Non contact voltage tester false positive

Non contact voltage tester false positive. Nowadays, electricity is a basic need everywhere, you can not survive, and it is easy to say that you can even think about surviving without electricity in your home, office, at any place.

Electricity comes to our homes with the help of wiring, which is sometimes grounded and sometimes open.

It is very important to know that don’t touch the wires of power without gloves and to adopt safety measures.

If you try to fix a loose wire in a home without testing the voltage, then you can face an electric shock which is sometimes very dangerous to you.

Sometimes it happens to you that you are fixing a loose wire and you use a non-contact voltage tester, but still, it gives a false positive.

It is due to the static voltage or slight induced voltage.

Non contact voltage tester false positivenon contact voltage tester

It is necessary to have a non-contact voltage tester when you are working with power; it is essential for your safety.

It is essential to use these tester’s pens or voltage sensors because they confirm that there is no AC voltage, and you can touch it without bearing an electrical shock.

When you open an outlet of power or open the plug of an electrical appliance, always use a noncontact voltage tester because this device will help you to read the voltage in the wire.

It will also detect the current because if you know the presence of voltage in the outlet, then you can easily troubleshoot.

The following are some tips to stop this tester from giving a false positive.

Static voltage

At times, it happens to you that you are fixing a wire in a wall, and your voltage tester is not showing any sign of current. However, when you moved the tester at the top of the part now, it gave a positive single.

It is because of the remaining voltage which is still present in your wiring. It is called stated voltage, and usually, it happens due to the non-proper working of the grounding system.

Slight induced voltage

Sometimes the voltage tester gives a false positive reading; it is likely due to induced voltage. So don’t need to rely on just the results of a voltage tester. Always recheck the current with a multimeter device for the best results.

Stray voltages

If there are two pieces and they have electric field potential, but they do not have any current difference, then it is stray voltage.

If two objects are grounded, then there is always a chance of current between them due to their power.

Nevertheless, you will see in different electrical appliances that there is a huge current. This is one of those reasons why a noncontact voltage tester is a false positive.

Trickling between the insulation

If insulation is not done properly around the wiring in a wall, then the current or voltage will go through any kind of conductor easily.

That’s why it deceives the contact voltage tester sometimes and gives a false reading of positive results, and you cut the wire.

So don’t cut the wire just by testing it through one device. Always re-confirm it on a voltmeter and then cut your wire.

Ghost voltagesghost voltages

Ghost voltages are also a big reason behind the false positive reading by a voltage tester.

When it happens to you, then see those wires which are detached but still electrify alongside the wiring.

Return of neutral current from ground

In a three-phase structure, if the voltage is different, then some load will remain in a neutral conductor, and the earth will set an equal return way for it.

This will allow some current to constantly flow through the earth. It will make stray voltage and will give false positive reading to a tester.

Erosion or electrolysis

Occasionally, you face stray voltage due to erosion and electrolysis. So make sure that your wiring is safe from erosion and electrolysis.


If a non-contact voltage tester is false positive, then don’t cut the wires immediately because maybe it is wrong, and you will cut the wrong wire.

There are different reasons behind this troubleshooting, like static voltages, ghost voltages, and sometimes it is due to corrosion of wiring.

So always take proper safety measures and recheck the current in wiring from a multimeter.

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