Insulated Bus Bars

[rwanttaja]

I'm getting ready to do some major electrical re-work on my Fly Baby. One thing I want to do is add a pair of bus bars to give a common point for power (a pair, since the Fly Baby has a wood structure and thus there's no structural ground).

All of the bus bars I've looked at are just "bare." For the plus side at least, I'd like it to be behind an insulated cover in case a bit of metal or a wire somewhere comes loose and flops onto the bar. Could build a bit of a wood box, but I'm hoping someone someone knows of a commercial bar that includes a cover or other way to insulate the bar.

Ron Wanttaja

[tom_walter]

Most commercial bus bars are probably to heavy.
Mc-Master Carr with 2 x 10 screws is rated for 100 Amp.
9290T13 (http://www.mcmaster.com/#) & cover 9290T26 (http://www.mcmaster.com/#) will run about $42.00

My recommendation, for size and weight, would be a ATC fuseblock with
ground connections.
http://order.waytekwire.com/productdetail2/M50/46063/ATO%20/%20ATC%20FUSE%20BLOCK%2012%20GANG/
ITEM # 46063 $15.00

ITEM # 46060 $11.00 - Six fuses.

You can also find the ATC fuses with a build in LED. Fuse blows, circuit powered up, you'll see the LED telling you blown fuse.

Tom
Bearhawk builder

[Bill Ladd]

This might work: http://www.erico.com/products/ERITECHIntersystemBondingTermination.asp

It's an exterior bonding termination for residential electrical services. Can be easily found at the big-box stores or any electrical supply.


'bout twelve bucks.

[Kyle Boatright]

Have you considered a fuse block?

[Tom Downey]

Make it....... from a copper bar stock, some brass flat head screws, solder the screws to the bar and run a heavy wire to the battery - side

[rwanttaja]

Make it....... from a copper bar stock, some brass flat head screws, solder the screws to the bar and run a heavy wire to the battery - sideI know how to make a bus bar, what I'm looking for is one that is insulated. I once had a car with exposed power leads...too big of a bump, and sparks would fall from behind the dash. I want the convenience of a bus bar, but completely covered.Kyle's suggestion is interesting, I'll look into it.Ron Wanttaja

[Tom Downey]

The only way to get sparks from a buss bar is to have a loose connection,, don't have any.

is it mounted on a wood surface?

you could dip the whole thing in liquid electrician tape.

[rwanttaja]

The only way to get sparks from a buss bar is to have a loose connection,, don't have any.

is it mounted on a wood surface?

you could dip the whole thing in liquid electrician tape.

It's going to be installed in a wood airplane, but it'll be within a few inches of the (grounded) fuel tank. My personal preference is to not have any exposed electrical contacts. That way, there's no chance of throwing sparks from a screwdriver slip or from the zipper on a flight suit. A few years back, during maintenance under the cowl, the end of a piece of safety wire slipped under a rubber boot on the starter switch terminal and shorted the 12V to ground. I got a nice burn pulling it away.

"It shouldn't have had power on at that contact," you say? Certainly. But that's the way it was built. For some reason, the guy who built my airplane didn't use a master solenoid. In fact, in its original configuration, you had to remove the radios to reach the battery to disconnect it. I fixed that about ten years back.

So I've seem enough sparks and smoke over my ~16 years of ownership, and am reworking the electrical system as part of a general panel replanning effort. The original builder probably didn't expect some clod with a long piece of safety wire might make contact with those live posts (in fact, I KNOW he didn't, because he didn't even install rubber boots on them...I added some). He probably didn't expect that some wrench-turning idiot would remove the avionics stack, exposing the battery, then move some stainless steel floor plates and have one of them make contact with the + terminal on the battery. BTW, this is right under the fuel tank.

But, it happened.

Similarly, I figure I could leave bare bus bars and not have any problems during maintenance. But that doesn't mean a later owner will take the same care. So...I'd just as soon not leave them exposed. I'll probably leave the negative bus bar open, but I do want a cover on the positive bar.

Dipping the thing in liquid tape is an interesting thought. The only drawback I see is if I ever had to remove one of the wires or install an additional one....

Ron Wanttaja

[CraigCantwell]

Ron: Cut and drill the bar with any additional length you think you want. Dip the entire bar in one of the insulating plastic/rubber dips and let dry. Now use an X-acto and cut away the the dip only where you need to for connections. Trim to fit the breaker on the one side and just enough for the screw and washer on the other. If you end up needing some more positions, all you need to do is trim away the covering for the next breaker and install it.

[WLIU]

Sounds like you want a cover. Why not just make a quick form out of foam, drape some glass and epoxy over that, cure, trim, and screw into place? Light weight and high insulating value.

Best of luck,

Wes
N78PS

[turtle]

Ron: Cut and drill the bar with any additional length you think you want. Dip the entire bar in one of the insulating plastic/rubber dips and let dry. Now use an X-acto and cut away the the dip only where you need to for connections. Trim to fit the breaker on the one side and just enough for the screw and washer on the other. If you end up needing some more positions, all you need to do is trim away the covering for the next breaker and install it.
I really like this idea.

Or just wrap in electrical tape. It was good enough for a Piper open bus bar AD...

[TOMKJ9P]

Ron
After you have sized the bar for the ampacity required, lay it out for the distance between lugs you need, and drill and tap the holes. I would use a minimum of 10-32 tap size. Once the whole bar is drilled and tapped you can then slide the right size heat shrink tubing over the whole bus. After shrinking, the tapped holes will appear as slight depressions. Using a sharp pointed tool, poke a hole in each depression. Then
using one of the lugs as a template, and a 10-32 screw, lightly tighten the lug to the bus. With a "sharpy" draw an outline around each lug. Next, cut out the heat shrink material from under the lug area. The remaining insulation should remain in place and provide the insulation safety you are looking for.
Tom KJ9P

[jimwalker]

Many years ago on a company project, we used a material that I think was called strippable vinyl. We got it at a marine supply store and it is intended to provide corrosion protection for electrical connections. It is easy to cut and adhers only to itself so changes and maintenance are easy. It can be applied by brush, dip, pouring, etc. It is very similar if not the same as the tool dip. I suspect that safety wire will easily puncture it. Kapton tape is very good at resisting puncture and could be applied to the bar but not easily cover the connections. It seems like a box cover would need to be custom and when you need it the most is when it is removed for maintenance.

[Eric Page]

Another idea is to use a thermoplastic sheet (Kydex is the most popular and readily available) to form a cover to the shape you want. A block of wood shaped as a mold would work quite nicely. I've used Kydex to make sheaths and holsters and it's pretty easy to work with. You can get small sheets of it on Amazon. Heat it up in a toaster oven until it's pliable, then form it. Trim to size and drill as needed. There are several grades of Kydex, some of which are FAA approved for aircraft interiors.

For general info and spec sheets: http://www.kydex.com/

I built a mold press for my projects. If the part you need isn't bigger than about 2x8x10, I could press it for you.

[terry.mortimore]

Hi Ron: I used large shrink wrap to cover my exposed bus bar. I'm pleased with how it worked out.


Terry.

[rwanttaja]

Thanks for all the suggestions, folks. I found this at a marine supply store (http://www.boatersworld.com/product/MP63505631.htm?bct=%3Bciboat-care%3Bciboat-electrical%3Bcipanels-wiring%3Bciterminal-fuse-blocks):

http://a1672.g.akamai.net/7/1672/116/20120201/www.ritzcamera.com/graphics/products/m-31/large/MP63505631_bg.jpg
Just $17, and there's a version without the insulated cover (for the ground) for just $7. It's not perfect (looks like some of the power strip is still a bit exposed with the cover in place) but I can probably add an additional bit of insulation.

Ron Wanttaja