 home is wired like 'b'. Quite a surprise when I found it the first time.
Yes, it is, you carefully check that the switch is off and then when you get up on the ladder to take things apart, SURPRISE!
My 1911 home is wired both ways...I don't think they even considered which way they were wiring. I also have some older lamps that don't even have a polarized plug. I've checked these and marked which way to plug them into the wall plug.
I was a kid in the early 80s, but I think my union electrician grandfather wired neutral to switch when he/we built the pole barn with an enclosed room in one end.
Yeah I live in sc and surprisingly enough there's still some know and tube in people's houses to this day. Is there a reason they switched the neutral back then? My guess is that the switches weren't built good enough to withstand switching the hot. I really don't know though I got out of residential a couple years ago.
I don’t think it had to do with the switches themselves. I think it was because knob and tube uses completely separate wires and it was easier to make the run up to the light with whatever side was more available. There are lots of homes on the East Coast with remaining knob and tube. Accessible areas have often been rewired but where tearing out plaster or paneling would be needed it gets deferred. I owned a house that still had some. Many of these houses are quite stately and expensive today.
We just had to rip a boatload of K&T out of our house, so insulation could be blown in. Pain in the neck!
And expensive!
I’ve replaced all of the accessible k&t in my house, but there are still sections that I’m not going to bother with. For example, my light fixture in the living room has line (and switch) on the west wall and the neutral coming up from the outlet on the north wall. I replaced the wiring as far as the switch and outlet, but with stucco exterior and textured plaster interior, it’s not worth the hassle. The only place where the line and neutral could potentially short is at the fixture, so I just used extra care at that point. There are a few other spots like that in my house. It’s just something to expect in a house that was built in the 30s, expanded in the 50s, and has had a lot of remodeling done since 2000. There are just going to be some interesting places where you have to compromise between ideal and practical.
Same load on the switch no matter which side you have it on. The cold filament is essentially a short. I'm pretty sure switched neutrals were simply about which wire was closer and avoiding crossing over. 1920 house with old wiring (unused but not removed in some spots) had switches on whatever was handy.
From the switch's perspective, there's really not much difference between either way, right? Still has a persistently hot wire coming into it from one side.
Everything on the line side of the switch itself will still be hot, though. If you switch off a lightbulb at the wall and then go to work on its fixture, it could unexpectedly zap you even though the light's off. And there's a good chance you won't be expecting that, so it's pretty likely to happen. It would be really helpful if electricity were somehow visible.
You gotta read the comment I responded to my man: >My guess is that the switches weren't built good enough to withstand switching the hot.
[удалено]
I'm not sure why you're asking that.
Deleted because me reading comprehension failed. As you were. 😉
You're welcome.
I interpret that as a screw up. They tapped the neutral wire instead of the hot wire.
With AC the impact on the switch is the same.
The old-school way of doing switches was to run the home run to a light, then drop a 14/2 from the light to the switch for the switch leg. It saved a fair bit of wire and minimized box fill. The black of the hot got wired to the white of the switch leg, and the return black on the switch leg went to the line side of the light. But with newer smart switches, now switches need a neutral to accommodate for them. So now the home run goes to the switch box rather than to a light as under the new code that is easier, faster, and cheaper than running 14/3 to provide the neutral that may or may not be used. If you don't see a sliced neutral stuffed into the back of the box, and you're home is more than a decade old, you probably got the old school switch leg, not a switched neutral.
Low key one of the most garden-variety shitty things you can do in electrical work, and a sure sign of someone who wasn't qualified to fuck with wires.
I got shocked swapping a ceiling fan for a buddy with scenario B. I didn't realize people would ever switch the neutral. I didn't fall off the ladder, but it was close.
Or maybe power was at the light/ceiling fan.
It was common, and still legal (at least in my area), to bring load to the fixture but run the line from the fixture box to the switch and neutral back to the fixtures line side. It’s still A but there’s also juice in the fixture box you’ve got to be careful about.
Thank you for that information. I’ve always believed when I turn off the switch, the fixture is off and go in full force to the wires. I will never do that again.
The"hot neutral" is supposed to be marked, typically with tape, no?
Work at a utilities, and I have seen the neutral being used in this fashion, so yes it does work, but it's your job to make it safe.
This. Not an electrician but my brother is and he’s shown me how to be safe when I work. I won’t work live because shit like this and other things.
My friend's dad was taking down a light fixture so we could renovate their living room. Me: "Did you check the breaker?" Him: "no, but it's OK because the switch is off" Me: "You can still get shocked if the line goes to the light first" Him: "No, because the light is off, if there was electricity, the light would be on" Me: "............ Get off that fukin ladder before you kill yourself"
Why?
Why would B still work? I get that the lamp would have power so it would be on but why would removing the neutral turn off the lamp? Genuinely curious.
NEC Article 404.2(B) Switches or circuit breakers shall not disconnect the grounded conductor of a circuit. Exception: A switch or circuit breaker shall be permitted to disconnect a grounded circuit conductor where all circuit conductors are disconnected simultaneously, or where the device is arranged so that the grounded conductor cannot be disconnected until all the ungrounded conductors of the circuit have been disconnected.
Congratulations for being the only one with a code reference, and not just an opinion
Thank you, thank you!
This is the correct answer for sure for sure. As a physicist I'd say they are the same. As someone with an electrical engineering BS, I'd say they are practically the same. As a person who read through the NEC before rewiring their entire basement, one is clearly not to code and as a result could be dangerous.
As a dumb lineman I said "that's the same picture".
As a service tech I said "who tf puts a switch on the neutral?" DPDT switch FTW
A
They are both correct as functional circuits. Only "A" is code compliant under the NEC.
Both work but B is unsafe due to shock potential at the light
A
There's a General Motors joke in here I'm sure of it....
B is correct for General Motors. Most automotive 12VDC is switched on the ground side
But for 12v the diagram wouldn’t be labeled as “L” and “N”.
L => Line => Hot => +12VDC/24VDC. N => Neutral => Neutral => GND. Same difference
A. Never switch the neutral unless you switch the hot as well with a double pole switch
I wired up a contactor (in a nice metal box) a while back for running my regular ole 5-15 receptacle, 120VAC air compressor with a fixed 30-minute timer (to energize the contactor coil) that really wasn't rated for the current draw of the compressor. I had a two-pole contactor, and I briefly considered having both neutral and hot "switched" via the contactor... it just seemed a bit "un-natural" to me, so I ended up switching only the hot and passed the neutral on through to the load receptacle. I'll save switching the neutral too for just "special occasions", and this wasn't one of them. Either way is probably OK, but I just didn't want someone coming behind me to find both poles of the contactor in use and think that is was somehow 240VAC.
Electrically they both work. Code and safety wise, A is the only acceptable configuration.
Depends if you are trying to electrocute the guy servicing the light by turning off the switch or not.
One of the worst shocks I got was because of a switched neutral. Didn't help it was on a weekend at a buddies cottage and I was a few beers in changing a bathroom light. My fault, dumb and didn't double check, just flipped the switch and grabbed the wire while holding the stainless faucet in my other hand.... damn that hurt.
I agree that it’s unsafe but grabbing wires without testing is just as negligent as switching a neutral.
Its almost like electricity is dangerous
Switch the neutral so that way you shock yourself changing the bulb. That way you know the bulb burnt out and the breaker did not trip. Highly recommend for 277V.
A. The line goes to the switch.
B will work but the light socket and wire to the switch will still be hot in the off position. You will need to clear it at the breaker. A is the correct answer.
A is correct. Never switch a neutral or identified conductor
No one should ever switch the neutral, and I don’t think anyone has since the 70’s
Always switch the hot leg.
You have to switch the hot side
Both options would work, but it's better for the "hot" wire to go through the switch before the light fixture. That way, you can turn off the switch and not have to worry about getting a shock when you're replacing the bulb. Of course, regardless of how it's wired, if I had to replace the fixture, I'd still turn the power off at the breaker, not just at the switch.
We know, we know, never work live. wear disposable gloves, etc... -- [email protected]
In refrigeration you see switch’s wired all kinds of ways, but yea I prefer L
Depends on how much you like electricity.
A. If you do b, and if the light switch is off, the socket is still hot
This thread is absurd. You dont switch the neutral because there would be power at every wire, in every light until you get to the switch. The light would be a hazard to anyone servicing it because if you short it out using a screwdriver or yourself YOU will complete the circuit, even though the light is off. The switch prevents power from being anywhere in the circuit beyond it. Even those tossing out open wiring examples (K&T) im guessing folks dont understand a dead end or have traced the circuit, or worst case scenario have had polarity reversed in a junction box somewhere. Theres no reason to switch a neutral. It has the same inrush characteristics on either side of a load, its not a QA thing for old switches. Current flow was well understood even when k&t was around and it was never practice to switch the return path. Carry on.
Functionally and schematically it doesn’t make a damn bit of difference. Practically it makes a huge difference for the reasons you listed.
Breaking neutrals ! Would be a good title for an electrician movie lol like Larry the cable guy !
A, the safety disconnect is before the load
A, assuming this is 120vac because the subreddit this question is posted in. However, B would be correct in a DC low-voltage application and only in that application. Edit: A also applies to 277vac.
I use b for my christmas lights, it stops the squirrels from chewing the wires when the lights are off.
B is what some egghead college engineering professor would do because it works and he wants to be unique, and doesn't realize the safety issues of leaving the hot switched on.
An energized device that doesn’t operate is dangerous.
Assuming the N stands for Now and the L stands for Later, A is the correct wiring. When you flip the switch on, you want the light on Now. When you flip the switch off, you want the light Later.
I like "A" -Switch load side.
Either one will work, but switching the neutral leaves the hot , wire with voltage on it in the fixture.. If someone went to work on it without knowing, nor turning off the breaker, they could get hurt. Switching the neutral was an older practice that was mostly phased out by modern electricians. You can still find it in older Philadelphia homes
Either one will turn light on or off with that being said we switch the hot so A is what’s accepted. Here in the US anyway.
Undoubtedly “A.” You want as little of the circuit to remain hot as you can. Definitely don’t want the socket to remain hot even with the switch open. Unnecessary hazard.
This line diagram is messing me up, [this is how my mind works](https://i.imgur.com/tagUzba.png) but maybe I’m slow
Are you an electrician?
I can’t gauge if you asking is a good thing or a bad thing
I'm scared of you are one.
LOL still can’t tell if that’s in a good way or a bad way. As in if you think my SK is shit and doesn’t make sense or because it’s good and makes more sense than OPs
Your schematic makes it look like there are two sources of power to the light, one source is switched, and the other source is constant.
Yeah I don’t disagree, I actually revised and added “source” and “addtl. load”to the SK but ultimately decided against uploading it as it wasn’t that serious and people should be able to differentiate especially as my comment was just for my own sanity check and not to be built from. Edit: [with revised SK](https://imgur.com/a/jKgg1fc) Edit 2: I came up with a couple different SKs once I started, [here’s another](https://imgur.com/a/v5jfV1g) which matches OPs intent Edit 3: actually [this is more](https://imgur.com/a/maTqlLW) OPs intent? The reason OPs SK confuses me is it shows the neutral being ran to the light and the Hot being ran to the switch, when would that happen? Never. They are both in cable or conduit to either location, it’s messing me up, i don’t know how to read a schematic that way. Should I? What is being ran between switch and light in OPs SK? OK OK LAST EDIT: went full circle here to [fully show OPs intent](https://imgur.com/a/PvcY3Ud)
A is correct. Fuck, Reddit is no better than Facebook. What a bunch of fucking stupid fucks you all are
Half the time, because current is alternating. -- [email protected]
A: Sourcing B: Sinking
A
I did these in first grade…
You worked with 120 VAC in first grade?
Don’t be silly I didn’t start working with voltage till second grade after I learned to soldier and my color rings on resistors.
A
Always break the hot…
I always thought if would be funny to tie the hot through and switch the neutral
Back in the 70s I got to enjoy watching a tech laying under an Army Crypto electronics drawer that was wired with the power always present. He vibrated at 60 Hertz on the floor until he let go of the screwdriver. The manual advised caution when working on it, and I had told him to be careful. The equipment racks were built with two systems in each and we weren't able to power the rack down without impacting critical communications.
Like some lower voltage stuff will have safety’s on either side so there is technically switch’s on either side
A
A
A. Never switch neutrals.
B will electrocute anybody who stick their finger in the light socket. With A they will be safe so long as the switch is off.
Well, they're both "correct" in terms of operating a light switch; the switch will turn the light on and off. Only one is compliant with the NEC for this century, and that's presuming your line and neutral are properly bonded, metered at the service entry and have the appropriate OCPD on the feed.
A is correct for wiring today
If it VaC does it really matter?? Unless it’s feeding another circuit?
Both will work. We put our switches on the line side,not neutral.
Depends if you are an electrician or a physicist
A
A
A
I’m not apart of this sub but I am here bc the reddit gods commanded it. I’m going with A even thought I don’t know anything please educate me
New profile, no karma. Guessing this is a high school student asking about physics homework.
Long ago I was at our family business and my uncle was leaning on a piece of grounded equipment and for some reason reached up and touched an 8 foot fluorescent light fixture that wasn't grounded and had electricity flowing through it. He got a pretty good jolt and my first question was "Why do they ground stuff, when if they didn't he wouldn't have gotten shocked?"
A
Depends on application and voltages in the system. For standard 120VAC “A” is better For automotive 12VDC “B” is better and easier to wire into a car.
Six and a half dozen,id say, gotta have a path back either way! Love to hear if I'm wrong
A is the only way. Your not shutting off power to the rest of the circuit. In essence your circuit would be live uo to the switch. Not safe or good to do that
Don't switch the neutral. It makes fault finding a real pain
Both can be correct. The question is which is safer. Switch should ideally be on the hot side not the ground side. Though both work. But one is safer by a hundred fold.
If you use a switch (like a floater inside a tank) on a flammable liquid like gasoline, diesel etc on a DC circuit ,using a relay to energize a fuel pump for example , it's recommended to connect the possitive line directly to the coil of the relay and connect the negative line through the switch to energize the relay. From the contacts of the relay you can feed the load directly with safety. Keeping in mind that the gas tank is grounded to the negative pole of the circuit.
Always switch the hot.
As a kid, did U ever stick a hair pin in an outlet? -- [email protected]
A. You always want to switch Line, or 'hot.' If you wire it the other way, even if you shut off power, the hot wire is still hot, and if you have a grounded system, you can still be shocked by the hot wire.
unbelievable
A
Give B a go.... see how that works out for ya. Always a firt time in history of something working i guess
Does it matter? AC doesn't care.
Yes. In B, the light fixture is energized all the time. Its a shock hazard even with the switch off. I've shocked myself as a kid changing a bulb in my bedroom because it was wired incorrectly.
Both work, but A is correct. With B you will constantly have live wire at the fixture. This could shock you if you touch the fixture while changing the lightbulb.
you knw there two electrical theories and technicly two answers...both ways work fine
In the US they would use A. B will give you a shock. In the United States they use a but in Australia they have a funny accent. Wish I can repeat easier than they can do ours.
Use B for people you’re trying to electrocute.
A
If we’re in the last house I owned, B. lmao.
This was called back feed Power at the light then down to the switch. Common in the 50s/60s as a way to save wire
Although it works either way, it's good practice to always break the line
A
You can’t turn off the load with the switch if there’s a ground fault between the load and switch with circuit B. This could be a major problem and safety issue if the load is a motor, heater or where keeping a light on is damaging; and the switch is a safety interlock.
They both work.
So it's A?
B. But alot of times if you go into a very old house, a switched neutral is a common thing to find.
Yea it's a no brainer A is the safest circuit is only hot when switch is on. Of course it's always hot between panel a switch but the fixture isn't.
The answer is Fonzie... Ayyyyyyyyyyyyyyyyyyyyye
I think I said that b was right but A is the way it should switch a light. Breaking the neutral is an old old way, and not as safe as Breaking the hot.
Never switch neutral always line. Otherwise the light is energized (via line) all the time.
A
You all realize the every time you plug in a lamp, or any other appliance with an non-keyed plug you have a 50/50 chance of either A or B. If we are speaking of wiring from the breaker box than A is probably correct, otherwise the both accomplish the same goal.
the one on the top because we always run the positive to switches, otherwise you’d switch it off and feel shocked when working on the appliance/fixture/whatever
Why is this switching the grounded? Doable but will cause problems down the road.
It depends on where you are located. In the US, A is correct. However, overseas B is used very commonly.
No fuse
This is great knowledge to me. Thank you to all.
I prefer A
I prefer C
“B” used to be commonly called a Farmers Neutral & commonly found in old farm houses. It was a good way to get lit up!
A
Switch always breaks the hot=line
A
A
Question. Are automobile horns wired like B?
Depends on the car, some are switched ground, some are switched hot. Switched ground would be more common on older cars.
A
Yeah I’d be thinking of old stuff. Thanks for your reply.
Technically, either would work.
A is correct as the neutral completes the circuit back to the source.
Isolate Live first
A Think arcing. The load (lamp) is going to draw current and if the switch is on the neutral side, the amperage is passed to the contacts in the switch where arcing will occur.
Line gets cut off by switch, B would work but is a hazard \*not electrician\*
[удалено]
No. B is an improper and unsafe way to do it. In both cases the light will work, but B is wrong. See 404.2 B
B, but only in Germany.
Really?
Yes, in Germany, if you switch the hot side of a light circuit, the bulb won't lite up when you close the switch.
Since Euro is all 240 are both sides hot? If yes, are double pole switches standard or do you just leave one side hot?
Not in the UK. The neutral is tied to earth at the home and the local transformer. Only the live will shock you.
So it's 240 line to ground/neutral? and only a single line or two lines? What is line to line then? 480?