Questions tagged [neutral]

a circuit conductor that normally carries current, and is connected to ground (earth) at the main electrical panel.

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What is the purpose of the 1 Mega-ohm 1/2 watt resistor between neutral and ground, in a vintage audio amplifier (SONY model STR-7800SD)

I own an old SONY radio / amplifier, model STR-7800SD. I opened it and I saw a resistor between one of the AC lines and the chassis. The funny thing is that it has a REVERSIBLE 2-prong plug! So, I ...
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Formula for calculating the current in the neutral of an unbalanced 3 phase system

Morning All, my first post here! I am looking at 3 phase calculations and how to find the current in the neutral for an unbalanced 3 phase system. I am aware that it can be drawn out to find the ...
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Difference between phase and polarity?

Long story short, I did a bit of a career change, I'm now doing electrical engineering with an architecture firm instead of embedded systems. So I've jumped from the simple world of DC to the land of ...
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1 answer
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Do devices not tolerating swapping live and neutral exist?

Multiple types of domestic power sockets around the world (including the ones in my country) do not distinguish between live and neutral even when ground is present. I am shopping for an AC-DC PSU ...
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Why use vector sum for calculating neutral current?

In a three phase system, we use a vector sum to calculate resulting neutral current. I don't understand why we use vector sum. The resulting neutral current is actually the sum of instantaneous values ...
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10 answers
3k views

Why is the fuse connected to the live wire?

As far as I can understand the concept of AC, it does not matter which wire is live or neutral as this changes like 100 times per second (implying 50Hz) I believe. I read the fuse must be connected to ...
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Is it correct to connect the grounds of high-power and low-power switched-mode DC supplies?

I want to control some WS2811 lights with a Raspberry Pi. The lights need 24V ~180W ~8A from a supply such as this, whereas the Pi wants 5V and presumably low power from a supply such as USB. I ...
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LED Wall neutral current problems

I’m running a film project that involve a huge Led wall. I have 1000 screens that can pull .6 amp each they are balanced for load on a 400amp 3 phase supply but I’m measuring the same current in the ...
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Using mains in a project with just a power cable (ground wire)

I'm going to power a 235 V band heater with a computer power cable (has fuse, SSR and thermocouple, too.) Everything is enclosed within a box, and there are no open junctions etc. I am unsure what to ...
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2 votes
2 answers
4k views

Current measurement in LTSpice

In LTSpice, measuring a current through passive elements (components) is very straightforward. Now I'd like to measure a current through a neutral wire where no element is connected to it. So can ...
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SVPWM: space vector generation star point shifting - effects?

I keep seeing that the space vector generation (as a part of a FOC) is generated around DC Link / 2. What effects would be expected if the (in this case isolated) star point were permanently shifted? ...
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burying the neutral to used less cable for welding a long way from the power source

Of course we are not talking about code or best practice, but hypothetically if someone wanted to do some welding a few hundred meter from the closed power point could he/she run one hot conductor to ...
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Energy meter neutral current measurement

I was reviewing an energy meter specification and I came across neutral current measurement. What is the importance of neutral current measurement in an energy meter for three phase power supply? I ...
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1 answer
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How does a single phase shared neutral circuit actually work, physically?

Okay so this is a two part question. First Question is probably more of an ELI5 question. But I am a fairly experienced electrician (NOT AN ENGINEER mind you.) but I have a generally good working ...
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1 answer
210 views

What to use for neutral protection [closed]

I need information on "the protection of distribution system through effective grounding techniques." I want to know the possible protection schemes for neutral as fault current or return ...
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How to check if Neutral is grounded properly?

I was thinking of buying a Residual current device but I don't know if the power supply to my home is grounded properly or not. For initial testing I used my multimeter to check the voltage coming to ...
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How does leaving the neutral line not connected to device lead to burn it? [closed]

When an air conditioner (inverter AC) connected to the source 220V/50 Hz the circuit breaker became off and each time I tried to make CB on it returned to off directly. After the maintenance center ...
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Is high earth to neutral voltage in single phase power supply system indication of high earth resistance?

In a single phase power supply system, if I measure the earth to neutral voltage, can I use it to indicate the health or status of the earth resistance i.e. if E-N voltage is high, is it due to earth ...
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How to connect live and neutral and earth connection in AC devices plugged into socket?

I know that when I have a fixed lamp in my house I have to use a single switch on the live wire. But when the device is connected using a plug the live wire and the neutral wire vary depending on how ...
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Would a person receive a shock/risk death if they completed two ends of a neutral wire?

I know this seems like a silly question but I'm trying to make sure I understand the neutral wire. So I know if someone touched a neutral wire (assuming everything is wired 100% correctly) carrying ...
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1 answer
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How a high Earth to Neutral voltage affects electronic equipment like L2 or L3 switches? [closed]

We have lot of communication equipment installed recently in our organisation. From then, lot of pressure on us to reduce Earth to Neutral voltage at the input of our communication equipment like L2 ...
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3 votes
2 answers
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Why do we connect neutral and ground at the transformer? [closed]

Why do we connect neutral to ground at the transformer, why can't we just connect that neutral to the ground at our house?
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3 answers
2k views

What's the use of neutral wire in single phase home supply? [duplicate]

I am aware that the neurtal wire provides a return path for the current to the power source. But that neutral wire too, is connected to the ground at somewhere between the load and the source. My ...
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Switch type for electrical generator bonded to floating neutral

I have an electrical power generator and for it to properly work with it connected to the house it must be converted from bonded neutral to floating neutral according to these instructions. I was ...
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Connect the oscilloscope to equipment with a common neutral and ground

I watched a video. At 3 minutes, the situation is shown when neutral and ground are joining. Why can this be dangerous? If we are talking about an oscilloscope, the crocodile must already be connected ...
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Running long underground line without neutral or safety ground using transformer, is it to code?

My prior question asked about a single wire earth return [SWER] system. Both questions are aimed at meeting the same end requirement but this is a sufficiently different method that many of the issues ...
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What are the reasons behind marking neutral and line terminals on a power supply AC input?

Even though AC has no polarity, almost all the power supply AC inputs or most AC powered device input terminals indicate line and neutral terminals as L and N just like in the following example: Is ...
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Wiring 3P+N Device to 3P+N+E Connection

I have a 415V compressor with a 3-phase Commando plug in the configuration 3P+E, however my wall socket is 3P+N+E. Is it possible to change the plug on the compressor to a 3P+N+E without connecting ...
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1 answer
174 views

Running a long 120VAC line without a neutral

Source is a home 120/240VAC with pole transformer. I want to direct bury a 500 foot 120V line to run some battery chargers and dont need more than 10 amps. Why cant I only run a single large ...
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Role of the neutral conductor in three phase systems

In a symmetrical and balanced three phase system no current flows on the neutral conductor. Obviously the real electric power distribution systems are not perfectly balanced, so there is a current on ...
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3 votes
3 answers
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What does it mean when my car inverter's labeling says "Neutral Floating"? Is it safe to use?

I recently came across a fairly old car inverter. It plugs into a 12v DC lighter socket, and outputs 115 Vac at 60 Hz, and has a normal American outlet on the side of it (with a ground pin, which ...
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L and N switched, from a functional point of view, what difference does it make for the device being powered?

Consider a generic single phase AC 240 V (or 125V) device for home use such as a hair dryer. From a purely functional point of view, what difference does it make if a phase is switched with the ...
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1 vote
1 answer
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Designing PCB with AC Live and Neutral on two layers

I'm designing a smart socket that will route 240V AC Live and Neutral to a voltage regulator and also to a relay that will control the current flow. Due to the limited space, it will be easier to ...
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6 votes
5 answers
9k views

How can a circuit not have a neutral?

I've been making plans to install a NEMA 6-50 outlet in my garage, but I don't understand how it can not have a neutral, and instead have two hots (at 120v each) and a ground. What completes the ...
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Normally Closed Negative Output, Positive Input Relay

I'm attempting to wire up my remote start in my manual transmission vehicle to ONLY start when the vehicle is in neutral. The way that the transmission works is like this: When in neutral, resistance ...
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1 vote
2 answers
499 views

Can I put a low current relay between line (or neutral) and the ground wires to detect polarity?

Can I put a low current (<5 mA) 230V coil, NC (normal close contact) relay between one wire of mains and the ground (earth) wire in order to check mains polarity? In theory if the wire is line (...
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1 vote
3 answers
1k views

Line to ground faults

I am having a trouble understanding the concept of line to ground faults,and ground in general. In this simple single phase circuit, does current reach the load and the circuit operates normally? ...
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5 votes
4 answers
9k views

Does the neutral wire have any voltage?

In this article, the author talks about 3 phase and the magic of a missing neutral wire. And there's the following paragraph: In a 3-phase system the voltage between any two phases is 3 times ...
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Neutral wiring in residential homes

I understand from the diagram below that the neutral wire provides a return path to complete the circuit so that the current can flow. But once the current goes back to the distribution transformer, ...
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1 answer
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Why no current in neutral wire_kids question

One school child asked me - If current means flow of electrons, or entering to a bulb from one wire (Live) then going back through another wire, then why there is no current in the neutral wire, ...
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2 votes
1 answer
1k views

Why short circuit occur when the hot line touches the neutral wire (aka ground)?

The charges move from negative (hot wire) to positive/negative (neutral) to make the device work right? So why would the Short occur only when they are directly connected? Wouldn't they just flow ...
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Circuit for Neutral point of 3-Phase mains

I wonder if the 'Neutral Point' as mentioned in the attached image is correctly labeled or not? Is there any mistake in this 3-phase circuit design? Edit 1: Also it looks like the 'Neutral point' is ...
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Odd voltage readings between phase-ground, phase-neutral, neutral-ground

Recently i tried gathering voltages from few AC outlets in my house. I got following readings using a dmm Phase-Ground = 398V-400V (should be around 240V) Phase-Neutral = 230 V Neutral-Ground= 210 V ...
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1 vote
1 answer
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Question on Ground/Neutral connection for a 220V equipment

I sketched the following schematic from a motor controller board that has to be operated at 220V from L1 to L2. The earth wire is connected to the chassis of the machine. Where I live, it's common to ...
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1 answer
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Home electrical transmission question [closed]

AC current is sine wave with 60 hz frequency - how is this helpful in understanding electricity and transmission? Does the sine wave progress through electric wire or stands static and oscillates? ...
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1 vote
1 answer
129 views

Why is earth at 0 V with respect to phase?

In 3 phase transmission lines we have different voltages depending on how we measure it. Phase to phase voltage is going to be 1.73 times more than phase to neutral. So far I understand everything ...
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7 votes
4 answers
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Why cut both live and neutral wires?

It is a common practice, for high power loads such as boilers, furnaces, etc., to install a circuit breaker that "cuts" both live and neutral wires - at least in Europe. In my search for EVSE, I saw ...
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Can connecting just neutral wire of power supply to a PCB (VDD not connected) cause sparks and burn out decoupling capacitor?

I have an embedded system and one of the PCBs in the module should be connected to a 5V power supply -> positive(+) and neutral(-). The NEUTRAL knob is directly tied to the GROUND knob in the power ...
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10 votes
6 answers
8k views

Am I compensated by the electricity company for electricity that exits my home on the neutral wire? [closed]

DISCLAIMER: I am not an electrician or electrical engineer. Let's say that all I have running in my home is a 10 watt LED light bulb (nothing else). This bulb uses very little of the electricity ...
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1 vote
2 answers
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Meggering Three Phase Motor (Phase-GND, Phase-Neutral, GND-Neutral)

When meggering a three phase motor, could someone please help me understand the values we would expect to see for a motor with no insulation or ground faults. From my understanding: Phase-GND: ...
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