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Author Topic:   Trailer Wiring Connectors
L H G posted 09-10-2009 04:59 PM ET (US)   Profile for L H G  
For trailer wiring connections, NOTHING works as well as a properly sized wire nut, with wires going into the nut properly stripped and snap tied, filled with Boat Life waterproof sealant. Those connections will last the life of the trailer, have no bare wire exposed, and are not compromised by dunking in salt water.
jimh posted 09-13-2009 09:28 AM ET (US)     Profile for jimh  Send Email to jimh     
[Separated from another discussion about connectors for other purposes.]
jimh posted 09-13-2009 09:38 AM ET (US)     Profile for jimh  Send Email to jimh     
I suspect that a butt splice connector with adhesive heat shrink will work well in a trailer.

I am not at all fond of applying sealant or caulk to electrical wiring. My objections are on these concerns:

--the curing process of the sealant is lengthy, often several days;

--the curing process of the sealant my produce acidic residue which can corrode the electrical connection;

--once the sealant is cured, the connection is difficult to repair or service, as removing cured sealant can be difficult;

--application of the sealant is generally messy;

--small containers of sealant are rather expensive, often costing more than a collection of adhesive heat shrink marine-grade butt slice connectors.

I am not at all fond of using household wire nuts for exposed electrical connections. Most wire nuts are designed for solid conductors, not stranded conductors. Tightening a wire nut on finely stranded wire often causes strands to break off. Wire nuts are bulky.

Were household wire nuts and caulk sealant a good solution to the problem of making a connection on a trailer, you would expect that some OEM trailer manufacturers would be employing them. I do not recall seeing any boat trailers wired in this manner by their manufacturers.

The wire nut and caulk sealant solution is certainly something that can work, but I do not think it is superior to other wiring practices. The best practice in wiring on a trailer or equipment which is likely to be immersed in water is to avoid making any splices.

L H G posted 09-14-2009 01:38 AM ET (US)     Profile for L H G    
I've been dunking trailers into saltwater for over 40 years, and have tried all of the common wiring methods, all of which quickly corrode and fail, and none work as well as the silicone encapsulated wirenuts. They ended my problems for good. That's simply my experience, and I can't even take credit for the idea. It came to me from Clark Roberts.

I admit, these connections aren't necessarily pretty, and I don't use them anywhere on the boat unless it's a connection that continually would get wet, such as for a bilge pump float switch. Most trailers that I have seen HAVE to have splice connections, because of the side marker light requirements on fenders and and trailer frames, and the stern light bar. Trailer manufacturers tend to use those horrible blue press-on splice connectors, that quickly corrode and fail. They're not pretty either, and the cheapest and quickest solution. That's all that seems to count in boat trailer manufacturing. For side marker light wiring, you can run the necessary three wires into the plastic wirenut easily, and then seal it up. About 1/2" outside of the nut, I put a tie wrap around all the wires going into it to eliminate any pull on the connection.

Try it, you'll like it!

jimh posted 09-14-2009 08:59 AM ET (US)     Profile for jimh  Send Email to jimh     
I agree that the in-line press-on blue splice connectors often seen on trailer wiring are not a good solution to making circuit connections, particularly on lamps near the rear of the trailer which are always submerged during launching and loading.

The best way to avoid problems with electrical circuit splices is to not make any. Run individual wires from all the lamps to a central point on the trailer, and use a point which will not typically be immersed in water. Join the various lamps on the trailer together at this point, and connect them to the trailer-to-truck wiring harness. This avoids all spices in the wiring.

On my present trailer, I am using a molded aluminum box that is mounted to the trailer frame near the tongue as a central wiring point. I thought I had the box mounted far enough forward that it would never get wet. Recently when launching from a very shallow ramp, I had to back in the trailer much farther than normal to get the boat to unload. I noticed my wiring box was much closer to the waterline than I expected. If I were to do this again, I would mount the wiring box on the winch stand to get it even higher.

Tom W Clark posted 09-14-2009 12:00 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Caulk filled wiring nuts is a perfectly acceptable method of making a water proof connection. It is has been used of years for low-voltage landscape lighting where connections need to be buried.

They eve make special extra large wiring nuts pre-filled with a waterproof grease for this application. I would not use these on a trailer, however.

The trouble with the caulk filled wiring nut is that it makes a large and ugly connection. While I agree that Larry's idea of using a tie wrap to take the strain off the wiring nut itself is helpful, it still puts a sharp 90 degree bend on the wires if the wire is ever tensioned.

The large size will also make it difficult to pull though an opening or down a trailer tube.

A much better connection method is to use the adhesive filled heat shrink butt connectors make by ANCOR. These are perfectly waterproof, more waterproof, in fact, than the wire itself.

They also offer a small diameter connection and one that has the wire aligned correctly for strain relief.

davej14 posted 09-15-2009 02:15 PM ET (US)     Profile for davej14  Send Email to davej14     
The gel filled wire nuts would be a better option than filling them with caulk. The gel is designed to displace water from the connection, not just prevent encroachment.
Chuck Tribolet posted 09-16-2009 09:57 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Connectors? I don't need no stinking connectors.

Ancor marine-grade wire, soldered, and covered with Ancor
hot-melt-glue-lined heat shrink. The only connctors on the
trailer are the flat-four at the truck, and another flat-four
tucked way up inside the winch stand (so that when the
flat-four at the truck fails mechanically from being plugged
and unplugged 100+ times a year, it's really easy to


jimh posted 09-18-2009 10:58 PM ET (US)     Profile for jimh  Send Email to jimh     
I would give a lot of weight to Chuck's recommendation, based on Chuck's very high use of his trailer in saltwater ramp launching and loading. I suspect that Chuck backs his trailer into saltwater far more times in one year than anyone I can think of. People who keep their boats at a dock really don't use the trailer for launching and loading that much, perhaps just a few times each season.
contender posted 09-19-2009 04:25 PM ET (US)     Profile for contender  Send Email to contender     
Chuck is correct, this is the best way to connect any/all wires use for your boat or trailer. This has been the only way I make any of my connections...
Moe posted 09-20-2009 03:25 PM ET (US)     Profile for Moe  Send Email to Moe     
I also use tinned marine wire with soldered splices covered with Ancor glue-lined heat shrink. But I also covered the soldered joint with liquid electrical tape and allow that to dry before sliding the heat shrink tubing up over it. Belt and suspenders.

I don't use the trailer frame for a negative bus, but instead run black insulated tinned wire to each light and make those connections as waterproof as the positive leads.


HAPPYJIM posted 09-20-2009 08:27 PM ET (US)     Profile for HAPPYJIM  Send Email to HAPPYJIM     
These work quite well for splicing that goes under water.

Chuck Tribolet posted 09-21-2009 12:33 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
For the record, my trailer gets dunked in salt water about
140 times a year (70ish days, launch and retrieve each day).

BTW, my truck also has the "flat-four extension cord" trick.


Don88outrage posted 09-21-2009 12:06 PM ET (US)     Profile for Don88outrage  Send Email to Don88outrage     
If Dave is referring to silicone gel, the non hardening grease type, not RTV, I have to agree. When cable TV first came out a good friend who was a cable installer gave me a couple tubes, he said they use it on all their weather exposed connections . Been using it on all electrical connections ever since, wiring connections, electronics plug in's, spark plug connections, trailer connection plugs, battery connections It insulates, lubricates and reduces corrosion, great stuff.
17 bodega posted 09-22-2009 01:32 AM ET (US)     Profile for 17 bodega  Send Email to 17 bodega     
With regard to Chucks recurring theme of eliminating connectors:

Do you solder or screw the ground wire to the chassis at the "wet" end of the trailer or run (splice) all the grounds back to the white lead on the flat four?

Additionally, what method do you connect the wire before you solder the connections? A splice style weave of the two wires? Twist them together and fold the end back before covering? I have always struggled with the best way to accomplish this. No matter how well I shrink tube, solder, splice, liquid tape, etc, I get the corrosive wire cancer within a year.

I just replaced my tail lights for the umpteenth time with a set of "dry launch" and all is good for now. Fingers are crossed! (by the way, dry launch light do NOT have tinned copper!! Won't these guys ever learn?)

In conclusion, it seems that even if you bypass the use of connectors, you are still mimicking its effect with the solder and tape/shrink tube process. Are the stinking connectors really the problem? Is it the oxygen that is trapped in the air spaces of the connector that eventually fail and cause corrosion?

I don't launch as much as Chuck, but I'm pretty close. I work at a saltwater boat launch facility and in a months time, I will launch up to 10 times, sometimes twice a day. I unplug before launching, and rinse with fresh water at the end of the day. My trailer was rewired two yeas ago with all tinned ancor "4 wire" trailer wire in the white housing.

L H G posted 09-22-2009 02:10 AM ET (US)     Profile for L H G    
17 - You'll be very satisfied with the Dry Launch lights. They last and last. Try my wire nut suggestion. You'll see what I mean.
PeteB88 posted 09-25-2009 11:27 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Could you pot them in epoxy? Too much heat?

I have dabbed liquid electrical tape on connections after soldering. Where do you get Ancor connections?


Tom W Clark posted 09-25-2009 12:05 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
The ANCOR adhesive lined heat-shrink butt connectors are as strong and as watertight as the wire itself. Why fool with anything else?

I use them on my own 20 year old galvanized trailer. Not one has yet failed in the five years of saltwater use since I installed them. I do not disconnect my wiring when I dunk my trailer.

ANCOR adhesive lined heat-shrink butt connectors are available just about anywhere boating supplies are sold.

Chuck Tribolet posted 09-25-2009 04:30 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
All the grounds go back to the white connector on the plug.
They all come together up inside the winch stand so they
don't get wet much. IIRC, there are 8 wires coming together.
It was everything my 300W soldering gun could do to get it
hot enough.

I just twist the two wires together, with the insulated
part going in opposite directions. There's no overlap of
wire A with wire B's insulation, just the bare parts of the
two wires.

I think it's the salt that causes the problems. The hot melt
glue seems to keep it away.


andygere posted 09-28-2009 02:35 PM ET (US)     Profile for andygere  Send Email to andygere     
For what it's worth, the lights on the trailer under my '89 Outrage Cuddy are wired by a previous owner using, gulp, wire nuts with some type of sealant inside. This was a detail I planned to "correct" soon after I purchased the boat, but the lights worked flawlessly, and there are always other projects that need doing. Some six years later, the rather clunky looking connections are still going strong, and I've never had any problems with them, so the wire nuts stay. Also, I never disconnect the lights from the truck when launching or retrieving. What's the point of doing that?
17 bodega posted 09-28-2009 08:57 PM ET (US)     Profile for 17 bodega  Send Email to 17 bodega     
If the wire nuts Andy and LHG are talking about the blue ones you can buy by the bagful... I have a bag of them. I haven't used them yet, but it sounds like they stand up. The next time I am forced to do trailer wiring, I might try the ANCOR hot melt glue Chuck speaks of as well. I'm sure the wire nuts are good as long as the goop stays in there.

The DRY LAUNCH lights are very nice. I'm impressed so far.
I'm still paranoid from past experiences, so I disconnect before dunking.


L H G posted 09-28-2009 10:01 PM ET (US)     Profile for L H G    
The Dry Launch round tail lights on one of my trailers are 20 years old, and I have never disconnected them before launching.

Be sure to replace the 1/4" x 1" carriage bolts that hold them on with SS versions, including washers and nuts. Otherwise they will rust, and you won't be able to remove the lights for cleaning or service. Only weak link in the product!

jimh posted 09-28-2009 11:01 PM ET (US)     Profile for jimh  Send Email to jimh     
More on DRY LAUNCH tail lamps:

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