NASA Electrical Connection Standards

[Jason2tpa]

For those interested in how to crimp, splice, connect, strip, etc. electrical wiring the NASA way, follow the link below. I figured since they sent folks to the moon in a space shuttle with a million miles of wiring they probably know a thing or two about wiring methods.

https://nepp.nasa.gov/files/27631/NSTD87394A.pdf

[panasonic]

Link don't work Jason. I would like to see that PDF.

[Jason2tpa]

Link don't work Jason. I would like to see that PDF.

I clicked on the link I provided and it worked. The pdf file is too big to upload directly on the forum. Try it again. If it doesn't work for you, try this weblink: https://nepp.nasa.gov/index.cfm/5544

On that page are numerous standards to download, including the one I posted (right column).

This link directs to a pictorial interactive reference for every kind of electrical connection: https://workmanship.nasa.gov/lib/ins.../frameset.html

[panasonic]

I was looking at it on my phone..Works on my computer....thanks

[ausnoelm]

I don't think they have much of a salt water corrosion issue in space?

[Jason2tpa]

I don't think they have much of a salt water corrosion issue in space?

saltwater, freshwater, no water....the methods used to join wires remain consistent. Show a method that prevents saltwater from corroding anything over time and you'll be shown a nobel prize.

[rodbolt17]

when t comes to boat wiring I am more concerned about the USCG regulations over NASA's regs.
two separate missions.

[boscoe99]

What USCG regulations?

[rodbolt17]

the various ones about the connection must be mechanically connected(swaged,crimped etc) you can solder it after mechanically connecting it but not solder only.

[Jason2tpa]

Speaking of the best method for joining 2 wires together....while I wait for my new fuel tank to be fabricated I've taken the opportunity to reconfigure/replace all the electrical wiring under my console.

Below is a picture of my starboard deck with the red arrow pointing to the removable panel. 40 years ago, instead of the engines wiring being below deck, AQ assembled the 17ft model with this panel. Under the panel is a tray. All engine to console cables/wiring lays in this tray. The accessibility is convenient. The down side is everything in this tray gets wet. And wet is an understatement...standing water in this tray is common.

The engines 12v power cables do not run the length of the tray. Either 2 or 4 gauge cable is spliced in, both + and -. The connections are taped up pretty good. I have not unraveled to look at the connections because I never had a reason to look.

Long winded backstory, sorry. Question is, since the connections have had countless exposures to saltwater, should I cut out the connection and make new ones despite no evidence of voltage drop?

If so, what connection method is recommended for such a large gauge? Butt connect...how would you crimp such large gauge? And other than heat shrinking the connection, is there anything I can do to provide at least some water resistance to the connection?

[panasonic]

How about a few more pictures with the panel removed so we can see of what you speak....

Pictures worth a thousand words.

[99yam40]

they make crimpers for all sizes of electrical connectors.
If you can buy the connector you can buy a crimper to do it with.
might be a little expensive to do a couple of connections tho.
probably cheaper to just not make connection in there

they make a liquid tape you brush on. I forget the name of it. but you need something over it also

How is the water getting in there?
try and seal it better.
find a way to elevate the wires so they do not lay in the water.
Some wire insulation does not like water for long periods of time

[Jason2tpa]

Unwrapped the electrical tape and this is what I found. 1st picture is before I cleaned it up with electrical spray, 2nd is after:








I don't think I'll ignore this connection even though I have not experience a voltage drop. Because i will eventually with the way this looks. Not sure what type of device is being used to join the wires. I could see on the negative side 2 screws in that metal looking block. Either way, I'll cut it out, both + and -. I'd prefer using annealed tinned copper butt connectors, heat wrap, then either use liquid electrical tape or this self-fusing silicone tape, pictured below.

How is the water getting in there? try and seal it better. find a way to elevate the wires so they do not lay in the water.
Some wire insulation does not like water for long periods of time

It's difficult to describe here in words....the picture I posted in my first thread shows the removable deck panel that covers the tray. And you can kinda see with the 2 pictures above, on far left of pictures, how the hoses/wires lay in a white tray and the blue deck is elevated. The panel lays on top of the flange.

At the stern, all of the engines hoses/wires come out of engine and duck under this panel and lay in a tray, running up to console. At the transom, there is a beam-to-beam channel about 2in wide, just below the scuppers. This channel is below the deck level. So let's say I'm out netting bait and after I wash down deck I'll open the plugged scuppers and throttle up to let water drain out. So when I'm washing deck down water flows aft then "channels" starboard into tray and forward towards console. Same thing happens when I wash down boat after a day on the water at the boat ramp. It's impossible to keep the tray dry. With that said, every person I know who has restored AS 17"s that have this tray do not include it when re-decking.

No point in trying to elevate the hoses/wires off the tray, water will still get to them. I think the idea is to limit the water from getting into the starboard tray. I'll hunt around and talk to some of my AS contacts to see what they say.

40 years ago AS did not install bilge pumps in the 17ft model. The boat is self bailing and meant to be operated with the scuppers open.

[Jason2tpa]

Unwrapped the electrical tape and this is what I found. 1st picture is before I cleaned it up with electrical spray, 2nd is after:








I don't think I'll ignore this connection even though I have not experience a voltage drop. Because i will eventually with the way this looks. Not sure what type of device is being used to join the wires. I could see on the negative side 2 screws in that metal looking block. Either way, I'll cut it out, both + and -. I'd prefer using annealed tinned copper butt connectors, heat wrap, then either use liquid electrical tape or this self-fusing silicone tape, pictured below.

How is the water getting in there? try and seal it better. find a way to elevate the wires so they do not lay in the water.
Some wire insulation does not like water for long periods of time

It's difficult to describe here in words....the picture I posted in my first thread shows the removable deck panel that covers the tray. And you can kinda see with the 2 pictures above, on far left of pictures, how the hoses/wires lay in a white tray and the blue deck is elevated. The panel lays on top of the flange.

At the stern, all of the engines hoses/wires come out of engine and duck under this panel and lay in a tray, running up to console. At the transom, there is a beam-to-beam channel about 2in wide, just below the scuppers. This channel is below the deck level. So let's say I'm out netting bait and after I wash down deck I'll open the plugged scuppers and throttle up to let water drain out. So when I'm washing deck down water flows aft then "channels" starboard into tray and forward towards console. Same thing happens when I wash down boat after a day on the water at the boat ramp. It's impossible to keep the tray dry. With that said, every person I know who has restored AS 17"s that have this tray do not include it when re-decking.

No point in trying to elevate the hoses/wires off the tray, water will still get to them. I think the idea is to limit the water from getting into the starboard tray. I'll hunt around and talk to some of my AS contacts to see what they say.

40 years ago AS did not install bilge pumps in the 17ft model. The boat is self bailing and meant to be operated with the scuppers open.

[panasonic]

Well it looks like you got some more work to do. From looking at the pictures you probably have corrosion wicked up the cables from the splices. So hopefully you got enough slack to cut it back until you find good wire.

If it were mine I would use crimped butt conectors and solder after crimping. Then weather proof heat shrink over the joint.

Problem is the crimper required to do a decent job on big crimps like that. If you where home with the cable you could do a DIY with a vise, hammer and punch. Then solder to fill in any voids. But you need to do aboard your boat.

The heat shrink needs to be good quality with sealing adhesive inside it to make it truly waterproof. 3m makes very good heat shrink ( same stuff used on aircraft) and is not cheap. If you go to a electronic/electric supply store you can get it plenty cheaper than a marine store.

As for that self sealing silicone tape I would stay away from that. We call that triangle tape or USAF F4 tape. It has its purposes ( we tape up cannon plugs with it mostly) but in that area where your are working heat shrink with built-in adhesive would work best.