HELP - Water proof wire connection

[garage nut]

With winter right on us I realized that my driveway lights are out. Getting home at after sunset and lights on a daytime switch.

When I installed them some 5 years ago I used what we call thin and earth cable...1.5mm sq is good enough to drive the 6 x 60Watt globes spaced equally distant down the drive way.

Upon investigation I found moisture had gotten into the joints where I tapped off to run a supply to the individual lights. On hind sight I should have taken the cable up the post and made the joint above ground at the light fitting, but for now I am stuck with having to mage the joint at the base of the post and subsequently partially under ground.

I used valcanising tape to ensure a waterproof joint but clearly this could not stand the test of time.

I need some proven ideas how to make a lasting waterproof joint. the wire is a single strand copper wire, 1.5mm sq

[olderdan]

With winter right on us I realized that my driveway lights are out. Getting home at after sunset and lights on a daytime switch.

When I installed them some 5 years ago I used what we call twin and earth cable...1.5mm sq is good enough to drive the 6 x 60Watt globes spaced equally distant down the drive way.

Upon investigation I found moisture had gotten into the joints where I tapped off to run a supply to the individual lights. On hind sight I should have taken the cable up the post and made the joint above ground at the light fitting, but for now I am stuck with having to mage the joint at the base of the post and subsequently partially under ground.

I used valcanising tape to ensure a waterproof joint but clearly this could not stand the test of time.

I need some proven ideas how to make a lasting waterproof joint. the wire is a single strand copper wire, 1.5mm sq

You probably know this already but that vulcanizing tape has to be stretched to 2 thirds of its width to seal properly, I would redo the joints the same way and add a silicone tube injected with low modulus silicone as a cheap fix , there are underground jointing kits but they are quite expensive.

[garage nut]

Yip know that I have to stretch it.

I have seen the kits but like you said expensive and I have 4 to do just for starters.

[Crusty]

Paint the connections with liquid vinyl before and after taping, then cover it with a protection type tape (like Bulldog) and paint it again. Alternatively, you can pot the connections in RTV silicone but it may take days to fully set.

If you solder the connections then moisture isn't as much of a problem with low voltage wiring.

[Frank S]

I would think the first step will be to kill the corrosion. Not as easily done as some may think. I have had god success using a product made by KBS coatings but others are available the Rust Blast when used as directed will kill and remove corrosion but should be neutralized afterwards on copper electrical and aluminum and brass.
But this would be true for moat any corrosion dissolving solvent.
Then what I have done in marine applications before making connections I would slide lengths of shrink tubing on each individual wire then slide a larger piece of shrink tubing with dielectric coating on the inside over all of the wires tightly twist the clean bare ends of the wires together and fold that back on itself when possible then use an electrical solder paint the connection with more dielectric grease as I call it . slide all of the shrink tubes up as far as possible and slide the larger covering tube over all of these then heat the large shrink tube will bond with the smaller ones the smaller ones will bond with the wires and the insulation. the reason for the small individual tubes is they will form a bond between each other removing any possibility of exposure to air or moisture between the wires where as the single large cover tube can not do this by itself when 2 or more wires are entering from 1 end. On Aa running splice connection with only 2 wires a single cover tube can make a sealed bond.
There is another simpler way to make a lasting seal which is by using the dip-it liquid rubber type product you see advertised for making non slip grip handles on hand tools. This only works for end type connections not running splice. you dip the connection into the rubber allow it to cure then dip it a second time and a third if you feel it is required. once fully cured it will be a durable air and moisture tight covering.
Hope some of this helps

[nextofkin]

With winter right on us I realized that my driveway lights are out. Getting home at after sunset and lights on a daytime switch.

When I installed them some 5 years ago I used what we call thin and earth cable...1.5mm sq is good enough to drive the 6 x 60Watt globes spaced equally distant down the drive way.

Upon investigation I found moisture had gotten into the joints where I tapped off to run a supply to the individual lights. On hind sight I should have taken the cable up the post and made the joint above ground at the light fitting, but for now I am stuck with having to mage the joint at the base of the post and subsequently partially under ground.

I used valcanising tape to ensure a waterproof joint but clearly this could not stand the test of time.

I need some proven ideas how to make a lasting waterproof joint. the wire is a single strand copper wire, 1.5mm sq

About 25 years ago the wire that runs the well pump was cut about 50 feet down the well (it was under water) I spliced it with wire nuts after I cleaned it real good than packed wax in and around the wire nuts than wrapped it with electrical tape it lasted about 10 years until the pump was changed.

[Toolmaker51]

You could inexpensively duplicate the intent of underground kit with small plastic prescription bottles. Drill one or two adjacent small holes in the bottom and extend the ends out a ways to complete the connection. Make up all 6 this way. Fill the canister about 2/3rds full of common silicone starting at the bottom, draw the wires back into container, displacing some of the silicone. Let them set and put on the cap.

[Frank S]

You could inexpensively duplicate the intent of underground kit with small plastic prescription bottles. Drill one or two adjacent small holes in the bottom and extend the ends out a ways to complete the connection. Make up all 6 this way. Fill the canister about 2/3rds full of common silicone starting at the bottom, draw the wires back into container, displacing some of the silicone. Let them set and put on the cap.

That would do the trick for sure as long as the connection was good clean and tight because it is going to be next to impossible to in pot it once the silicone sets up but this would be true for any of the previous suggestions
Another reason why I should be saving the wife's prescript bottles

[garage nut]

Could normal resin (2 part type used to patch and fix boats) not also work. Could then tape up the end of the medicine container and just pour in the other. Depending on the mix ratio it can be usable in 15 minutes? or is there a specific reason silicone is the preferred sealant.

[Frank S]

Could normal resin (2 part type used to patch and fix boats) not also work. Could then tape up the end of the medicine container and just pour in the other. Depending on the mix ratio it can be usable in 15 minutes? or is there a specific reason silicone is the preferred sealant.

If you use potting resin your are golden but I would imagine that most anything that perfectly seals out any possibility of moisture intrusion would work just as well