Fusing the PSU


New elf
Nov 23, 2019

This is my first year on running a controller and Xlights. I have run a static display for a few years but have decided to take the leap into pixels. I'm only starting out small and just want to see if I'm heading in the right direction. This is my planned layout out at the moment. I know it's a mix of the 5V and 12V....but I already had the 12V in my display from previous years and haven't purchased the 5V side yet. I'm leaning towards a 5V display as it grows but not sure. Distances are going to be pretty close to the control box (less than 4m)

Fuses - is it best just for an inline fuse or is something like hexfuse the only way to go between the PSU and controller?
Cable - what is the best cable for joining between controller and pixels - I thought I had seen someone mentioning 6 strand security cable before?

Thanks for your help!

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Senior elf
Generous elf
May 6, 2010
Lithgow, NSW
I dont fuse when the cable goes direct to the controller as it's another voltage drop I dont need (5V here). I do fuse power injection points and other power out of the box. I also use 4sqmm cable between PSU's and the controllers at both handle the current and to avoid voltage drop as well.

I use 6 core 14/020 security cable (NOT 7/020 as I have seen way too many people buy recently) between controller and lights, 1 data, 2 positive and 3 negative, or 3 & 3 if power injection.


Retired Elf
Feb 9, 2020
West Central Ohio
I'd like to start by suggesting that if you have 12 volt devices and not yet purchased any 5 volt pixels that you continue with a 12 volt only configuration. Mixed voltage systems add a layer of complexity and/or confusion and in my opinion it is better to avoid that scenario.

Whether an inline or hexfuse between a controller and supply is somewhat a designer's judgement call based I think on what the supply is capable of, what is connected to it, and the power demands thereof. With a small capacity supply probably an inline fuse. If the supply is larger and can easily feed multiple devices some type of fuse block strategically fused so that if something happens all of the supplies capacity is not diverted towards a single device. It is also a good idea to research how a supply detects and handles overloads. A Meanwell LRS-200-5 for example overloads at 110% to 140%. That's 44 to 56 Amp above its 40 Amp rating.

String cables need to be sized properly for voltage drop relative to the controller to pixel distance and current draw (number of pixels and drive levels) if one powers the strings via the controller. That's typically something in the 14/16/18 AWG range. If not, that is Data and DC- only from the controller then a 2 conductor 22AWG give or take a bit is sufficient.