Electrical Troubleshooting

Electrical troubleshooting involves checking and resolving an electrical problem (such as when an electrical device stops working correctly). Common troubleshooting practices include checking if the power is on, the bulb has burnt out, or the breaker tripped.

2,086 Questions
Electrical Engineering
Electrical Troubleshooting

What are the different types of three phase motors?

synchronous and induction motors

Guinea Pigs
Electrical Troubleshooting
Santa Claus

What should you do to fix a light which goes out and comes back on by itself all day?

== == Tighten the bulb/plug Make sure both the hot (black) and neutral (white) connections under the wire nuts are solid, and that terminals (screws) are tight. == == <><><> If neither of the above tips help to fix the problem it could be caused by a loose connection anywhere else in the circuit. For example it could be a loose screw which should hold a wire tight in a terminal on a switch that controls the lamp. Always make sure you have switched off your electricity supply at the main breaker before you take a look at those cable screws!

If you don't know how to do that then you must call in a licensed electrical technician to fix the problem as soon as possible because a loose cable screw could be dangerous.

The reason for that warning is this: when the lamp is burning the loose connection is very likely to be getting hot and could start a fire. The danger exists even if the circuit breaker does not cut the current. (It may well not cut the current because it won't be higher than it should be...) Always be sure to switch off the breakers at the main panel

before you attempt to do any work on any mains power circuit. 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.




Home Electricity
Electrical Engineering
Electrical Troubleshooting

Can voltage drop trip a breaker?

A breaker is a current activated device.

New to these forums so, not sure on the etiquette of improving the answer above. I didn't see a button to provide a second answer. That being said;

While the breaker reacts to current and not Voltage, Voltage drop to a motor load will cause that motor to draw more current, which can trip the breaker. The higher current draw will also create more Voltage drop, etc. Your best bet is just to stay within the industry standard of 3% drop for feeders, 5% for branch circuits. If this question doesn't involve motors, then Voltage drop outside tolerance will eventually cause the device to malfunction, depending on the severity of the drop, but won't effect the circuit breaker.

Mobile Phones
Wireless Communication
Electrical Troubleshooting

What do you do if your cell phone screen has gone blue.?

i am 6 grade and long ago i dropped my phone in a cup of water. it did not work for a long time so i put it away for like months. well i wanted to use it again so i got it and put it in the frezzer for like 4 or 5 minutes chargerd it and now it works even better. put it in the frezzer if water damanged if worked for me.

Electrical Engineering
Home Electricity
Electrical Troubleshooting

How can you calculate busbar size?

Busbar Length x Busbar Size x 0.009

ex- Length= 12meter

Size = 60 X 10 mm

ie, 12 x 60 x 10 x 0.009

Ans = 65 kg

Can you please let us know what is "0.009" for???

Ans: 0.009 = copper density

Max. Current for 60 x 10mm = 60 x 10 x 1.55 = 930 AMP

What is "1.55" for??

Home Electricity
Modification of Old Electrical Work
Electrical Troubleshooting

Is a breaker broken or blown if it will not stay in the off position?

If a breaker will not stay in the off position it is defective, no matter how you wire it, and needs to be replaced.

there was probably a hot wire in that mess in that box and you just mistied them when you installed the switch are you sure that was a ground and not a hot going somewhere else

Electrical Troubleshooting
Industrial Electricity and Electronics

What is an electrical manometer?

Electrical manometer is an electronic manometer use to record pressures between two points. It is commonly used in recording pressure in bridges.

Electrical Engineering
Electrical Troubleshooting

What is meant by flashing a field in excitation?

A generator needs to have residual magnetism in its field coils to start the generation of electricity. A generator that has not been run in a long time will loose this magnetism. Because the field voltage is a DC supply, a battery across the field wiring will energize the coils instantaneously. Doing this several times will cause sparking when the contact to the battery is broken, hence the flash. This intermittent energizing and de-energizing will bring the residual magnetism back into the field coils. When the generator is started, the voltage output should rise to its normal level. If it does the magnetizing of the field coils to bring back the residual magnetism will have worked.

Electrical Engineering
Electrical Troubleshooting

Can you start 20kw motor on direct on line circuit?

No, the motor has to be connected to the line voltage through a set of fuses and then an electrical contactor. Also the motor must be thermally protected against overloads by using an overload block or heaters. This is to allow the motor contactor to drop out is a overload fault should occur.

Electrical Engineering
Electrical Troubleshooting

Why does an electromagnetic brake designed for a star connection not work in delta?

Probably the reason is in the different voltages between the star and delta connection voltages. An electromagnetic brake designed for the lower voltage of the star connection would burn out or open when introduced to the higher voltage of the delta connection.

Electronics Engineering
Electrical Troubleshooting

Why reset circuit needed in 8051?

You need a reset circuit in the 8051, as in every logic circuit, in order to ensure that it starts up in a known state.

Electrical Troubleshooting

How do you check the under voltage relay?

The way you check to see if an under voltage relay is wired properly is to disconnect the electrical supply. If the device that is connected to the load side of the relay does not start up or energize when the electrical supply is reconnected, then the relay is connected correctly.

Electrical Troubleshooting
Ford E-250 Van

Where can you find the fuse diagram for a 1997 Ford E250 Van?

Click on the link below

Click on Owner Guides

The owners manual ( which includes the fuse diagram ) can be viewed online

Air Conditioning and Coolant
Heating Ventilating and Air Conditioning
Home Electricity
Electrical Troubleshooting

Why would your lights flicker when your AC unit comes on and how can it be fixed?

Actually I have experienced this problem, as I bet have a lot of other people. An AC uses a large amount of electrical current. Whenever it switches on it causes a temporary power drain and lights will often dim or flicker. My neighbor is a retired electrician from Boeing Aircraft. He said it wasn't dangerous ,and the easiest and cheapest way to eliminate the problem was to limit the use of other electrical appliances. Like running the dishwasher late at night, when the tv(s) were off. Or the washer and dryer separately. Turn off all lights that weren't needed, etc. To prevent your lights from dimming you should have your AC unit on a separate circuit run directly from the main panel. The lights are flickering or dimming because the AC unit draws a lot of current when it starts up causing the voltage to drop on that circuit. Lights are sensitive to voltage fluctuations. Contact a HVAC professional and ask about installing a "hard start kit" on your AC compressor unit to prevent it from drawing the extra power from the house on startup. Some models already have built in supression circuitry and some don't. Yours probably doesn't.

Home Electricity
Electrical Wiring
Electrical Troubleshooting

How do you test a 30 amp circuit breaker?

If the breaker is in the distribution panel and you have a volt meter check the circuit for 120 volts to the neutral or ground. If there is 120 volts present on the terminal the breaker is operational. Turn the breaker off, if the voltage disappears the breaker is operational.

It is not recommended to do a load test on a breaker of this amperage due to the high wattage load needed to trip the breaker.

Electrical Wiring
Electrical Troubleshooting
Industrial Electricity and Electronics

What does an electric current continually seek a pathway to?

An electrical current continually seeks a pathway to ground.

Electrical Wiring
Electrical Troubleshooting
Industrial Electricity and Electronics

The pathway taken by an electric current is called what?

Its circuit. But this is hard to marry with lightning, which is the path of an electric current.

Consumer Electronics
Electrical Troubleshooting

How do you hook up two 12 volt batteries to get 12 volts?

Connect them in parallel, negative post to negative post, positive post to positive post. This configuration will give you the same voltage and twice the crank capacity if it is being used on a vehicle. Great setup for cold winter starts.

Electrical Troubleshooting

Why does my laptop freeze on YouTube?

Maybe because you have too many items or something , maybe , just maybe , SEAN BEAN hacked into your laptop and freezed it with his freeze / cold ray gun that he uses in lord of the rings !!

Job Interviews
Electrical Troubleshooting
Industrial Electricity and Electronics

Interview questions for electrical maintenance?

1. Describe the electrical systems you have worked on and how did you get your training?

2. What is your experience with electrical schematics?

3. What is your experience with ladder logic?

4. Describe the malfunctions you have experienced with PLC hardware?

5. Describe a tough electrical troubleshooting problem you have experienced, and briefly explain the steps you used to solve the problem.

6. What is the difference between a digital signal and an analog signal?

7. How often do you use a personal computer in a typical day? What do you do with it?

8. Describe a process problem you have experienced and how did you solve it?

9. Give an example of a tough loop you had to tune. What were the problems? And how did you solve them?

10. What brands of VFD's are you familiar with.

11. Describe some of the malfunctions associated with VFD's, and give an example of a tough VFD problem you had to solve.

12a. Using Ladder logic, write a program that will START and STOP a motor with momentary START and STOP push buttons. (Provide a sheet of paper)

12b. Add ladder logic that will turn the motor OFF after running for two minutes.

13. Describe the steps you take to troubleshoot a 3 phase, 480 volt motor that continually trips the heaters.

14a. Why is the earth pin in a 3-pin plug the longest and the thickest?

14b. Explain the purpose of grounding.

15. Describe a control panel you wired, designed, or modified. What was the purpose of the panel and state each component you used.

16. Describe the difference between a sourcing input and a sinking input.

17. Why do you want this job?

PWR 1)sensitivity of ELCB

PWR 2)about MCB ratings

PWR 3)earth resistance and earth compounds

PWR 4)what is LDR

PWR 5)your electrical activity in your society


PWR 6)transformer and related formulas

PWR 7)industrial lightings

PWR 8)what is the nature of electrons

PWR 9)use of ballast in tube light


Electrical Troubleshooting

What meter is used to bench test a motor for a short or an open winding?

An Ohmmeter or the ohms function on a typical multimeter would be used to bench test a motor for a short or an open winding. First, be absolutely certain that the motor under test is disconnected from any mains. Using a low ohms scale, x1 or x10, one would expect to see some resistance across the motor. The resistance can be quite low depending on the size of the motor, but should not be zero. If it is a motor that has brushes and a commutator, rotate the shaft, with the meter connected, through a full revolution. This rotation could help identify a single defective winding in the rotor. To check the stator, remove one of the brushes so that the measurement current only passes through those windings. Of course, it would help if you have a known good motor of the same kind so that you can compare the readings.

Electrical Troubleshooting
Industrial Electricity and Electronics
50 Hertz Industrial Electricity

What are the methods to calculate and improve power factor?

The best way to improve power factor is by adding capacitors. Low power factor is due to reactive loads (motors, pumps, etc.) that are connected to your electrical system.


The best way to improve power factor in the case of motors is to use a motor drive, like a Variable Frequency Drive. These drives allow very precise control over a motor, unlike the very sudden, jerky starting and stopping across the line seen when using a motor starter. They eliminate the huge inrush current required to start motors that causes low PF.


1) Power factor can be calculated by connecting an energy meter [P] (voltage coil in parallel & current coil in series with the load), a voltmeter [V] across load and an ammeter [A] in series with the load. Measure P, V & I.

Since, Active Power (P) = V.I.Cosϕ

power factor = Cosϕ = P/VI

2) Power factor is usually (industrially) improved by connecting a shunt (parallel) capacitor bank at feeding end.

How it works??

Inductive loads contain both inductors and resistors. But due to phasor difference of coils and caps when voltage is applied across both, the two currents results in a smaller net current finally. So now the angle (ϕ) between the voltage phasor and current phasor is lessened. When ϕ is reduced, Cosϕ is risen resulting in a higher power factor.

Jeep Cherokee Laredo
Home Electricity
Electrical Troubleshooting
Light Bulbs and Artificial Lighting

Why would the electricity shut off when you plug a light bulb in a certain outlet?

The problem sounds like it could be a simple as a loose wire at the outlet, sometimes the outlets are wired using the stab in terminals in the back of the outlet instead of the binding screw,any movement causes the circuit to open. However if you are tripping the circuit breaker when you plug in your device a short is the reason.

Home Electricity
Electrical Wiring
Electrical Troubleshooting

Why is electric breaker to dyer keeps getting hot and tripping breaker.?

If the circuit breaker to a dryer, or to any load, keeps getting hot and trips the breaker, then either the load is pulling too much current or there is a loose connection in the breaker or breaker panel. Either condition must be fixed to reduce the risk of fire.

Electrical Troubleshooting
50 Hertz Residential Electricity
50 Hertz Industrial Electricity

We have a problem with induced voltage. We measure 220 VAC in the L and 45 to 60 VAC in the N. There is no chance of changing the cable. How to avoid this?

Normally the neutral wire of every circuit is connected to the neutral bus bar in the main breaker panel. Because the neutral bus bar is always connected to ground you should never be able to measure any voltage between the neutral wire and ground.

So, if you are measuring 45 to 60 VAC between the neutral and the ground it could be that the neutral wire has become disconnected at the breaker panel or somewhere in between the panel and the point where you are measuring that voltage.

Assuming the load equipment - an appliance, a motor or whatever - is still connected to the hot and neutral wires, then, if there is no connection to the neutral going back to the power station, in effect you are measuring the line voltage from the hot feed as reduced by the resistance and/or reactive impedance (total reactance) of the load. That could be making 45 to 60 VAC, as read by your meter, appear on the neutral wire coming back from the load.

A simple way to prove if that is the case is to unplug or disconnect all loads - appliances, light fixtures, motors, etc. - from the circuit in question. If you cannot then measure any voltage between the neutral wire and ground the next thing to check is the resistance between the neutral and ground.

First of all switch off the circuit by switching off the breaker at the main panel - or remove the circuit's fuse if it has a fuse and no breaker - and then use the resistance range on a multimeter to measure the resistance between the neutral wire and ground. If it is a very low resistance then an open neutral is not the cause of your problem. If it measures as a very high resistance or an open circuit then your problem is an open neutral.

The reason for the open neutral must be found and that fault must then be corrected urgently.

In the Discussion page to this question please let us know what you found when you did the tests suggested above, and whether or not this advice helped you to locate and fix this problem.

To be able to help you better it is important to know exactly here this circuit is located geographically in the world and to have confirmation whether - as inferred from your question - it is a 50Hz system with one 230V live and one neutral or whether it is actually a 60 Hz system having two 120V hots (+120V and -120V) balanced around neutral.

Then, if necessary we shall have to consider what other reasons could cause the fault you have described but to be able to do so it would help to know exactly what you found when you did the tests described above.


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.





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