BROKEN NEUTRAL – HOW TO FIND IT – HOW TO TEST THE CIRCUIT AND THE VOLTAGE READINGS TO BE EXPECTED

What happens when we have a break in the neutral conductor?

This LearnElectrics video came about because of several posts on social media about testing electrical circuits that have a fault. In this video we will look at a situation that I had, a while back, in a domestic property with a radial socket circuit and how a broken neutral affected the test meter readings.

There are always many questions on broken neutrals, what effect will they have on the circuit, for instance or how can we spot a broken neutral and why are there different voltages around the circuit.

Moving on to a lighting circuit, I once had a message that when the lights are turned on, they don’t come on, but when the customer tried to fix it himself, he got a shock off the neutral – why?
And many more.

We will start off with a standard radial socket circuit with 5 outlets, and we will keep the explanations and reasons very simple, so that everybody understands.

In this video we will show you how the voltage readings can be affected, what makes the voltages change, and what these test voltages are telling us; the clues they are leaving us so that we can find the fault more easily.

And always remember to work safely, especially if carrying out live testing.

This is video number 205 and to view all our videos type in LearnElectrics all one word into the YouTube search bar.

Visit our YouTube channel where we have many more videos on a wide range of electrical topics.

[whitefields]

This is what YouTube is for. Short concise explanations with excellent graphics, free at point of use. Thanks for making the effort to publish.

[richardlewis]

I have tried explaining this to our apprentices and get a confused look back. I will be showing them this from now on, thank you

[no_short_circuit]

Thanks again for taking the time to explain things in ways that I can understand.

[Paulrogbucksbeach]

Yes it’s an interesting one. I’ve had a poor mains neutral and the lights were still working as the earth ground was the return. Pretty dangerous situation. Sometimes can be hard to spot. Great video very informative

[curentarul]

Great video!
Maybe in the future, you will make a video about the broken neutral in three-phase circuits, where the effects are more serious.
Thanks!

[brianhewitt]

Fault finding is always interesting, thanks dave

[paulellam]

Good stuff as always, helps to understand behavior of the circuits in fault conditions. many thanks!

[TitchgamerRG]

Great video as always Dave.
Come across this a few times myself!
The last time was on a electric Hob though!

[freezefoot]

Thank you for this. Much appreciated as always.

[mAkills]

Here in 3 phase 4 wire supply (India) this fault is known as floating neutral. In domestic service this is disastrous as the voltage will float anywhere from 0 to 415 between phase and neutral point due to imbalance and spoil the connected appliances.

[markyd]

Had this fault on a lighting circuit last at the neutral in a jb . take for granted that a neutral will be safe to hurts

[funnyshortsdaily]

I have a hot to ground that has 120v and 17v to neutral. Similar receptacle has the opposite.. is this a neutral open?

[kjellg]

Here is a puzzle: in Norway, distributon pre 1995, 3 phase 230V IT distribution. No Neutal only line conductors. 230V between them. Every Christmas eve at about 17:00 some lamps in our home would shift to moonlight. Being about 10 years old I got my first lecture into 3 phase theory and later became an engineer in electronics/telco.

[matt]

Usually fault like this you will assume is reversed polarity or dead short. You made this crystal clear in a few minutes video...

Best teacher ever!

[kennyla]

Break in the neutral or lost neutral. Tester picks up induced voltage between L-N because of the floating neutral. When a load is turned on the L is connected to the broken N through the load and when both are at the same potential the meter will read 0

[ja_adam_]

Basic question for you but I was wondering, am I right in saying that current returns down the neutral not volts. I thought voltage was needed to push current round a circuit so how does it return without this ? Also how can there be current returning if it is been used in the appliance? Also where does this current go? Does it disappear at the transformer, can it not be reused?

Please answer thanks for your videos

[mundent]

Looking at the tables, at no point is there 240 between L&N whether the lamp is in or not. I have a fault on the kitchen sockets where there’s no power to the appliances but there is 240 between L&N. I was getting 240 between N&E then I disconnected the dishwasher and the fault cleared, so I thought. It showed 0v between N&E, 240v between L&N so I plugged in the kettle and nothing. Tester shows L/N reverse but even so, I should still get power but nothing

[synthwave]

I have a similar problem and the electrician could not find the fault. When my light in the lounge is off, the bulb still glows. Measuring the 2 pins in the light socket shows 36 Volts A.C. while the switch is off. Surely this cannot be induced voltage ? So where does 36 V AC come from in a 240 V circuit then ?

[ammarbasrah]

Professor, in short, when examining the buffer, we separate the pregnancy and the swivels off
When examining continuity, we also separate the load

[abcddef]

Im confused in my situation, all lights and sockets work. However one of the light (led) flickers when turned off. Checking the switch both neutral and life wire are hot.