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### Topic: Fuse and wire gauge (Read 1 time)previous topic - next topic

#### stebod

#15
##### Nov 02, 2019, 01:40 pm
Quote
I take that to mean that if you short the output the current will be very low, and probably not blow a fuse.
Does that mean i dont require a fuse in the circuit?

#### SteveMann

#16
##### Nov 02, 2019, 02:06 pm
I take that to mean that if you short the output the current will be very low, and probably not blow a fuse.
That's called a Soft Fuse. The Power supply shuts down to protect itself, and when you remove the load and turn the supply back on, all is good.
I am usually so far out of the box that most people don't know what I am talking about.

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#### PerryBebbington

#17
##### Nov 02, 2019, 02:06 pm
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Does that mean I don't require a fuse in the circuit?
Good question.

If you short the power supply it will shut down, quite possibly before any fuse can blow. The danger is 40A into a partial short could easily start a fire. I think I'd go with the fuses; 5A to individual sections LEDs. A fuse won't do any harm and it might do some good.

You could short the furthest point of the tape from the PSU, then measure the resistance of the short at the PSU, with the wires disconnected from the PSU. If the resistance is more than:
5V / 40A = 0.125 Ohms, then you are at risk because the PSU could easily supply the 40A into a short at the end of the tape, the tape would go up in smoke and possibly your house with it.

#### stebod

#18
##### Nov 02, 2019, 02:29 pm
Quote
You could short the furthest point of the tape from the PSU, then measure the resistance of the short at the PSU, with the wires disconnected from the PSU. If the resistance is more than:
5V / 40A = 0.125 Ohms, then you are at risk because the PSU could easily supply the 40A into a short at the end of the tape, the tape would go up in smoke and possibly your house with it.
Im not sure how to do this and i think im in way over my head, i just want it to be safe and not burn my house down

#### PerryBebbington

#19
##### Nov 02, 2019, 04:18 pm

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I'm not sure how to do this and I think I'm in way over my head, I just want it to be safe and not burn my house down.
Just put the fuses in, 5A, close to the power supply.

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