Understanding an Open or Loaded Neutral 

Two comments that might help people: First, the key idea is voltage drop. Imagine a simple circuit that doesn't even have a switch. You attach hot and neutral to a simple lamp base with a bulb in it. This isn't realistic, but it helps get the idea across. The voltage on the hot terminal will be 120V. Current flows through the resistance provided by the bulb and this resistance causes the voltage to drop across the bulb. In fact, it drops 120V and the voltage on the neutral terminal will be zero. A voltage drop occurs ONLY when current flows. If you disconnect the neutral from the lamp base, current stops flowing. Therefore, the voltage drop across the bulb becomes zero. The terminal from which you disconnected the neutral is now up at 120V. No current is flowing, but the terminal is at 120V, ready to bite you. This is what happened in the circuit in the video. If you open a neutral in a circuit with current, you stop the current. All the voltage drops upstream of where you opened the neutral become zero and the voltage of the neutral on the conductor coming from upstream will go to 120/240 and the other neutral (heading back to the box) will be at zero. Here's the second comment: Never trust a neutral. Here's what I mean. I had to replace a pigtail in a lighting outlet. Before making changes, I checked for voltage, hot and neutral, found voltage, and then opened breaker. I saw the voltage go away, so I knew that I had the right breaker (since I saw things turn off). "Never trust a neutral," means that, even though I had taken all due care in identifying the proper breaker, when I untwisted the neutral splice to do my work, I did not assume I was safe. Good thing, because, as the neutral splice opened, it arced. How was this possible, since power was off, as proven by probing for voltage and killing the circuit? Simple. Someone screwed up. Somehow, they managed to tie the neutrals of two circuits together somewhere. So, voltage went off on the hot in the outlet when I opened the breaker, and there was no voltage on the neutral, but there *was* current in the neutral from some other circuit (who knows where) and, when I opened that splice, I interrupted that other circuit, the voltage drops went away, and the neutral in the splice came up to 120V. Never trust a neutral. Hope this helped.

I'm not a certified electrician, but have been keeping myself educated. I first started when I was ten years old in 1964 by reading books at the library. I started fixing table lamps and other electrical things for neighbors and friends. I later got into electronics and started fixing home record players, audio amplifiers, and other things as well. This did work well for me overall as in 2006, I got a job at a company that built power control equipment for subways and light/heavy commuter and other electric powered trains. I was also able to point out design faults in the equipment we built, mostly when wires were too close to what are called load measuring resistor packs that would get very hot. They were wired in parallel to track circuit breakers and were activated in short bursts when a circuit breaker tripped to measure current flow to determine if the short still existed. Sometimes my advice wasn't taken and equipment would fail when put into operation. I also studied building codes before I rewired the bathroom and kitchen in my house built in 1913. There's still some antique light switches and old wiring using single wires and ceramic knob tubes in the house, but there's no heavy loads on those circuits. I've subscribed to your channel and hit the bell. There's always something I can learn from videos like these. Thank you.

I understood what he said because I already saw a video where somebody actually explained it in an easy to understand manner. Terry gets a C- for his teaching skills on this one.

Well, you explained it, but sped by the part about the splices. Might want to show that. Thanks.

As a home inspector I appreciate your calm demeanor and ability to communicate that things can be corrected.

A picture is worth 1,000 words. You showed us everything except the cause of the problem. When it came time for that, all we got was a verbal explanation. Clear as mud.

Between me watching another electrical video before yours, then specifically looking for one about open neutrals (finding yours), I finally understand what's happening. I believe I've seen that open neutral light, on a simple 3-prong plug tester, at my parents' house on certain outlets as well as at switches. Not being an electrician, obviously, I'm sure it'll be fun trying to trace the direction the current flows from each plug/switch to the next. 😕 I do appreciate your video though and you making it easy to understand. Idk why but I'm very mechanically inclined but have always avoided electricity issues beyond installing lights, switches, and outlets. I created a mental block for myself. LOL Thanks again!

I was having trouble with a TP Link smart dimmer switch. A Google search led me to this video, which was extremely helpful. It was great to see how to test the switch and eliminate problems. It turned out that I had the line and load wires reversed, hey both were black. Thanks for helping me out in a jam!

I’ve run into this quite often in my house that was built in 1930 with cloth wrapped wires and porcelain insulators.. started replacing wires and outlets and figured out it was easier just to cut out all the old and start at the breaker box instead of routing them back the same way originally done and avoided a lot of unnecessary splicing.

Thank you Terry for adding to my knowledge, I'm trying to install and automatic electrical switch for a backup generator. I'm not and electrician but I am an engineer and know just about enough to get myself killed. lol I'm trying to learn enough to survive this project. Thanks again. and just incase someone is wondering, the answer is NO I will not be doing a video explaining how to do this once I figure it out. It's too dangerous to share with the general public and as an engineer it would be irresponsible of me to share this information with unqualified persons. I am actually unqualified myself so I definitely will not be sharing it with anyone else, Sorry.

Showing the upstream splice would be nice. Showing how to correct the problem. Thanks for your videos.

being a good teacher is explaining complete details no matter how small or trivial it may seem

I’ll never forget my first open neutral!

Perfect explanation. Just went through this exact same thing. Followed my neutral wires and found where somebody had spliced them and they had come apart. Thank you.

While working for a heating company years ago I got a late night call for no heat. I get there to see a fairly new warm air furnace and instinctively I reach for the power switch mounted on the side to see if it's on and to see if may have been installed up side down. (on being in the down position) On touching the switch box I was lit up like a Xmas tree because the whole cabinet was hot! Turn off the breaker and open the box to see lots of wires under one wire nut.... and the connection was burnt to a crisp. There was NO neutral and nobody had bothered to tie the ground to the box or cabinet. 15 minutes later I had trimmed back to good wire, added a second wire nut, and grouped the neutrals into bunches of 3 with a jumper, plus tied the ground to the box. Back in business. In hind sight, had they run conduit to the switch box there probably would have been a secondary neutral path via ground, but this was a Romex run from the ceiling to the unit WITHOUT a hard ground connection. In that case it may not have provided heat but I wouldn't have been blown to the floor with a hot cabinet. Did I mention this house had a dirt floor? All the better reason to have a good neutral and ground. I never did find out who wired this thing but now I always check with my inductive tester first.

Very much appreciated. The average DIY'er often has very important things to understand about electricity, and certainly needs to take every precaution. Mistakes are often things that were never even thought of as possible, or careless oversights and assumptions.

“So the answer is you have spliced up stream” What the hell does that mean? You explained everything well except the answer to our problem. I don’t remember splicing anything.

This is the best answer I find. The demo is superb. Thank you for the efforts!

Hi and thank you for the information ! In our country - Bulgaria. The really old houses wirings, probably in the oldest lefted on villages houses has only two fuses for breaker for the whole house from the transformer to the everything around the house - one for the live wire and another one for the neutral, because couple of time ago in our country, the law requires only dual house wirings /with only live and neutral in the house, without ground/ and also - contacts with no grounding /the appliances manufactured then in our country was at law - double insulated/. So, one time i started diagnosing him, telling father to stop the fuse, and he misappealy take off the neutral one. So I wondered for a little why it has live on the both conducters even in the destributions on the wall /in the housing them in our area, it has destribution boxes in the walls before to go to every Individual outlet or socket. And there, the wires for the sockets and lamps are tied up together. I am figured it out suddenly, so that my dad has taked off only the one fuse - neutral one from my grandpa's house. Haha But here how it can happen dangerous faults !!!

love your diagrams.. you explain things very well... thank you for sharing,,,

Great explanation. I've done electrical work for years but it never hurts to brush up on my skills.

The more I study electricity the more I realize how much I don't know 😅

Great video Terry, I know what you mean, I have seen this type of work in Mexico, Brazil, and the Philippines. It can get dangerous, but they do what they can and get by. Best of luck with your new course - looks good!

Thanks, this explains the theory behind half of my problem. My current issue is: Mobile Home with panel wired like a subpanel (bonding at the pole) Panel has 50 amp main breaker with 4 conductor pigtail to 4 prong plug Plug to outlet on pole protected by another 50 amp breaker/shutoff. Direct to meter/ power co. Power off at pole for all work😀 turned on for test only After scratching my head for the longest time, I disconnected all circuits (8) Capped off all hot and neutral wires, left all grounds connected. Tested main lugs Test showed 120 between ground and neutral just like your example but...... I also see that if I connect a test load (60 watt bulb) to any breaker if I switch the Load on I get 0 volts on the red terminal and 240 on the black When the load is off it is 120/120 Took the cover off the supply on the pole the neutral was burnt and open Explaining the 120 on neutral to ground. What causes the 120/120 shift to 0/240...? Thanks for the help

Well it was good verbal explanation but not good visual in a circuit diagram. Schematic in electricity is were the rubber meets the road... This video needs more work with a point A to point B fault and remedy. Missing is what is upstream causing the fault. WIKI would say this article needs to be more comprehensive.

Add a junction box between the panel and the switch. Then disconnect the nuteral wires in the juntion box to demonstrate the open circuit.

Correct me if I am wrong... the neutral being hot is a result of backfeed from a common load passing back to an unbonded open circuit in the neutral... it’s also possible to blow up electronic appliances from a phase because of a non bonded neutral causing a 240v feed between loads. I learned on outdoor 120v branch circuits to use a double pole safety cut out switch disconnecting both hot and neutral as the neutral can have a different potential to grounds in the field which is a safety hazard even on circuits where the hot is switched off at the breaker. This is especially important when the circuit is brought to a location like a light pole or older commercial settings where ground potentials can vary widely.

Helpful info, thanks. I have come across this situation recently. And this is the explanation I have been looking for!

My left ear learned something today.

Hello, Terry. My class and I watched your video and we had a question about circuits. We are currently studying single circuits and parallel circuits and we would like to know if there is no load, will the current still flow through the connectors (wires)?

If it helps to explain, that exposed splice on the white (neutral) he was showing in the switch box would have been open (un-done). So he wouldn't be testing a "neutral" any longer. Only a section of white wire between the light and the switch. Unscrew the light bulb and you wouldn't get ANY reading between the switch and the end of the white wire since the light bulb filament is acting like a "coupling" (connecting the black to the white at the lamp) and extending the black wire that brings power to the lamp. Yes, a diagram or more physical demo would help.

Just had a similar situation. Outstanding explanation to an annoying issue. thank you!

If he would of shown and explained it with an electrical diagram what is happening at lot of more people would underestand.

Have to agree. I had hot neutral and this video has left me even more confused as to why. Need to explain exactly what you mean by open neutral. Is it open that the panel or 'upstream'?

House wiring can be tricky to analyze from limited check points. But if you can keep in mind the overall circuit and source of the two points where you are reading a voltage and think about where it could be coming from (like through a load) you can figure most out.

Great video I did same mistake couple month back.. thank you

Why not show what happened in the box up stream? Also, with a plug in tester, it will show where the open neutral is, won't it?

You didn't show the main part!!

hii Terry, thanks for your good info video. i learned something i have one question to ask you, pls. i found a live wire in a switch of ceiling fan, and switch lead to the ceiling fan. i also found a i thought to be neutral wire connected spliced to another wire, in fact it is a load returned neutral.. so my question is, when you see wire in a switches box, how to tell a neutral wire is neutral or load returned neutral ? thanks andrew

Hi Terry, My main power comes from my meter to an outside cutoff switch just a few feet away, then travels about 120 yards to my house. My main 200 amp panel in my house has the neutrals and the grounds on the same bar. Doesn't my main panel in the house essentially become a sub panel since the outdoor switch is in place? So should I separate my neutrals and grounds? And do I need to add a ground wire between my outdoor panel and my indoor panel? thanks

all current ultimately goes back to neutral and or ground rod through ground water back to power generation location. At substations there is a huge array of copper rods into ground to actual generator and or transformers. We installer alot of sub stations. Many do not realize all current has to go in circle back to lowest potential. Shalom

"He found that he had open splices further up the circuit". Well... that's fine & dandy. But... That really doesn't give you the actual reason why he had 120 on his neutral. People are gonna ask about those open splices further up the circuit, where the cause of the problem is. So what actually was the cause? For example, the same neutral, at the opposite end of the circuit might probably be connected to a hot leg. If that were the case, then you've given a reason why your neutral is loaded. If someone's sewer is blocked & wants to know why... the EASY answer is: there's a problem somewhere down the line. Well, no shit. The answer is with the actual problem, which everyone wants to know. Unless... I've missed something? Sorry. Don't mean to jump on your back. Thanks for taking the time to enlighten the uninitiated.

Thank you for sharing your knowledge. Much appreciated.

Thanks for explaining so clearly.glad to find ur channel

You need to show a diagram. The switch must be on, right? if the switch is turned off then no power should be at the neutral.

I wish I could see a diagram of what happened..

Very informative. Didn’t know that!!!

my.. you explain things well Terry... Thank you so much..

Terry, Thanks for your videos. But,...As a retired industrial/residential electrician, "I" understand the situation. But people who really have no business messing with electrical wiring have no idea what you are talking about without you showing by example what caused it, rather than to just mention it. Without being rude, without that, the video is rather useless for the unknowing novice. Sorry, just constructive criticism. BTW, the worst messes I have ever had to correct is when people of such, mess around with 3 way, 4+ way switching. Totally screwed up. Novice people have no idea what NEC Code is either. These people also need to realize that they can screw themselves beyond belief from their insurance companies when regardless of being the home owner or not, as some jurisdictions still say that's ok. But MANY City charters say NO and have absolutely in no uncertain terms that it is not allowed. That you MUST use a certified electrician who will sign off and some as in the State of Tenn., requires a City Inspector to approve, before use. Some cities, such as Chattanooga, and others have city codes that are far more detailed and additions beyond the NEC. And of course you have to comply.

My only question after watching this video is what is an open or loaded neutral?

Thank you, Peter.

Watching the video second time and now I understand 120v not coming the light on, I had that situation where a guy kept saying it’s the light fixture itself or I was not using right the wire nuts a hard head person but this video gave me a good understanding to keep moving and don’t stay to long dealing with the light fixture that is not coming on even if you have 120v

Do what I say not what I do. That's what I say to my apprentices. 😂

In USA the plastic boxes don't have a ground strap on the screw threads, they should, like Canada, eh?

I know this is old, but you are the only source I found to explain this problem! I was searching for a day and a half trying to figure this out.

Terry, I've never spoken to anyone that had a great short cut for testing a tripped breaker. For example, there is a circuit that had 8 recepticles switched out. Breaker get turned back on and instant trip. I've never been able to locate the culprit other than going to each one and taking them out to inspect (provided the answer isn't obvious through visual inspection). Any thoughts other than checking every single outlet? Of course, the assumption is each wire was simply put back in original positions.

For the confused....checkout the diagram on his website. He explained it perfectly in the video but the diagram allows you to trace the path and makes it easier to envision. You can see where the path is broken so current doesn’t flow, but voltage still gets to the neutral. Touch the neutral and you complete the circuit.

i feel sorry for you Terry!... people it was an open Neutral!!.... he doesn't have to show you anything!! just imagine in your head the WHITE WIRES NOT CONNECTED!!.. that's all.. plain and simple.. if there not connected the circuit is open which means its not complete which means with AC you have to have a complete circuit or you will have no light! once he hooke the white wires back up the circuit was complete again.

Well explained and to the point, no stupid side jokes or useless back stories

Great video. Based on what you explained and some of the public comments, folks, if you are not an electrician, don't play with electricity. Mistakes will ruin your day... At best... I'm 11kV qualified so I do have clue...

Wish there was a drawing

Nice video but you didn't show the problem!

In the normal situation with the switch on, if ground to switch shows 120, and neutral to ground shows 0, does that suggest that the voltage drops after passing through the bulb filament? If so, why do you still measure 120 (in the second mid-wired part of the video) after current passes through the filament (I.e measuring from neutral to ground). Should’t there still be a voltage drop (if its passing through the filament)? Also if alternating current alternates why doesn’t the neutral become hot for the fraction of time that the polarization changes? Sorry if these are silly questions..I’m new to this Thanks

Great video, thanks for the explanation.

No solution. Down vote

Terrible video - He never showed why the problem or how he corrected it.

I also would have like to see what he did in the box! I like your videos because the sound and video filming are great with no camera shaking.

Thank you I get it. I had electric shop in HS and was in electronics in Air Force however in my late 70s. Alternatively I could use same wire size as to the present outlet to the heater hookup. The original line is long so there might be some line drop.

Do you have a video explaining fault isolation of problems in GROUND connection that would cause this symptom ?

Thank you. I have outside lights on a store that show a hot line wire but no current when timer is switched on for the neutral. I’ll have to follow the circuit up stream and see if a splice has been disconnected. Definitely 👍🏻 and a sub.

Ha! "Current" topics. Nice! Great video, thank you.

Excellent video... Thank You!

Thanks for sharing. I've got continuity between all 3 of my hot, neutral, & ground; whats up w/ that?!... thanks

Awesome video! Like a ground side switch on dc! The only light going off is the one over my head haha.

do you know anything about low voltage house wiring, I have a friend with low voltage switches with relays that controls the 120 volt side. She has a breaker on the 120 V side that can not be set. I think there is a short or an over load no the 120 side of the breaker. What do you think?

Enjoyed the lesson

I was hoping this video might answer a question about a situation I was having about a voltage drop in a Hot-to-Ground check. I show an open ground on a single receptacle leading to a gfi plug. When I checked the wires, I get good voltage from Hot-to-Neutral, but am showing about a 45 volt drop from Hot-to-Ground. The run is a grey romex under a deck and some parts are buried. It a critter gnawed at the line and got through the insulation, but that cause a partial drop between Hot-and-Ground (showing about 80 VAC on a 120 VAC circuit)?

I tripped my trip switch this makes sense why a little bit more, i tried using a neutral from a socket as neutral is missing in light switch area in uk and now I don't know how to fit tings in light socket that require neutral any ideas?

Great Example sir thank you

Hi Terry I have a single pole switch with one black cable and one red cable. Its the one that turns on the light on a triple switch. Are the colors correct?

do we get same thing if we disconnect phase in single phase system? neutral on phase wire up untill point of disconnection? if load is connected of course?

Grounded or floating neutral. Ha a journeyman electrician (supposedly) almost got me killed by floating a neutral feed into an outer building from the main MCC. Good explanation.

I got a new deep freezer. unplugged old appliance, plugged new one up, everything in circuit stopped working. tester indicates open ground...Never had an issue before.. what's your advice as to where to begin finding my problem? thanks in advance!

would upstream mean the break in the neutral is somewhere between the first light and the service panel? or between the first light and the last light of the circuit? If the neutral was disconnected at the second light how would that cause backfeed at the switch? the circuit would still be closed from the first light back to the panel and the backfeed would actually be at the neutral wire between the second and third light would it not? please help me understand

Those open neutrals can be tricky...and deadly... I was called to a newly constructed home on a service call because the plumbers said they were getting shocked by their faucets... It took me a while but I finally tracked down and fixed the problem: The neutral on the load side in the meter base was never tightened at all...

Hi, I was replacing a receptacle today & when I started to replace it, I realized they used both a white wire for ground & neutral. How can I find which is ground & which is neutral?

I had a call that a 5 door refrigerated case was out. In this case were 5- 115v 9watt fan motors. I thought, why would all 5 motors go at one time. Took out my meter and yep, 208 volt going to the motors. Now this circuit was in place for sometime, and there was a renovation going on at this time. So I know this does happen

Hi Terry,... Thanks for the video. I'm confused if your friend changed the wiring upstream correctly or incorrectly... Would like to see.how his work caused the condition... I had the same exact experience with on outside doorway light, but I did not change any existing wiring.

You should provide a diagram in conjunction with demo, it would add clarification for those who may not get it from the demo.

Hello sir I want know one thing .for a example main power 420v three phase a/c.imagine red phase is taking 50amp Yello phase 60 and blue 25.tell me sir what is correct four cable I want to choose.

well done however how do you know if you’ve lost your neutral if everything in the building is operating on 240 V

Great explanation

Hello. I have a unused 220 line coming to an outlet for a range. Can the outlet plug be remove and splice in another line same gauge and extend this line to another area to hook up baseboard heat? In so in essence using the existing box as a junction box?

Question - is it allowed to run a visible white wire in a kitchen cabinet at all? For example a transformer for LED below the kitchen sink? Danger from possible leaks and mechanical damages?

Excellent information,tanks 👍👍👍👍

Got a strange one here, had an issue with getting shocked of the meter box, the power co. opened the meter box, told me that the meter box was outdated and at fault because the neutral was not bonded to the box there. They made me install two new ground rods along with the existing plumbing ground inside. While disconnecting the power up top, to replace the meter box, with both hot wires disconnected from the pole, but the neutral still crimped, I went to check continuity to ground at the meter box and blew the fuse in the meter. I then checked voltage, and found I have 117v between the neutral wire from the pole and the meter box itself? Both hot leads from the pole are disconnected, the main is off, yet I got 117v seemingly from the neutral lead from the triplex run from the pole?

Excellent video thank you! ⚡️

How do I get half voltage on a circuit? Or partial voltage?? Thx!!

Question could you check for an open neutral by turning all lights on and then checking for ground to neutral voltage anywhere seeing that there bonded at the panel or would this be a direct short?

So if i have same problem on a cealing fan ... The ground n neutral. Just connect them to the hot neutral ? At first i connected the ceiling fan the correct way and did not turn on .. Or my othe fixture lights. ???