Strange rain water leak via mast wiring

[sinnerman]

I was lying in my boat, watching YouTube through an early morning downpour on Memorial Day, when I suddenly had water dripping on my feet.

Chasing the source, I found it was coming from one of my mast wiring cables (Steaming Light). The cable is Ancor flat duplex which has twin 16 ga. conductors inside a white vinyl sheath.

https://www.ancorproducts.com/en/p/1...-2-x-1mm-sq-Fl

Apparently, the water, being the sinister thing that it is, was traveling INSIDE the vinyl sheath flowing alongside the wires down the mast to its final destination of dripping inside my cabin.

I was amazed that this could happen, but then again water is sneaky.

Cheers.

[psk125]

Sounds like a drip dip in the wiring at the masthead might help. Wires entering the mast should be led down below the point where they enter the mast, and then up into the mast. Rainwater hitting the wire will tend to run down to the lowest point and fall off it, outside the mast. This setup is WRONG- rain hitting the wire will be led directly into the mast. https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAJ
This shows how the wire needs to dip down before it goes into the mast, to reduce rainwater infiltration: https://svyohelah.com/Boat/2006/Misc...astwiring2.jpg You can use binoculars to see what you have at the masthead.

[markxengineerin]

I heard about this same thing once before, so you're not alone.

I have accepted a small amount of leak through my mast wiring, two attempts to seal it were expensive, time consuming, and futile. Instead, I have resin coated all the wood from the entry gland down to the bilge (to prevent rot), and now water just drips harmlessly down and gets pumped out when enough accumulates. Mentioning this in case it's easier for you to "band-aid" the problem rather than really fix it!

[sinnerman]

Originally Posted by psk125

Sounds like a drip dip in the wiring at the masthead might help. Wires entering the mast should be led down below the point where they enter the mast, and then up into the mast. Rainwater hitting the wire will tend to run down to the lowest point and fall off it, outside the mast. This setup is WRONG- rain hitting the wire will be led directly into the mast. https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAJ
This shows how the wire needs to dip down before it goes into the mast, to reduce rainwater infiltration: https://svyohelah.com/Boat/2006/Misc...astwiring2.jpg You can use binoculars to see what you have at the masthead.

Mast wiring (new) was done by a third party. If the raw end of the cable at the steaming light was pointing downward instead of upwards, the water could never enter the cable.

I still find it amazing that there is enough space inside the two-wire cable for the water to find a path.

Cheers

[deblen]

The likely original cause is that the sheath of the 2 wire cable is not run inside of the light fixture,where it would be weatherproofed.Water would never get inside the sheath if this had been done.
Even then,leaving a proper drip loop,allows the water to drip off the sheath before it enters a hole in the mast.Water should never be allowed inside a cable sheath-it will bite you someday
A possible patch,if you have enough extra wire at point where it enters mast,is to form a drip loop with the sheath pointing down & the individual wires led lower,before turning upwards.Cut the sheath back if you have to.


Do you ever see house wiring with the sheath cut open before it enters the fixture??
Cheers/Len

[sinnerman]

Originally Posted by deblen

The likely original cause is that the sheath of the 2 wire cable is not run inside of the light fixture,where it would be weatherproofed.Water would never get inside the sheath if this had been done.
Even then,leaving a proper drip loop,allows the water to drip off the sheath before it enters a hole in the mast.Water should never be allowed inside a cable sheath-it will bite you someday
A possible patch,if you have enough extra wire at point where it enters mast,is to form a drip loop with the sheath pointing down & the individual wires led lower,before turning upwards.Cut the sheath back if you have to.


Do you ever see house wiring with the sheath cut open before it enters the fixture??
Cheers/Len

Most likely.

The guy who installed the mast wiring, should have had the cut end pointing downward , not upward inside the mast where it acts like a funnel.

The steaming light works (tested) so the at least light fixture itself is not filling up with water...

cheers.

[hjohnson]

This is why my mast wiring terminated in a potted multipin milspec connector. It’s completely waterproof (assuming the female deck connector is bedded properly). It’s worked beautifully over the past 8 years.

I use a 12 pin amphenol connector that has 4 large pins and 8 small ones. The large pins are used for the grounding, and nav lights, the small pins are used for the masthead wind sensor and potentially loudhailer.

[hpeer]

Yes, I have had this twice.

It is unlikely the water inside the sheath will cause damage.

The best solution is to seal the top so none gets in.

An alternative solution is to seal the BOTTOM so none gets out.

From painful experience the best sealant I have found is E6000. It grips the conductor insulation better than 5200 or liquid electrical tape, and remains amazingly flexible. Widely available in hardware stores and online. On Amazon it is advertised as glitter adhesive, but if you read up on it you will see it is industrial strength Shoe Goo.

The wire needs to he dry. Try to push it up inside the sheath. Once I had it done it worked for several years until I pulled the mast.