Best way to make waterproof power injection cables?

[BundyRoy]

I normally use 3 pigtails. Solder the joins, then heatshrink each cable individually, then heatshrink over the lot. I'm concerned about the seals as the heatshrink doesn't slide over the two cables very well in the 3 cable join and then I use silastic to get seal on the two pigtails but always worry about that leaking over time. Any better ways. Thanks.

 

[David_AVD]

When I make Y cables I often put a zip tie on the double cables past the heatshrink to keep it from spreading and cracking the silicone seal.

 

[bbayjohn]

sounds like you are doing it right. Maybe a smaller diamater heatshrink. I like to use clear, makes it eaasy to inspect joins. You could put a layer of almagamating tape followed by electrical tape if you are worried.

 

[the grinch]

Once again me being different !
All of my power injection is totally un waterproofed !
My power injection is totally separate from the data etc .
I use automotive connectors and as long as positive can't touch or short between negative ! I really don't see the point of waterproofing !
Example of will be the engine bay of your cars ! which you can degrease and wash successfully . And obviously anything important is definitely waterproofed plugs
Also great tip ! Your local auto recycling yard or wrecking yard is great place to source plugs inexpensively .
But dont go cutting plugs off of useful parts they can sell ! May upset someone

 

[videoman3857]

I solder and heatshrink each wire and use resin filled heatshrink over the group of wires.