What exactly is the difference between a surge protector and a fuse? Can a fuse protect the electronic devices from lightning instead of surge protector?
Last Updated: 27.06.2025 12:41

Lightning arrestor is a spark-gap device, and can be installed anywhere. What is important, is that the wire is thick enough to withstand the lightning bolt and conduct the energy away from the building.
But it can get overloaded, and no longer works.
OK, this is Mohan Rajaratnam’s definition of a Surge suppressor.
Which is the worst Bollywood movie you have ever seen and why?
2024–10–11 [Bobby Sanchez Bobby Sanchez ].
[image of Common-mode choke]
Here is a simplified AC power diagram.
Is the question then , "why buy a surge supressor, if the fuse alone protects the electronic circuits from a lightning bolt?".
The bolt then partially travels down the line to your home.
If the nominal power is 4,000 watts then the current at 230volts is 16 amps.
Do you think Andrew Tate and Nigel Farage are part of a "similar phenomenon"?
P = e* I, so since I is 16 amps, then the voltage dropped is 1/16 volt or 0.0650 volts.
so, the loop of wire then, when put together with another loop reduces the ‘noise’ on a power line.
2024–09–27 [ Mohan Rajaratnam Mohan Rajaratnam ] . Thinks you can get free electricity from nothing : Mohan Rajaratnam's answer to Is it possible to generate free electricity at home using a magnet or other low-cost methods? If so, how does it work?
He said he loves me, but why is it difficult for him to leave his wife?
Once the voltage goes over 0.0650 volts, then this fact can be used to amplify the difference, and turn the circuit breaker off , furthur down the line. Essentially that is what a RCD/GFCI does, it compares the incoming current, to the outgoing current, and if the difference between the two currents is over 5mA, then it trips the circuit breaker.
eight
It’s been three xxx five werks, and there has been no response to my follow on query on his Commment to my answer.
What are the differences between promotions and sales?
2024–10–14 [Omar Gharbi Omar Gharbi ]
What is lightning?
but this device (an Inductor) … impedes the rapid changes in the current.
Why does Russia support Palestine in the Middle East conflict?
At least they know the answer if they wanted it.
The third is lightning and “how it gets conducted into a home.”
For this case there are devices called Metal oxide varistors (MOV).
Have you ever had a scary dream about a loved one or friend soon after their death?
2024–10–10[John johnson John Johnson ]
This is 'the assistant's answer'
The other is “what does a “fuse” do?”
Dementia risk begins in childhood, not old age, scientists warn - PsyPost
This is a photo where a lightning bolt took out a home's complete mains distribution box, and a lot of electronic gear as well.
Mohan forgets that a fuse is a one-time device, and needs to be replaced if it is tripped.
nine
2024–10–16 [ OO OLAOYE OYEBODE ]
“ A surge suppressor is the one which is connected at the input supply so that when there is a sudden change voltage it bypasses thereby protecting the (circuit) and electronic components”
This is an electronic circuit designed to clamp voltages so that the Voltage Potential that appears at the outlet is never going to exceed the nominal value.
New Study Finds 1 Promising Way To Keep Colon Cancer From Returning - HuffPost
Fuses, on their own, then operate much slower than the MOV variable resistance, during the lightning strike.
I post the exact comment here.
So, the voltage could go up to 500 volts, and the fuse will not open up.
Barnstars:
And this is the problem alone. Is the power supply in the equipmemt designed with a lightning strike in mind? Some yes, others, no.
There is no harm in having the surge suppressor along with the fuse in the circuit. The fuse will not open up until the current melts the link. This will take time, and in the interim, that jolt will get transmitted into the power supplies.
It seems Mohan does not understand the difference between a comment and an Answer.
Because the load is inductive, the current lags the voltage.(by a bit).
This one hit behind the barn.
Pro-AI Subreddit Bans 'Uptick' of Users Who Suffer from AI Delusions - 404 Media
(There is no concept of polarity, in the loop because the current changes direction 100 to 120 times a second (power frequency).
Can the fuse protect the electronic devices from lightning instead of a surge protector.
One
SpaceX launch from California sends 26 Starlink satellites into low Earth orbit - Space
a photo is worth a thousand words.
Edit 2024–10.
What does a fuse do?
This device then solves the entire problem.
When the current is 200% of the rated value , it will “go open” (the link metal melts) and protect the device.
It also is a device that limits the change in current flow.
But… the neutral is now “floating” because of the 1 ohm resistance.
“ A fuse is a device which protects the (circuit) against overload and short circuit.”
In schematic diagrams this is the symbol for a fuse:
Would individual surge supressors have save this equipment? most likely, since the surge supressor would take the jolt instead of the electronic components.
but I think this circuit , shows a few more pieces.
[old diagram got deleted by accident]
Upvotes:
So combined with a device called a MOV or Metal-oxide-resistor, then forms the 3rd part of a “surge suppressor “.
The MOV will conduct when the voltage exceeds 50% of line voltage.
2024–10–11 [Victor Olarewsju Victor Olarewaju ]
what exactly is a ‘surge’ protector?
There are three different concepts here that are getting confused.
He then describes the function of a fuse.
Now when you have a certain ac resistance, then a current flows in a loop.
(Dc diagram shown, AC is similar).
So, it’s possible that these devices from Trip Lite have addition suppression devices, these ones seem to be sturdy.
He then asserts :
He then describes Rainy Season and Lightning.
At one ohm, the resistor has a maximum of 1 watt power.
“ … to protect building, lightning arrestor, is provided above building and directly connected to earth.”
These are simplified answers to the original question, and does not change anything I wrote above.
so, what happens?
This is where this question deviates from being a 'generic' question, and becomes more specific.
An AC voltage/ current source, and an ac inductive load.
These devices are installed between the “hot” and “neutral” and protective ground.
This is where the MOV conducts again, and dissipated the energy.
2024–10–00 [ Ammar Mahdi ] Ammar Mahdi
At the secondary, it is 1000 times less.)turns ratio). If it gets hit with a 100,000 volt bolt of lightning then the voltage arrestors conduct and clamp the voltage down to line voltage, ( but a small amount leaks down the line). This is the problem.
This is a high voltage low current spike that comes down the line because of the power poles being struck, and the voltage suppressors activating on the primary side of the transformer.
the problem then depends on "how fast does the fuse operate?".
A circuit breaker is similar, but is resettable.
There are two important concepts here.
First Sentence:
This is the picture of an electronic coil of wire wound around a core of magnetic material.
But during the surge, the fuse will not blow if it is a longer duration and lower value )10 to 50%).
A fuse is a non-resetable over current circuit protector.
One is “what exactly is in a ‘surge protector’ ? ”