Power injection and fuse zones

happenstance

New elf
Joined
Aug 31, 2020
Messages
7
Location
Leura
Friends, I want to know if I should cut the positive wire on all of my power-injected strings.

I want to abide by two recommended practices regarding the powering of pixel strings:
  1. Protect with a fuse every power run that leaves your enclosure; and
  2. When injecting power into a string of pixels, sever the positive wire if the injection run is protected by a separate fuse.
These 'rules' I've garnered from the excellent video on power injection by Bill Porter. Here's a link into the part of the video where Bill talks about 'fuse zones':
View: https://youtu.be/Jgjdz0Nbswk?t=1417


Since every power injection run will be fused and will join a pixel string that is also fused, it seems to me that I will always have to sever the positive wire on my power-injected pixel strings. Am I talking nonsense? Is my rationale faulty? I'm completely new to Christmas lighting, and also an electronics novice. Can you reassure me that I'm correct in my understanding, or else convince me otherwise? Many thanks for your anticipated help.
 
Last edited:

AAH

I love blinky lights :)
Community project designer
Joined
Dec 27, 2010
Messages
4,188
Location
Eaglehawk
The best practice is to sever the positive between power injection points. Personally I'm slack and don't tend to. I just add another power injection cable wherever I either find the volts are getting too low or I feel that there should be an injection point there. Both ways will work.
 

Dreamin

Full time elf
Joined
Dec 28, 2016
Messages
382
Location
Sunshine Coast
Friends, I want to know if I should cut the positive wire on all of my power-injected strings.
Makes sense to me. I'm doing my 5V mega tree off a receiver and only powering the first 50 pixels, then cutting V+ and power injecting with a separate fused wire from a F8 board at 100 (according to Bill's video power goes both ways so should be fine and then I'll inject the same method every 100 pixels). I'm cutting the V+ due to the separate fuses and the fact they protect the wire.

For a prop that has 202 pixels, I've opted to have one lead from the Falcon F16, and injected power at 100 and 200 from pixel 1. It will be perfectly fine for 30% brightness and only has one lead.
 
Top