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Topic: Fuse recommendation (Read 285 times) previous topic - next topic

batata004

Hi,

I am powering my arduino with a 12v power supply (AC-DC) that I put in my 220V wall socket. It's an expensive power supply so it should be good, but not. Today I was playing with it and lots of sparks came from my arduino and almost caught fire in my table (leaving a big burned mark in my table) so I runned to my house POWER DISTRIBUTOR (I dont know how to say it in english) and flipped the switch so my entire house would be OFF cause I couldnt even get close to my wall socket to remove it from the wall.

Probably something went wrong with my power supply and I think if it was not a wood table I could be dead right now cause I was working right on the other side of the table.

So I think it's time to explicitly use a fuse. Do you recommend any fuse to put after the power supply before connecting to my circuit? If something goes wrong with the power supply and it starts sending AC with high voltage to arduino, will this fuse protect me?

Budvar10

#1
Oct 19, 2016, 07:25 pm Last Edit: Oct 19, 2016, 07:27 pm by Budvar10
Something wrong is with your power supply. Does it have a main switch? Also, it should have a built-in fuses.
And..., what is about the breakers in power distribution box? Works correctly? Maybe, something wrong with electric installation in the house.

The simplest solution is to use extension cord with power switch.
Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

batata004

My houe power circuit was not well done, the breaker in the general electronic board in my wall should have opened the circuit automatically, but that didnt happen. Surelly something is wrong with the electric installation of my house cause I already had other problems with mains (freezer and an air conditioning).

Anyawy, a fuse I think would help but I have no idea what to use. In the shop I went there is only AC fuse. Can I use it?

Budvar10

As I said, the power source must have main fuse first of all, or do not use it. However, in such situation you described, it seems to me to use of 'kill switch' as the best solution. Power cord with switch would be the cheapest.
Don't forgot the regulations in your country.

Provide the link for AC fuse you talking about.
Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

DVDdoug

#4
Oct 19, 2016, 07:54 pm Last Edit: Oct 19, 2016, 07:59 pm by DVDdoug
A short on the low-voltage DC side of the power supply shouldn't cause excess current on the 220VAC side.    A well-designed power supply should have an internal fuse or some other protection.

Quote
In the shop I went there is only AC fuse. Can I use it?
Yes, a 220VAC fuse can be used with 12VDC.   The fuse's current rating should be slightly higher than the power supply's output current rating (so it only blows when you exceed the rating of the power supply).

Typically you can find low-current fuses (and inline fuse holders) where they sell electronic components (resistors, etc.) or maybe where they sell automotive parts.


Quote
...will this fuse protect me?
No!    A fuse limits the current but not the voltage...  Less than 1 Amp through your body can kill you!   220VAC with a fuse is still dangerous.

The main purpose of a fuse (or circuit breaker) is to prevent a fire.   If there is a short (or otherwise too much current) the fuse blows breaking the circuit so there's no more voltage or current and no heat or smoke, etc.



Quote
If something goes wrong with the power supply and it starts sending AC with high voltage to arduino,
If you think that happened, throw that power supply in the trash!      Do you have a multimeter?   With a multimeter you can check the voltage between the power supply outputs and the earth-house ground and/or you can check for continuity between the AC & DC sides of the supply (it should measure infinite resistance).


batata004

Yeap, I will buy another power source but even with the new power source I will do as you said, I will use a fuse with really low current cause this scaried me!

I dont know where I bought this power source but I paid about $ 20 (conversion from brazilian currency which is R$ 80).

allanhurst

May I suggest that you find a skilled electrician to examine your house wiring?

if faulty this could be dangerous..

regards

Allan

batata004

Yeap @allanhurst it would be right, but I am out of money. A friend of mine made the circuitry of my house and he was studying eletric engineering in a good university here in my state and he charged cheap. Now he is graduated and already has a job so I probably wont have his help for cheap anymore :(

gpsmikey

There is a big difference between studying EE and understanding/knowing the code for house wiring. I have seen lots of very strange (and dangerous) things done by people with some basic knowledge - for example, in the DC world (automotive etc.) the black wire is usually ground.  In the AC world (at least in the US, the black is the HOT wire and white is the Neutral wire in a 110v system - a friend of mine found most of his house wired backwards that way.  Typically, you can buy a cheap version of the wiring code (at least here in the US) at the local hardware store with a title of "basic house wiring" or something like that.  Get that and a multimeter and check to see if your house is wired the way it should be - not having the money to verify the wiring is a good way to burn your house down (which is much more expensive - especially if someone dies).

mikey
mikey
-- you can't have too many gadgets or too much disk space !
old engineering saying: 1+1 = 3 for sufficiently large values of 1 or small values of 3

TomGeorge

#9
Oct 20, 2016, 03:45 am Last Edit: Oct 20, 2016, 03:46 am by TomGeorge
Hi,
What failed?
Is your Arduino destroyed?
Is your power supply destroyed?
Do you have a DMM?
Can you post a picture of your Arduino and a picture of your power supply?

Thanks.. Tom... :o
Everything runs on smoke, let the smoke out, it stops running....

DrDiettrich

To prevent your next Ardunio from releasing the magic smoke, check your wiring and make sure that no conductive material sticks to the bottom of the Arduino board. Also disconnect any other devices from the board, which may introduce mains voltage to the board.

Does if work if you power a (fresh) Arduino from USB or batteries?

Budvar10

May I suggest that you find a skilled electrician to examine your house wiring?
if faulty this could be dangerous..
regards

Allan
I must fully agree with Allan. You will buy a new power source and the result can be the same. Your priority would be to repair your house wiring. According your description, I think it is life threatening. I understand that no all people on the planet have same living conditions like people from EU or US but consider that the life or health are indispensable.
Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

batata004

Thank you all for the suggestions, I cant get a loan only to change my house wiring, I have more important things to do, like eating and paying my kid school. Anyway I will study at google how to make a wiring in a house and I will do that by myself, using the correct wiring colors to not make any stupid thing like the guys you said here did!

Budvar10

Surely there some better focused webs to this problematic on the internet and exactly for your country/region specifics.
Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

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