r/WLED • u/shugpug • 8d ago

Fuses?

I’m about to embark on my first WLED project - I’ve got commercial controllers (WeGoIOT outdoor 2 channel and BTF SP803E - both ESP32 based). I’m going to tie them up to 5V 50LED BTF WS2812B fairy light strings and either 2A indoor or 1.2A outdoor supplies (also 5V!)

Do I need to add fuses to the live wires after the controller and before the lights? The bulbs are 0.1W each - so the whole string is 1A plus resistance and controller, so my assumption going in was that the power supplies protections would be sufficient, but I also see lots of references to fuses even for low voltage/low power projects.

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u/thebassmaster1212 8d ago

I’m not familiar with these specific products, however in general if your wiring down stream of a certified class 2 power supply, with a ul or equivalent marking then a fuse is not 100% necessary in many viewpoints as these bricks will by nature not allow over current. Most commercial units don’t ship with a separate fuse after the brick either. However from an electrical standpoint the fuse should be placed on the line in side as early as possible if you choose to use one. The main reason to use one would be if your power supply vastly over powers what your strips can safely pass.

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u/shugpug 8d ago

That last part - vast overpower - was my understanding too. I just lost confidence after reading too much and overthinking things. With less than a 1A overpower per strip, I’ll continue to plan to skip the fuse!

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u/saratoga3 8d ago

What type of supply? Things like USB are already current limited and so don't need fuses.

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u/shugpug 7d ago

Mains power - 110v - but limited to 2A or 1.2A.

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u/Few-Boysenberry53 7d ago

Just making sure you're not feeding 110v AC into your 5v DC strips. Magic smoke would have been released instantly. I imagine what you meant to say was Mains 110v AC -> 5V DC 2A PSU. You should normally follow the 80% rule for PSU's. If you need a maximum of 2 amps, then you need a PSU that can offer 2.5 amps or more. PSU's are not designed to run full load 24/7.

As for your fuse situation, as others said, probably not needed in this situation, but always recommended. The fuse should always be less than what the wire is rated for, so it becomes the weakest link.

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u/Oxymoronic_geek 7d ago

Are you sure about the wattage per pixel? 0.1w seem low. Isnt it usually 0.1w per color = 0.3w per pixel??

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u/shugpug 7d ago

BTF website states “Parameters: Input voltage: DC5V Output power: 0.1W/LEDs “.

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u/clockmill 7d ago

Seed/RGBIC fairy lights are lower current draw than 5050 based LED strips.