What gauge wire and solid or stranded from altimeter to terminal blocks?

[mpitfield]

I am using a Stratologger and cannot find a recommendation in the user manual on what gauge and type of wire, solid or stranded to use to feed the terminal blocks for the pyros. My instinct tells me stranded will be better for vibrations and to tin the end for better continuity, and that 22 gauge would be optimal.

What advice can you experienced fliers provide?

 

[Vaportrail]

Sounds good to me. I use 24ga stranded/tinned. I think the important aspect is stranded/tinned.


Mark

 

[jderimig]

I can't resist. Tinning stranded wire with a terminal block is not good practice. But it won't doom your flight. Controversial subject though. (search the forums).

See this reference from Phoenix connectors Pretreatment Section.

 

[Coop]

So far, my favorite is repurposed CAT 5 cable. I came across a large supply in a dumpster behind a strip mall--one of the storefronts was being re-worked to make some crappy burrito place, and they had oodles of the stuff thrown in there with the drop ceiling framing. I took about fifty feet out of there and it's worked well.

Oh, and it's solid wire pairs. Pretty sure it's 22ga.


Later!

--Coop

 

[Cyril's Scribe]

The best material that I have found so far is the 24 gauge two-conductor "speaker" wire. It comes in a large reel and includes two wires in one "package", this helps to minimize clutter inside of the av-bay. That and it is fairly inexpensive.

 

[Rocketjunkie]

E-matches wired directly to the altimeter. New wires every flight. (They're 22 gage solid.)

 

[Airobert]

Those little screw in clamp connectors confuse me. I put the wire in, tighten the screw, give the wire a test tug and its fine. Then I do the same for the other wires. When I come back and do a final tug test it seems that half of the wires fall right out.
Or sometimes I put the wire in, tighten the screw and Viola' the wire isn't held at all.
They should be dirt simple, but somehow they don't work well for me.
I am sure some failures are due to using two wires in the same terminal, but not always.

Stranded wire should be better for vibration, but the reality is you won't fly the rocket enough to get vibration failures in solid wire.

If you are using more than one wire per terminal the wires should be stranded and the same gauge size so you don't just clamp the big wire and have the other wires loose.

 

[Feckless Counsel]

mpitfield,

AWG22 with 7/32 stranding. Resistance is 15 milliohm per foot. Don't tin exposed wire. Do use a proper wire stripper. Strain relieve the wire periodically and especially near the altimeter. If you solder to switches strain relieve across the connection using shrink tubing.

Feckless

 

[Adrian A]

24 or 26 gauge wire is what I prefer. Electrically, you can go even thinner if you want, as long as it's not 10s of feet. I used to use 26 gauge solid core wire, but I had one break under the insulation; an invisible failure.

 

[cavecentral]

I used lots of repurposed ematch leads on older builds. This is solid 22 AWG. Not ideal. Cat 5 is solid or stranded 24AWG. I have both. Never tinned the ends of stranded because I figured that made it effectively solid at the stress point.

I'd like 22 AWG stranded for larger builds 24AWG stranded for smaller. Stranded is more flexible, and less brittle for continued movement. I like CAT 5 because the insulation is reasonably thin vs. speaker wire.

In the past I tried 20 AWG solid 'bell wire' - that stuff is terrible. Too heavy and doesn't bend easily. Nothing much smaller that 24AWG, you may have to double it over to get enough material for the terminal blocks on the altimeter to bite. Some terminal blocks just have screws, some have a screw push a plate down. The screw only push small wires to the side instead of clamping, so double check the connections.

 

[cavecentral]

Those little screw in clamp connectors confuse me. I put the wire in, tighten the screw, give the wire a test tug and its fine. Then I do the same for the other wires. When I come back and do a final tug test it seems that half of the wires fall right out.
Or sometimes I put the wire in, tighten the screw and Viola' the wire isn't held at all.
They should be dirt simple, but somehow they don't work well for me.
I am sure some failures are due to using two wires in the same terminal, but not always.

Stranded wire should be better for vibration, but the reality is you won't fly the rocket enough to get vibration failures in solid wire.

If you are using more than one wire per terminal the wires should be stranded and the same gauge size so you don't just clamp the big wire and have the other wires loose.

I've over tightened some solid, crushing the wire flat. These broke easily as I effectively cut it with the screw.

 

[billspad]

I can't resist. Tinning stranded wire with a terminal block is not good practice. But it won't doom your flight. Controversial subject though. (search the forums).

See this reference from Phoenix connectors Pretreatment Section.

I recall seeing a picture of one of your altimeters that I think you posted that had some kind of termination at the end of the wires where they go into the terminal block. It looked like they might be prototype board jumper wires. Is that what they are?

 

[jderimig]

I recall seeing a picture of one of your altimeters that I think you posted that had some kind of termination at the end of the wires where they go into the terminal block. It looked like they might be prototype board jumper wires. Is that what they are?

These are wire ferrules. Makes the terminal block connection with stranded wire much more reliable and solid.
https://ferrulesdirect.com/electrical/WIRE_FERRULES.htm

 

[billspad]

These are wire ferrules. Makes the terminal block connection with stranded wire much more reliable and solid.
https://ferrulesdirect.com/electrical/WIRE_FERRULES.htm

Will the crimping tool for common crimp connectors work on these or do I need the expensive crimping tool?

 

[Greg Young]

I followed John's advice, use the ferrules, and went with the expensive crimping tool, a one time investment.
I don't want to risk less than solid crimping, given the costs of what I am protecting.

 

[jderimig]

Will the crimping tool for common crimp connectors work on these or do I need the expensive crimping tool?

A fine Molex type crimp tool will work. You'll know if you got a good crimp (tug test). But $60 for a crimp tool isn't too bad.

 

[billspad]

A fine Molex type crimp tool will work. You'll know if you got a good crimp (tug test). But $60 for a crimp tool isn't too bad.

So it looks like you're saying the $25 tool isn't going to do it. I should have gotten a Molex tool years ago. I solder them.

 

[jderimig]

So it looks like you're saying the $25 tool isn't going to do it. I should have gotten a Molex tool years ago. I solder them.

I have used the cheap crimp tool with no problems. Once an awhile it will fail the tug test and I would have to do it again. But the ferrules are cheap.