Passing cables from tongue box into trailer when there is a small gap present

[JCDriller]

Normally, I'd be thinking of a PVC bulkhead connector with plenty of silicone, but my trailer has a 3-5mm gap between the tongue box and the front of the main cabin body so I'm not sure if there is a better solution. I need to pass a number of cables through while keeping it water tight. I'd love to have a 1-1.5 ID pass through. Anyone got any ideas on where to start?

 

[Adventurous]

Normally, I'd be thinking of a PVC bulkhead connector with plenty of silicone, but my trailer has a 3-5mm gap between the tongue box and the front of the main cabin body so I'm not sure if there is a better solution. I need to pass a number of cables through while keeping it water tight. I'd love to have a 1-1.5 ID pass through. Anyone got any ideas on where to start?

I would peruse either the West Marine or Heyco catalogs (https://www.heyco.com/Liquid_Tight_Cordgrips/). I'd think you should be able to find something in there that will fit your needs.

A wee bit more of a rudimentary solution would be to drill a hole through the tongue box and the trailer, pass a flexible piece of rubber tubing through, grommet/silicone at both ends, then run your cable bundle through that.

 

[JCDriller]

I've seen all those, I'm not so much trying to keep liquid out of the ends as I'm trying to keep it from penetrating from the gap into the trailer or the tongue box. I'm thinking about going with the PVC fitting below. I'll drill my hole, silicone the male fitting into the tongue box, bulk up the silicone between the box and the trailer, slide them together then put the nut on from inside the trailer with more silicone. This would give me more than adequate room to run cabling back and forth from the trailer to the tongue box, but I'm still open to other input and ideas.

 

[Bullseye240]

With three of those fittings you can take two of the nuts off, turn one of them around and use the last one to clamp to the second box. Basically start off as you described except install the fitting as originally intended, then install a second nut backwards facing the second box, once the bulkhead fitting is through thread on the third one same as the first and clamp the second and third one together. If that makes any sense. I have time tomorrow and I could go to the big box store and take a picture of what I mean if it would help.

 

[JCDriller]

With three of those fittings you can take two of the nuts off, turn one of them around and use the last one to clamp to the second box. Basically start off as you described except install the fitting as originally intended, then install a second nut backwards facing the second box, once the bulkhead fitting is through thread on the third one same as the first and clamp the second and third one together. If that makes any sense. I have time tomorrow and I could go to the big box store and take a picture of what I mean if it would help.

I know what you're saying, but I don't think here would be enough room between the box and the trailer. I think I'll have to just use a sealant like @Verkstad recommended.

Looks like you just want a watertight sleeve ?
Provided its long enough, That big PVC chasenipple sort of thing should work fine. You could simply use a nipple & locknuts.
If you fit it up all rigid, be sure there is no chassis flexing or otherwise motion between tonguebox & bodywork.
(Btw, actually not a chasenipple, appears to be a plumbing part of some kind...)
Fwiw, silicone can work, but its for chumps. Especially if joints must accomodate motion. Urethanes bond much better and greater selection of durometer hardness & elasticity.

Any particular brand of Urethane you recommend?