How can I shield these electrical connections?

As you can see from the pic, this box is under the hood. I had to install a fuse box and relays in order to run the headlights and the power windows. The old stuff just kept failing and wasn't really up to the task anymore. Also I wanted a few extra relay and fuse slots on hand, for future upgrades. But as you can see, some of the connections are... kind of exposed under the hood. It's conceivable that dirt, fluids, and various other nasties might make it to these exposed connections.

How would you go about shielding them? There is a clear plastic cover over the top, but I'm a bit concerned about junk finding it's way in through the sides. The sides are just exposed to the engine bay. When I installed it, I made sure the whole thing can be easily removed. So that's not really a problem here. I wanted to be able to quickly detach it in case I needed it out of the way.

But I didn't really consider dirt and grime getting in there, underneath those clear plastic covers you see in the first pic. Now the more I look at it, the more I want to seal it off somehow. 1987 Silverado if that matters. Thanks!

Liquid electrical tape

Soldering the wires to the connectors (eyelets) and running shrink wrap would have been better than the crimp connectors in terms of protecting the wires overtime.

Assuming you want to protect the actual screw terminals I'd probably cover them in a good layer of dielectric grease. Yes, dirt and stuff will get on the dielectric grease, but it's easily wiped away or cleaned away with a little electrical cleaner. Liquid electrical like Al suggests is a good idea to, but the down fall for me anyway is that stuff is messy and has to be scraped up / peeled off anytime you need to turn any of the screws in the box. I think both ideas have pluses and minuses.

Most times I will mask off stuff when using liquid tape to visible connections otherwise it looks crappy. Dielectric grease I use on connections I'm pretty sure I'll be working on again. I keep both in syringes.

I would get some square plastic square tubing, cut 1 side out so you now have 3 sided deep plastic channel,mount it under the junction blocks,legs pointing up,now fabricate a cover how ever you choose plastic,more plastic tubing,aluminum,use your imagination. You can probably rob some from some old shelving. Well just found some pre-made probably cheaper than you can make.

Most water tight enclosures will hold moisture. Hand Held Radios rated for IP67 or IP68 are known to hold condensation and short out.
The one's not rated, are useless for accidental drop in the water... It's a paradox...

Many a Mariner has grabbed the handheld needed for rescue, only to find out it was dead from moisture invasion.

Waterproof boxes are a myth, unless you pull all the air out and insert silica gel, like your double pain sliding glass door or windows have, in the aluminum extrusions, with pin holes. There's silica in the tubes of aluminum to keep the moisture from forming inside the vacuum.

Grew up soldering everything, after I got the Radio Shack Soldering kit...

The problem is:
Solder joints will crack around salt water humid conditions, such as near the beach... most Marine applications do not recommend solder anything. They break at the solder joint from corrosion. There's a lot to be said for high quality heat shrink crimps, too. When salt corrosion breaks your power wires, you have a fire behind your dash or under your hood, from vibrations cracking the wires at the solder. Just sayin'...

Soldered joints can be isolated... and I'll get to what works, if you have to solder later...

My truck has a 600A Buss-bar on the firewall.

Removed the A/C box and coil, so it left room to utilize the upper firewall section and drape my wires straight down from my buss bar, before bending and routing to the batteries. Used a sheet metal plate and a rubber gasket. Then riveted the hole closed, where the A/C crap used to live.

The hood gasket seal, at my firewall, is much drier than mounting on the fender wall, where I get water and snow creep in, under the sides of the hood.

That said, this fix will probably work on the inside fender, as well:

Mounted the buss-bar to a 3/8" slab of rubber, (5"x7" Mud Flap) so the rubber slab bolts vertical/parallel, directly to the fire wall.
The buss-bar mounts horizontal, to the rubber, around 1-1/2" below the bolts to the firewall.

Before I mounted the mud flap to the firewall, I found an old tractor inner tube and sliced it into a 12" wide strip, around 24" long.
|| <--fold where inner tube is flat at the top
||
||
||
|| <--12" or more, as needed double layer, water runs out the bottom..

The tube I used was for a giant tractor tire, so the top of the tube was folded flat and I cut it straight down to what would be the bottom rim, flat area of the inner tube.
I cut the bottom, so the flaps are separate and open facing down.

Then I drilled out the mud flap and drilled through the double layer of inner tube, and folding over the electrical assembly, effectively hiding and protecting the electrical circuitry from a direct overhead and front on splash and covering any flat surfaces with a double layer of good quality flexible rubber.

Any water projected up underneath falls down and out. All the circuits are protected with fuses, especially where they meet the buss-bar and have high voltage. Air can circulate through and dry everything off easy.


Yes, that is two #4 gauge battery jumper cable wires, stripped, shrink wrapped three times and hammer crimped into a #2 copper terminal on the left lug...
It is the main feed from the battery to the Buss. Big shrink rules. Buy some...


This gets small bolts nuts and washers and mounts to the section of mud flap.
See how it has holes above and below the covers? This style allows to you break away the lower cut outs, and wires come up from underneath. It's called a drip.

Mine does not have the plastic covers. You can use the covers or eliminate them with my design. You'll see later, when using the fuses I selected for the big battery wires, why the covers just get in the way...

The buss I used is rated for 600A and it came from SkyCraft, in Orlando... it came with 4 smaller screws for crimp on circle lugs. They are mounted on the outer edges of a much thicker aluminum buss block, than the one pictured, but this one will work too, with some mods... or by adding the smaller screw block in addition to this one, on your mud flap...

(Not shown.) for 10-16ga wires, to attach.
Main power feed to the battery and minor circuits 3/8" lugs. This setup, will feed dual batteries, your charging controller and your winch power feed, nicely.
I used one of the 23/8" lugs to make a home run to another power block on the driver's side rear fender wall. It has relays and 8ga power feed so the rear blazer window runs off relays with fat power to the fuel pump and rear window.
The old window power home run wires now run low voltage and only activate the relays on pin 35. All my relays, use fly back protection, with resistors and Zenor diodes soldered in... But that is another thread...

Used marine grade ice cube fuses on 2 ga and 4 ga battery wires to power the buss and smaller in line wired fuses with water protective fuses spliced everywhere else.

These hang from the buss bar.
They sell a similar unit with 2 cube fuses on it too.

The inner tube drapes over everything and hangs/bolts behind and down behind the mud flap. The mud flap does not contact the firewall.

The bolts to the buss bar do not touch the fire wall, because when they penetrate the mud flap, they are shielded from the wall.. by the inner tube.
Wrap around protection, folded over the top and Isolated.

In the past year, driving in tough weather, my fuses have not blown once,
...however there was more work to be done to prevent splashing...
If you've read this far, keep reading...

My advice for your install:

Remove your metal plate from under your distribution block and find an old chunk of mud flap and mount the entire system virtical, with a rubber or plastic open bottom shield of some sort, similar to above. Your metal plate can be used to make a flat surface where the hole behind your buss exists. Screw the plate nicely over the hole and use a grommet for your wires. You can access it later with screws.

The water will run down, if any gets up there, momentarily from your buss bar, with my design. You can silicone all the connectors under the clear plastic connector housings, as well, if you want it sealed. However, you may not need to, and it would make it harder to repair or rewire, with silicone all over the crimps...
It you are mudding and swamping, then by all means, silicone away.

The design is isolated, so the water cannot short to metal, because everything is double insulated... Triple in some instances...

How about the solder connections issue mentioned previously?...:
Silicone caulk was designed for aerospace connections to prevent moisture from building up in a space capsule.
When breathing in space, hot exhaled breath would condensate and short out the sensitive electronics.

Moisture behind the command module control panels, condensates on the freezing cold circuit boards, because the space capsule was in sub zero space. No air circulation or heated panels installed, to dry it off. They had never done this stuff before and stuff got messed up bad...

The aluminum can was frosty. Great film about when that exact problem caused a few issues getting a good guy home, if I recall..

The same thing will occur if you try to seal up your buss bar too tight, in your project.

You can cover the case with anything to hide the inner tube. Aluminum box, or plastic cover... Metal Cover can be in close proximity, so long as the inner tube is not perforated through both layers. Make it safe, then box it in for pretty.

Splash protection matters:
If you take old inner tube from the same tubes you found at the tire shop, and zip tie 36" lengths to the holes under your wheel wells, you can prevent a great deal of water from splashing into your engine bay. Saves the headers and exhaust manifolds from warping too. Cold water on your heads can't be good...

Try to hit up a tire shop for those big, 12" wide innter tubes, after they rip them out of a tractor with 5-1/2' tires. They just throw them away anyways, but they make great wheel well splash guards. Notch for your shocks and brake lines accordingly.

Be prepared to change it a few times, until yours look cool, straight, flush, cut correctly...

Nothing is really water proof. If there's air space, there's moisture in the box, period. Water Resistance is all we can achieve, without a vacuum, or a layer of silicone caulk.

The screws on top of my mud flap, going into the firewall, could use a gob of silicon on each of them, to make it bullet proof.

Just make certain you leave enough wire for every connection to have this:




You can get fussy and make it really nice. Crimp terminals from McMaster Carr or 3M work great.

These are for the die hard solder guys, so we don't get anyone's feathers wrinkled... Links:
McMaster Carr Solder Lined Heat Shrink Terminals
McMaster.com has good selection of heavy duty heat rated CRIMP terminals, without solder too. I try to avoid anything with thick hard plastic on the lugs.
A bag of HF shrink is cheap, just try to remember to put it on the wires before you crimp... and double or triple shrink where it might bend or become rubbed.

These are my go to:
3M Heat Shrink Ring Terminals


They are much heavier duty than the cheap crimps from overseas...

By good crimpers, like these LINK:
Ideal Terminal Lug Crimpers

I used these ^^^ same crimpers to make over 5000 crimps, per install, in several Casino and Hard Rock Corporate distributed audio/video system with zero defect... Anybody showed up with anything else, the one's they brought, got the trash bin, period.

If you select carefully at HF, you may find one in 250 similar crimpers, which might line up OK... Sometimes every one on the shelf is worthless.. or the handles won't move right...

For $10 bucks more the Ideal works. USA USA USA

I cannot stress enough the value of a main power disconnect switch, rated for 250-300 amps, between the battery GROUND and the BUSS_BAR.

Wrenching anywhere around my buss bar can be dangerous, if you accidentally lift a wrench up under the flap. A box covering it, would help.

Having the ability to shut off THE GROUND WIRE from every cicuit on the truck is invaluable... ecm reset, testing circuitry, theft protection... Mount it under the hood and use it often, is my program. Buy the best quality switch you can afford, without the plastic handles... they brake and fall out.

Be great to see what you do to protect your system.
I have not built a box for mine, because it doesn't matter to me.
The sides of the inner tube could have been laced up to make the flap permanent, but then would not have been able to access it when a fuse goes (or to take these pictures).

Hope this was helpful to somebody...

Wow thanks Ranchwelder, I did not expect such a reply! I will certainly revisit this thread when it's time to move that fusebox. You're right I could use some drip loops in there too.

It's just a 2WD street truck though, but the way my luck works, water and gunk will find it's way in there eventually. So the splash guard might be the way to go for now. Not sure about condensation though. Maybe mask everything off really well, and hit only the necessary areas with some spray paint. So only on the rings and screws and the metal they contact. Not even the plastic part covering up the crimp.

As for solder, I have the same experience. It likes to crack and corrode. That's one of the reasons I decided to rewire the headlights and the power windows, because previous repairs broke again. Might be the best of both worlds to crimp stuff on, then dab a little solder on the exposed part near the ring. The part where the wire barely sticks out of the crimp, next to where the ring is.

My suggestion was gonna be spray paint as well.
Though Once you get everything hooked up to it, you reasonably shouldn’t need to disturb it much if at all.
If that’s the case I like the liquid electrical tape idea.
Dielectric will protect it as well. Maybe less messy, use Fluid film instead of dielectric grease?

Other suggestion, although you have everything wired up nicely, these little fuse boxes from Blue Seas are fairly well protected. It is still open on the ends where each load wire come out though.

Our truck, the electrical system is in very good condition but I don’t like tempting fate and adding “stuff” to it. So I put this in for all aftermarket accessories present and future. These boxes are only $35 iirc. You could make one constant lower and one triggered on with ignition via relay.
That would be slick.

Soldering and crimping is not necessary, from my experience.

Tens of thousands of crimps in huge audio systems where the crimps are right at the loud speakers and huge sub woofers. Can you imagine if we were wrong and we had to remove every gambling table and hundreds of slot machines, every time a speaker zone went out? Picture the Casino owners face, after the fourth or fifth time we had a call back... no guessing here.

My job included wiring, repairing and flying the rig for World Tour Stadium lighting, audio and video systems for the largest audio, lighting fly rigs ever built.
...Rewire chain hoists and bench test them for overhead rigging. Thousands.

Dip the stripped wire into dielectric grease, the gray tube at the parts store, and crimp with added heat shrink layers. it stiffens the wire at the metal crimp like adding reinforcement. The plastic crimps you selected are for indoor use, like wiring an audio system or motion control in automation, where there's little to no vibration and no need for shrink.

Copper turns green with age from corrosion. Wherever the copper meets the acid for soldering, it creates a galvanic reaction. It is brittle exactly where the solder meets the copper. The copper will have micro pores from the acidic reaction of the flux. All solder uses flux to flow and to open the poors, or it drips off the copper. If you solder, you weaken the metal, right behind the crimp. There is where it can break, eventually in any automotive situation.

The tiny strand copper wires we get these days are worse than what was installed sub sized 16 gauge from GM.


Condensation cannot be avoided. You can however, isolate your power feeds and shrink and lube, so it cannot cause any problems. Ask any Navy electrician, especially a sub tech... it's a no win game really.

All the Casino's mentioned above were Marine Certified and inspected ships.
Several of them on the River.

Your rig looks very clean Grit dog. Same exact spot, with A/C still working.
Any 2WD would benefit from your install with room to grow. Nice fat battery feed...

The second wire from the left in my picture, is the wire from my alternator.
4 Gauge. All my grounds are 4 gauge with star washers, sanded and sealed with dielectric.

Air flow is key to heat and moisture. The more you seal it, the more it holds it.

Them headers are cool peaking out there in the center...
What's the lil' box in the middle with purple wires do?

Good tip on the drip loop,I forgot all about the importance of them.

Go on Amazon and search for "electronic hobby box".

GREAT thread and info. Sticky level stuff.

You have enough room on all sides to slip a bigger box over the whole works and seal it at the firewall? Here is what I did for a few relays.

Yeah I wanted to use one of those flat oem fuse boxes from the auto salvage yard, but they're really not made to be worked on easily like the aftermarket stuff is.

I have the exact same relay/fuse box and they are pretty weather proof. if you are worried about the attached terminal blocks you can just apply dielectric grease as others suggested but you will need to inspect regularly as some of it will dry out with high temps.