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Firewall passthrough for battery cable

B

bob888

Well Known Member
I would like to know what others have done or thought of doing about the Van's standard plastic grommet through the firewall for the battery cable. It is in a tight spot and probably can't put firesleeve or a steel cover there. Perhaps just some red RTV? Major change in cable routing? Leave as is? Input appreciated.
 
I purchased a marine bulkhead pass-through. It's bulky and a bit heavy but I didn't feel comfortable with the snap-bushing. Besides, I like terminating the cable at the bulkhead rather than having it physically pass through the firewall where it could possibly chafe and ground or be severed in an accident and spark a fire. Probably overkill but I felt it was the right way to do it.
 
connector

Yeah, I ordered a couple of marine pass throughs but they were really bulky. Then I found the VTE product. Compact, easy to install, and carries 550 amps...oh, and they are comparatively inexpensive!
 
Oh, still have the marine connectors, if you decide to go that way...I will make you a deal!

These are the 400 A version, which has been discontinued.

https://www.bluesea.com/products/old/2206

I have 2 red ones, sorry Black was out of stock everywhere but my intent was to spray one of them Black.

If you want them, send me a message!
 
Pass thrus

Not an RV builder but I use flanged stainless tubing(035 tubing .063 flange). I made my own but they are available from the company that makes the all stainless cabin heat boxes. Flange is tig welded and four 6-32 stainless screws with stainless lock nuts hold it in place. Fire sleeve around the cables, sealed with the 2000 degree "goop" from Lowes.
I made four of these, also use stainless bulkhead fittings for fuel line, brake lines etc.
 
I used a -8 AN steel bulkhead fitting and with a lathe bored out large enough for slip fit of the cable. Also shortened the fitting to overall about 1.2" long and put decent-size lead-in/lead-out chamfers to keep from chafing the cable. After 8 years in use, the cable looks perfect.

Just remember to push the cable through the bulkhead fitting before crimping on the last end...
 
For those who have used the VTE bushings, did you buy the Greenlee punch? If no, how did you make the 1.375x1.125 size holes?
 
Punch

Sent you a PM.

Couldn't justify $350= for the punch for only two holes so cut them manually.

Took less than 1 hour for both holes...
 
kcpilot81 said:
For those who have used the VTE bushings, did you buy the Greenlee punch? If no, how did you make the 1.375x1.125 size holes?
Click to expand...

I just looked at these pass-throughs, pretty slick. I see no reason why you can't mount them in a round 1.375" hole. A uni-bit or hole saw can be used for drilling the hole. You lose the anti-rotation feature with the round hole but that shouldn't be a problem during assembly if you can immobilize one end of the pass-through.
 
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The VTE pass through, rated to over 500 volts is good, but at what temperature does the plastic terminals begin to fail. if there was an engine fire and the plastic melts, then you may have a main power line short right at the firewall, that could cause fire and smoke to enter the cabin.
 
Risk Management

Although the ONLY way to be truly safe is to NOT fly the airplane, it is a valid point...one that I considered for quite awhile.

Then I realized that Van himself recommended drilling a hole in the firewall, inserting a plastic bushing, and running a #2 AWG cable through the plastic bushing. I don't think that the insulation on that wire is going to hold up any better...

That being said, I am mitigating the issue by making a heat shield from 018 stainless that will help to shield the pass through...
 
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