What Causes A Switch To Spark? (Causes+Fix)

Sometimes, when you switch on or off the switches, you will notice some sparks. Such things are quite concerning and stressful, especially if you are unaware of the reasons behind the sparks. But why do the switches spark? 

In general, switches spark due to the load arc that occurs when the electricity attempts to jump from one point to another. Some common causes include worn-out switches, too much load, and hanging switches. To fix the problems, change the old switches and ease the load on the same.

Switches sparking while turning on or off is the last thing you want. It can be very dangerous if the problem persists. Read this article till the end to find out the reasons behind switch sparking and how to fix the problems.

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What causes a switch to spark, and how to fix it?

There could be a lot of reasons behind a switch to spark, but identifying the real one is quite difficult. 

However, here are a few reasons behind a switch spark I encountered.

If you have such a problem, you can try checking these points.

Load spark

A load spark in the switch happens when the flow of the electrical current doesn’t stop in the switches. 

When you switch off the switch of any particular appliance, like a light or fan, the current jumps from one contact to another after separation.

There is less voltage for the current to continue because the contacts separate after switching off.

The current gets extinguished, which causes a little spark.

Worn-out switches

If the switch contacts have worn out and become very old, the switch will have a little spark whenever you turn it on for any appliance. 

The switches wear and tear and become very old due to excessive use. 

It is also natural because every product will become old one day.

Excessive load

If one switch operates multiple fixtures, it causes an overload in the switches.

Due to excessive loading of the current flow, a switch may spark very often. 

For example, if you have the switch rated for 10 amps, but the circuit is rated for 15 amps, it creates an overload over the switches.

It will cause a spark in the switches. 

A light switch is rated for 10 amps, which is common in most houses. 

The problem in switching occurs in commercial buildings with too many fluorescent light fixtures.

Also read:

Hanging switches

When you put the switch in on or off position, you should do it firmly and quickly, and not slowly or hang them in between. 

Hanging creates a problem in the connection, and the internal contacts remain far away from reaching the appliance you are switching on. 

It creates an arc for which you see a spark from the switch.

The voltage at peak value

In some switches, like the fan, the supply to the fan is AC voltage with 170V.

To calculate the same, you can multiply the actual voltage by 1.414. So, in this case, it is 120X1.414= 170 V(rounded off)

While turning on or off the switch, if the timing is near the peak value and the gap between the voltage points matches the spark voltage gap, the current will jump through the switch gap and cause a spark. 

It is normal.

Switch arc

A switch arc occurs when the wires are close to each other for jumping but not connected. 

In that case, the arc generates excessive heat and causes some sparks. 

If the spark is little, there might not be any problem.

But if the sparks and arcing increase, there will probably be a fire hazard.

How do you fix a sparking switch?

When a switch sparks too often, you should immediately fix the problem to avoid serious problems. 

To fix a sparking switch, here are some steps:

  • If the problem is load spark, you can worry less about it. 
  • If the switches spark because they have become old and worn out, you should replace them. Old switches cannot carry enough as they used to in the beginning. 
  • If the problem is overloading, ensuring that the circuits and the switches can handle enough amperes. Do not use a light with fewer amps and a circuit with more amps. 
  • Stop hanging the switches if the switch sparks. Constant hanging causes sparks.  
  • Sometimes, you switch on or off a switch when the voltage is at its peak. Sparking at such times is normal. The current jumps and causes a spark. 
  • If the problem is a switch arc, make sure that you correct the situation soon. Connect the wires properly, bend, and put them back. 

What are the other signs of a defective wall switch?

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Switches can become defective in many ways. 

When a switch behaves abnormally, like sparkling or making noises, it means there have been some problems.

When this happens, it is time to replace the switch. 

Here are some common reasons behind defective switches:

Temperamental light fixture

Sometimes while turning on a switch, for example, a light, it takes time to switch on or flickers for a moment. 

It is not supposed to happen unless there is an issue with the switch. 

If the appliance takes time to switch on, there is a problem with the metal parts inside the switch. 

Maybe the metal parts have worn out, for which the contacts fail to connect and complete the electrical path of the light.

Noisy switch

Faulty switches will make several noises, like buzzing, sizzling, popping, etc. 

Sometimes, the sounds are the result of loose connections.

Ensure the wires inside the circuit are tight and in good condition. 

These sounds are generally signs of worn-out or defective switches.

Over time, the switch will start sparkling lights.

Warm switches

A dimmer switch will use more heat when you operate the switch.

You will feel it, especially when you turn the switch off. 

The dimmer switch works by evaporating some heat from the full current flow to dim the material, like the lights of a light fixture. 

If the dimmer is hot, there might be some problems.

Maybe it is deteriorating and needs a quick replacement. 

However, general toggle switches should remain cool. 

The electricity is not flowing if you feel the heat even in these switches. 

Over time, the switch will keep failing more and start sparkling at some point. 

Another reason is overloading.

A switch that can handle 15 amps installed in a 20 amps circuit is more likely to heat up. 

The rule is to replace the switch and install a switch having the amps same as the circuit.

A warm switch can also occur due to loose wire connections.

Loose or stiff switches

Fingers can understand the condition of the switches much more than anything.

They are the best detectors.

If you find that the switches are loose or tighter than usual, the switch’s mechanism must have worn out for a long time. 

A worn-out switch is dangerous and should be replaced before any serious issue occurs.

Can you fix a sparkling switch?

It is considered normal if the switch creates a tiny spark when switching it off.

You do not have anything to worry anything here. 

It is due to the electricity jumping between the contacts. 

However, you may replace the switch if you are concerned about the sparkling. 

If the sparks are caused due to serious issues like arcing, you cannot repair the switch.

You have to replace it with a new one. 

It is better to replace a switch instead of fixing it repeatedly.

Besides, it doesn’t cost much, and a good quality switch lives longer. 

Can a faulty switch cause a fire?

Generally, an arc switch is very dangerous and can cause serious fire hazards.

Arcing happens when the wires do not touch but are close to each other for a current jump. 

An arc generates excessive heat, therefore, resulting in a fire hazard at some point in time. 

Sometimes, sparks happen during little arcs when the light is flicked off. The current takes off the last jump.

Arcing can occur due to various reasons.

Some of them are:

  • Sometimes the arcing will happen when the contacts wear out inside the switch. Due to this, they do not connect well. If you flick the switch slowly instead of firmly, the contacts hover close and create an arc. 
  • Loose wires can also cause arcing and fire hazards. It causes constant arcing that further causes fire hazards. Switch off the power circuit and tighten the wires to prevent arcing. 

What causes a spark in the outlets?

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When it comes to outlet sparking, you should know the different types of sparks and the reason behind them:

  • You should call an electrician to investigate the problem if the spark is white or yellow. 
  • If you get a burning smell after a spark, that is abnormal. Call an expert immediately to fix the issue. Later on, this can cause fire hazards. 
  • Again, if the spark is big and seen out of the outlet, you need an electrician to fix the problem. 
  • Call an expert soon if the spark lasts longer than a second and continues to burst. 
  • If the spark is blue, remains for a second, and doesn’t have any smell, it is a normal spark. 

Here are some reasons behind outlets sparking:

  • A short circuit is a common and dangerous electrical accident among all. A hotwire touching the ground or neutral wire creates a short circuit and makes the outlet spark. Excessive current starts flowing, for which the outlet gets overheated, starts sparking, and may also cause fire hazards. Avoid joining wires and overloading.
  • If your outlets ever come in contact with water, they will cause sparks when you switch on the circuit. It is very dangerous, and you must fix the issue soon. Otherwise, there will be a serious short circuit. Avoid contact with water.
  • Your outlet will surely spark when you overload a circuit by plugging in too many appliances. Plug in limited applianced.
  • Over time, the outlets can become old, worn-out, loose, and damaged. It further makes the outlets overheat and spark. Change such outlets soon.
  • If you install the outlets improperly, there can be sparks and, sometimes, fire hazards. You must call a professional if this happens.

How do you prevent sparking switches and outlets?

  • Prefer doing the installations by professionals. They will do all the wire connections better, and you won’t have any problems. 
  • Do not let any water enter the outlet or switch. While working, make sure the surroundings and your hands are completely dry. 
  • Do not use only one appliance in one outlet. Use limited appliances for one outlet. 
  • Ensure the circuit amp can handle the power of the appliance you have plugged in. The amp of the switch, circuit, and outlets should be able to handle each other without being overloaded.
  • Repair and replace the wires, outlets, and switches when they become old and wear out. 

If the sparks are blue that remains only for a second, there is no risk.

But, if the sparks are bigger, white, or yellow and remain for more than a second, you should immediately call for a professional to investigate and fix the issue.

Final thoughts

The switches can spark for several reasons, like worn-out switches, loose connections, excessive loading, hanging switches, arcing, and switching on or off during voltage at peak.

Replace the switches from time to time before you become worn-out and old. Check for loose connections and loads. 

Always keep the switch in on or off position firmly and do not hang them in between. 

Sometimes, arcing can cause both sparks and fire hazards. Little sparking due to a slight arc is not a very big issue. But if the arcing and sparking are too much, you should take immediate steps to prevent fire hazards. 

If you find any faults in your switches, like loose connections, arcing, loose or stiff switches, noisy switches, etc., fix the switch soon by calling a professional.

Reference: Light switch spark encyclopedia

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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