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: 02.07.2025 00:43

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.
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.
what exactly is a ‘surge’ protector?
a photo is worth a thousand words.
This device then solves the entire problem.
Is the question then , "why buy a surge supressor, if the fuse alone protects the electronic circuits from a lightning bolt?".
Edit 2024–10.
First Sentence:
One
Russia’s central bank cuts interest rates for first time since 2022 - Financial Times
Fuses, on their own, then operate much slower than the MOV variable resistance, during the lightning strike.
Mohan forgets that a fuse is a one-time device, and needs to be replaced if it is tripped.
Barnstars:
What is the difference between Michael Corleone’s marriage to Apollonia Vitelli and Kay Adams?
Here is a simplified AC power diagram.
2024–10–00 [ Ammar Mahdi ] Ammar Mahdi
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.
Anger as Kanye West to perform in Slovakia after Hitler song - France 24
At one ohm, the resistor has a maximum of 1 watt power.
The other is “what does a “fuse” do?”
So combined with a device called a MOV or Metal-oxide-resistor, then forms the 3rd part of a “surge suppressor “.
Princess Peach's Voice Actor Has Been Replaced After 18 Years - Nintendo Life
“ 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”
“ A fuse is a device which protects the (circuit) against overload and short circuit.”
(Dc diagram shown, AC is similar).
Former church in Northern Kentucky now a heavenly home for sale - WWMT
What is lightning?
There are three different concepts here that are getting confused.
But during the surge, the fuse will not blow if it is a longer duration and lower value )10 to 50%).
Mars Orbiter Captures Rare View of Ancient Volcano Poking Above the Clouds - Gizmodo
What does a fuse do?
(There is no concept of polarity, in the loop because the current changes direction 100 to 120 times a second (power frequency).
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.
Xbox Game Pass adds The Alters today - TrueAchievements
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?
One is “what exactly is in a ‘surge protector’ ? ”
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.
Kanye West Shows Up At Sean 'Diddy' Combs’ Trial—And Quickly Leaves - Forbes
2024–10–11 [Victor Olarewsju Victor Olarewaju ]
eight
Because the load is inductive, the current lags the voltage.(by a bit).
How do you raise well-behaved children?
This is the picture of an electronic coil of wire wound around a core of magnetic material.
And this is the problem alone. Is the power supply in the equipmemt designed with a lightning strike in mind? Some yes, others, no.
but I think this circuit , shows a few more pieces.
“ … to protect building, lightning arrestor, is provided above building and directly connected to earth.”
He then describes the function of a fuse.
So, it’s possible that these devices from Trip Lite have addition suppression devices, these ones seem to be sturdy.
Your Blood Test Can Now Track Junk Food Consumption - Indian Defence Review
But it can get overloaded, and no longer works.
If the nominal power is 4,000 watts then the current at 230volts is 16 amps.
He then describes Rainy Season and Lightning.
the problem then depends on "how fast does the fuse operate?".
P = e* I, so since I is 16 amps, then the voltage dropped is 1/16 volt or 0.0650 volts.
2024–10–10[John johnson John Johnson ]
Giant Inland Boulder a Remnant of Ancient Tsunami - Newser
At least they know the answer if they wanted it.
2024–10–11 [Bobby Sanchez Bobby Sanchez ].
This is 'the assistant's answer'
2024–10–14 [Omar Gharbi Omar Gharbi ]
Upvotes:
Now when you have a certain ac resistance, then a current flows in a loop.
A circuit breaker is similar, but is resettable.
It seems Mohan does not understand the difference between a comment and an Answer.
[old diagram got deleted by accident]
but this device (an Inductor) … impedes the rapid changes in the current.
I post the exact comment here.
Can the fuse protect the electronic devices from lightning instead of a surge protector.
The third is lightning and “how it gets conducted into a home.”
An AC voltage/ current source, and an ac inductive load.
So, the voltage could go up to 500 volts, and the fuse will not open up.
A fuse is a non-resetable over current circuit protector.
nine
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.
2024–10–16 [ OO OLAOYE OYEBODE ]
The bolt then partially travels down the line to your home.
It’s been three xxx five werks, and there has been no response to my follow on query on his Commment to my answer.
[image of Common-mode choke]
It also is a device that limits the change in current flow.
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.
so, the loop of wire then, when put together with another loop reduces the ‘noise’ on a power line.
He then asserts :
This is where the MOV conducts again, and dissipated the energy.
When the current is 200% of the rated value , it will “go open” (the link metal melts) and protect the device.
The MOV will conduct when the voltage exceeds 50% of line voltage.
But… the neutral is now “floating” because of the 1 ohm resistance.
This one hit behind the barn.
This is where this question deviates from being a 'generic' question, and becomes more specific.
OK, this is Mohan Rajaratnam’s definition of a Surge suppressor.
Would individual surge supressors have save this equipment? most likely, since the surge supressor would take the jolt instead of the electronic components.
In schematic diagrams this is the symbol for a fuse:
For this case there are devices called Metal oxide varistors (MOV).
These devices are installed between the “hot” and “neutral” and protective ground.
so, what happens?
These are simplified answers to the original question, and does not change anything I wrote above.
There are two important concepts here.