The Dangers of Shared Neutrals: How To Avoid Being Shocked

I wish you would have taken a moment to warn the newer guys about shared neutrals well all right bruh here's your video [Music] Garrett Robinson on my shocked on the neutral video had an actually really good comment he said awesome presentation as usual but I wish you would have taken a moment to warn the newer guys about shared neutrals even if the circuit you're working on is off it doesn't mean that the same neutral wire isn't being used for a separate circuit elsewhere that is still active this is common practice in my area especially in the older buildings let's do a drawing all right now so we're going to talk about two things we're going to talk about this whole issue but I also want to talk about another kind of crazy phenomenon where you might be able to test between two whites and get 240 volts depending on the situation first off I just need to like restate this for people that haven't watched the other videos that I've made current is always traveling out on the black back on the white right it's a complete Loop but in a 240 volt situation current on the larger circuit is always going like this so that means coming back on the red and going out on the white you also have current this is why current doesn't travel in a white most of the time it carries an imbalance when the loads are not even so we're just assuming these are both completely perfectly even loads that are plugged into these things two vacuum cleaners or whatever we're not going to have any current flow on that neutral we're going to have an outer circuit so for to understand how what neutral current is sometimes we have current on the neutral a lot of times we don't if there's a completely balanced circuit most times we do though because nothing is truly that perfectly balanced so what happens though instead of having like um if we ran two 12 twos out to two different loads we'd have like one neutral that went to this white and we'd have one neutral that went to the red we'd have two pieces of 12 too so we're not sharing a neutral at all if we disconnect this neutral like we know everything's dead if we disconnect this hot we know this neutral is dead because it's all going back like independently but if we have a shared neutral situation say we have a 12 3 a lot of older homes like 70s era 80s era they would run 12 threes from their panel outside and run them everywhere just to save one conductor you know what I mean like you could you saving that one conductor was cheaper than doubling up the amount of 12-2 that you're running through a house so a lot of GFI circuits in kitchens and things like that that are kind of close to each other they would just make joints in the back of a junction box put one circuit worth of plugs on one and then you would just pass the other circuit through onto something else so we have a shared neutral we have a black and a white that go out and they share the same exact neutral and at a certain point they split them out into two different things so what happens is if we um if we were to like say say I've got in my panel I've got a 20 amp breaker here and I've got a 20 amp breaker here we don't ever have breakers on neutrals so we flip the handle of this breaker and we assume this circuit is dead so we go and we touch this neutral and we're like oh yeah I can touch the neutral I can touch the black everything's safe right but we don't realize is that right here this circuit is still a complete circuit so you still have potential all the way through this whole circuit so this part of this neutral can still have current on it this part won't absolutely because we don't have a complete circuit anywhere and the current always travels in a path of a loop so current is not going to travel in a place if it's got a loop here it'll travel in that Loop but it's not just going to like magically go out here and sit here on a wire that's not connected if there was another completed Loop like absolutely it would but it doesn't have a complete Loop that way so there's not going to be any current right there there's only current in this portion of the circuit but Mr helper going in not realizing being like Oh I just shut the black circuit off and didn't realize it's a shared neutral circuit and none of the journeyman had actually told him like Hey dude there's potential for that neutral to be able to bite you depending on where you're actually taking it apart and messing with it you could still have current flowing on this one and still get shocked by a neutral so be really really careful on shared neutral circuits oh by the way make sure you guys join our Discord we have Discord servers just go dead on the App Store and download Discord I know it's another app you gotta download but seriously you have thousands of electricians in our Discord server all day every day just talk and sharing videos stuff out in the field asking code questions like helping each other out it's a really cool Community definitely go join our Discord Link in the description below also go check out electricianu.com we have continuing education we have a membership there's courses there's classes there's all kinds of stuff that's free for all the Nerds like us so check out electricianu.com all right so now let's talk about the other weird situation where you could get shocked between two neutrals so say that we have like a big uh blue junction box and an attic somewhere and we've got these two attic lights and for some reason somebody ran two circuits and they shared a neutral so they brought everything into a central uh junction box and then they went out to two different lights and one of them is on the red circuit one was on the black circuit I probably a weird improbable thing but I've seen weirder and let's say instead of receptacles on the uh those things it's lights so we actually have a completed circuit through here whereas a receptacle is not completed until you plug something into it so what would happen if we just went in here and we like disconnected the neutrals I left everything else going the breakers were on we just decided to reach our hands in there open up neutrals first and just disconnect all neutrals well we just basically mixed out this wire right so like now this whole wire is not a thing anymore it's it's still got potential between here and here and it's still got potential here and here so you could get shocked between these two new neutrals if you're if you have like both of these neutrals sitting out hang at the box and you're just being Mr Mr awesome over here and you touch between those two neutrals you're gonna get shocked you're gonna get 120 volts going right through you because now you are completing the circuit there's a complete path through that whole thing so you got to be careful about that that's why you always turn everything off when you're working on it same thing over here right you got a wire here and a wire here hanging out of the box well if you become the thing that completes the circuit you're gonna get shocked between those two neutrals but it's still going to be 120 volts well what happens when you do it without the main neutral you're like thinking oh I'm so smart I'm just gonna cap off this wire I'm gonna put a nice little wire nut on that thing because that one goes back to the panel I'm not going to get shocked you still have these two wires and what happens now is now you have a 240 volt shock on your hand because basically instead of these wires be in white gotta stop thinking about the color wires color doesn't really matter electricity doesn't care about the color wires now you have a complete red wire that goes all the way through and you have a complete black wire that goes all the way through foreign because again you were a dummy and you didn't turn the breaker off when you started working on this you're just taking joints apart well now you have two white wires that when you touch between them you're gonna get 240 volts so you can get shocked twice the amount of pressure um as was on there before so there's a few dangers on working with shared neutral systems and you just have to be really careful this whole shared neutral thing there's a reason why there's breaker ties there's a reason why from a manufacturer we have two pole 20s where it's like two Breakers two single poles slapped together and they have one handle tie and in code we're actually supposed to put our two circuits in and have a common trip or either a handle type or there's like a mechanical tie that you put around two single pole Breakers and make sure if one trips they both trip or you have to have a two-pole breaker where that thing's already integral and both of them shut off you can't have one of these circuits that's able to be shut off off while leaving the other one on while leaving potential still between two different things if you're going to work on one part of this you need to make sure that both of those circuits are shut off so there's no longer any way for there to be potential between the combination of these two circuits now leave some comments below if there's any other like weird situations that I didn't talk about or things that you can think of I'll absolutely do some videos if they're worth Merit all right Mr Garrett I hope I did use some justice that was actually a really good comment like thank you for leaving that uh give me something to talk about so if you guys are wondering what video he's talking about click here check this out this is a video and you get shocked in a neutral if you also want to just like know what a neutral is or what it does click here really good video love you crazy people see in the next one

Channel: Electrician U

Views: 217,589

Keywords: electrician, electrical, electricity, dustin stelzer, electrician vlog, construction, commercial, residential, electrical vlog, electrical courses, electrician courses, electrical class, electrician class, electrician school, shared neutrals, shocked on neutral, dangers of shared neutrals, avoid being shocked, shared neutral circuit, shared neutral circuit breaker, 12/3 romex uses, old building electrical, customers questions, journeyman tips, neutral drop, current affairs today

Id: GJu3UF5k5uU

Length: 8min 45sec (525 seconds)

Published: Mon Nov 28 2022