What wire and type of sealant

[sulrich]

What wire or technique do you use?

I use monoprice Access Series CL-2 16-4
https://www.monoprice.com/product?p_id=4041

i had water intrusion at some point. 15 strands of my megatree were bad this year.
very flakey, blinks, or just stay on white.
When i cut open the shrink wrap the smell of mildew hit me in the face. when i stripped wires back i saw the copper was black.. no longer had the copper shine. cant solder it to fix it. i threw out 15 pigtails that failed due to water infiltration. i use on every screw together pigtail a thick silicone based Dielectric grease, and it works great. the connector ends look new, but the internal wire is black.

i thought i was using quality shrink wrap. i was wrong. learned the hard way.
Buy nice, or buy twice!
This year i have converted to marine-grade dual-wall heavy duty adhesive lined shrink tube ($0.80 per foot)..
Another new practice i started was shrink from the center out to the ends, but when 1/2" away from the end i stop. I take my hot glue gun and put a few pumps in each end. then when i hit it with the heat gun to finalize the shrink, the excess glue is squeezed out, filling all cracks and crevices at each end. o far so good.

Steve

[arw01]

Hot glue contracts and expands and therefore cracks.

I have had a string or two start with the black corrosion.  I tossed em, as it just keeps happening, like an infection almost.

Pretty much now just crimping on the connectors and they have the heat shrinking tubes already with adhesive and low melt solder in the middle.

[ozaz]

agree with @arw01 hot glue not so good in the weather. A good dob of silicone, making sure it's a neutral (non-acid) curing type, on the ends of glue lined heat-shrink should do the trick.

[RandyS]

3:1 Adhesive Lined Shrink Tube will do the trick.  You might also try Stranded Cat5 or 6.  It is MUCH cheaper and can carry data much further than most 'cable'.

[danj]

I went ahead and overkilled my cables this year-I used the heat shrink crimps then put heat shrink over both ends of the connection--the connector and the cat5 cable--same reason as you stated--I had lots of glitchy stuff going on with my megatree that I believe was mostly due to water intrusion--when I took the tree down some of the cat5 cables still had water in them and it hadn't rained for weeks.  I use cat5 cable and have found it to be a really good "fit" for this application.  I had a controller failure last year and had to run a 55' run from another controller (across my driveway--arrgh) and it worked perfectly.