How can you detect your neutral missing in 3 phase 4 wire system?

Answer 1

In typical residential wiring it is the white wire. If you look in the electrical panel behind the panel you'll see all white wire are "bussed" together and the black "hot" wires are attached to breakers. The bare "Ground" wires are also all bussed together. The White and bare wires are typically bonded together in the main electric panel.

If you have a volt meter and you wanted to check for neutral without taking off an outlet cover you could ground one lead and then touch the other lead to each side of a receptacle and if you get 120V that is the hot side and zero is the neutral.

Danger - if you are removing electric panel covers and exposing the internals of the electric box there is a danger of getting electrocuted.

Answer 2

If you mean check the voltage between the phase wire and the neutral you would use a volt meter or a volt ohm meter (VOM).

Answer

As the neutral conductor is connected to the earth (ground) at the supply panel, it is at, or very close to, earth potential. So, to identify the line (not 'phase', which is an incorrect term) conductor, connect a voltmeter (or multimeter, set to measure AC voltage) between line and earth , and it will register a potential of approximately 230 V (Europe) or 120 V (N America) with respect to earth. Always set your voltmeter to a voltage higher than the anticipated line-to-neutral voltage to prevent damaging the instrument).

Answer 3

Answer for USA, Canada and countries running a 60 Hz supply service.

If you have a regular digital voltage tester then run tests for voltage from hot to neutral (should be ~110VAC), hot to ground (should be ~110VAC), neutral to ground (should be ~0VAC), continuity between neutral and ground (should be low/no resistance with the breaker off for any continuity tests), continuity between hot and ground and hot and neutral (should be open circuit or very high resistance with the breaker off for continuity tests).

If this testing shows no continuity between the ground and neutral then the neutral connection in the receptacle may be open, the connection between the neutral wire and the neutral bus in the panel may be loose or a connection may be loose somewhere between the panel and this receptacle.

Also check the neutral on another circuit or two. If that is open too then the neutral bus may have come loose in the panel. Check that out and remove, clean and retighten the connections. If there is corrosion in the breaker box then you may need to disconnect, clean and reconnect all the connections (hot, neutral and ground) to avoid intermittent issues on other circuits as well.

If that doesn't fix it then there could also be a receptacle outlet, light switch, or a junction box between the panel and this receptacle and a loose neutral connection could be there.

Trace the circuit back to the breaker panel and check the neutral. If you find a point in the circuit where the neutral is connected then you can start working between there and the end of the line to find the open connection.

If you don't have a good neutral somewhere else along the circuit, but the neutral is connected to the bus in the panel then you will need to check and tighten the neutral connections. Make sure the circuit breaker is off when you do this. Check/tighten the connections to the neutral bus bar in the breaker box and work your way back out to the end of the line tightening the connections as you go.

NOTE: The GFCI must have a solid neutral and ground to function properly...if either of the 2 have a bad connection or break between the panel and box - it will not pass the trip/ reset test and will not reset at all.

If you have traced the wire run and tightened connections and found no other area on that circuit where the neutral is open and you still have no neutral at the subject receptacle then there may be break in the line just to that receptacle. You may be able to run a new cable from a known good receptacle to the one you are having troubles with and abandon the original cable going to it. Ideally you should try and make sure the original cable is removed or at least completely disconnected at each end and wire nuts put on the ends of the conductors. You might even want to tape a note to the wire to tell future electricians what happened.

If other receptacles also have open neutrals and tightening connections doesn't fix it the there is probably an intermediate break in the wiring anywhere between the breaker panel and the receptacle (something as simple as an overtight wire staple or connector can cause this problem - or a sheetrock screw has hit the wire in behind the wall nicked the neutral). Finding these can be a real bear (even with proper test equipment) because the break may not be complete so it comes and goes with the slightest little movement in the wiring. Even just a slight change in temperature can cause it.

If you run into that scenario then it may be best just to pull a new run of wire from the panel to the receptacle. That's the only sure way to eliminate the open for good (if it can not quickly be positively found and corrected) and save a lot of time (and headache) trying to isolate the problem.

As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.

Answer 4

hi'

just take a tester and put ina plug point at ur home ....

the bulb inside the tester will glow so it is phase

the bulb inside the tester willnot glow it is neutral yar that's it...........

Another Answer

You should be asking how to identify a 'line' and a neutral. A 'phase' is the connection between a line conductor and a neutral conductor.

This can be done using a neon tester, as per the original answer, or by using a voltmeter with one terminal connected to earth (ground). The line conductor will indicate a potential (e.g. 120 V in North America or 230 V in Europe), whereas the neutral will not.

Answer 5

This is a short circuit and breaker should trip or fuse should blow. If you put an ohm meter between hot and neutral with breaker off you will read very close to zero ohms. If there is a short circuit your meter is only reading the resistance of the wire between the measurement point and the short.

Answer 6

When using these types of testers always test the black to white wire and then black to ground wire. If the tester indicates there is a voltage to ground and not the white then the neutral white wire is open somewhere in the circuit.

Answer 7

using a multi-tester check the wire with has zero potential(voltage) with the ground