# Where best to place a fuse?



## mrsinbad (Feb 15, 2008)

OK, really dumb question, but may be I can get a quick answer. 

If I wanted to protect my electronic devices/circuits, should I place a fuse on the (+) or the (-) side of my power cord, and why? 

Thanks!


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## The_LED_Museum (Feb 15, 2008)

Technically, it really doesn't matter, but the favoured location of fuses, switches, or other power interrupting devices is on the positive (+) side.


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## chimo (Feb 15, 2008)

You generally don't fuse your neutral return line for safety reasons. If you are going to put one in, put it on your hot lead.


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## KC2IXE (Feb 15, 2008)

In a car (assuming negative ground) - it goes in the hot lead as close to the power source as you can

AC - in the Hot lead

Sometimes DC - Put one in BOTH leads


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## 270winchester (Feb 16, 2008)

all the fuses on my car that I added for my lights are right near the positive terminal of the battery. saved my butt quite a few times


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## z96Cobra (Feb 16, 2008)

It is a lot safer to fuse the positive wire. If it is on the negative wire, the positive is still hot even if the fuse is blown. 

Little analogy... Where would you rather have a shutoff valve on your home water system if your faucet is leaking, on the supply pipe to the sink, or in the drain pipe under the sink!


Roger


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## enLIGHTenment (Feb 16, 2008)

Always fuse the conductor that is at a potential with respect to ground. In DC circuits, this is the positive side. In AC, it's the hot wire or hot wire*s*.

Always place the fuse as close to the source of power (battery, power jack, etc) as possible. Minimize excess cord between the power source and fuse.

Getting either of these rules wrong can start fires or cause injuries because part or all of the device will be left without fuse protection.


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## VidPro (Feb 16, 2008)

enLIGHTenment said:


> Always fuse the conductor .


 
yup, what he said, or, how i would say it.
fuse goes BEFORE any shorting that could occur, even if it looks today like shorting cant happen there.

how long did it take Automobiles to put an inline fuse close to the battery, before running fat amps down the metal (-) frame for 4 feet to the "fuse box"


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