[HN Gopher] NASA Workmanship Guide for wire splicing
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NASA Workmanship Guide for wire splicing
Author : asimpleusecase
Score : 118 points
Date : 2024-02-02 12:10 UTC (10 hours ago)
(HTM) web link (workmanship.nasa.gov)
(TXT) w3m dump (workmanship.nasa.gov)
| crmrc114 wrote:
| Looks like the entire guide is here
| https://workmanship.nasa.gov/lib/insp/2%20books/frameset.htm...
|
| Pretty darn cool little site, will have to mirror it.
| cuSetanta wrote:
| Have used this site a lot over the years, really useful
| resource. I wish ESA was more willing to do this sort of
| guidance document rather than just the requirements.
| dotancohen wrote:
| NASA has some terrific workmanship videos as well. Here is the
| one on soldering techniques:
| https://www.youtube.com/watch?v=_RXugDd0xik
| haaz wrote:
| Great guide, especially for beginners/laymen.
| gumby wrote:
| I consider these advanced splices. Someone fixing a power cord
| in their house need not go to such extremes.
| gottorf wrote:
| Just a reminder to all homeowners that the other extreme is
| also bad; you can't just wire-tape two Romex cables together
| in an attic and call it a day!
| dylan604 wrote:
| I wish someone had told the person that did nearly this
| very thing to the low voltage control cable to my external
| AC compressor. At least in the attic it would not be
| exposed to weather and UV. <facepalmEmoji>
| onetimeuse92304 wrote:
| I always splice wires considering these good practices,
| regardless of what application. I just like doing things
| correctly and reliably.
|
| I also have a little bit of a fetish. I really enjoy it when
| other people do their work correctly and do those small
| things that show their prowess. And I like to to think
| somebody someday sees what I did and will enjoy it the same.
|
| That's why, when I sail, I always have all my lines neatly
| tied and organised. And use proper knots for their
| applications. And look at other yachts when docked to see if
| their owners know what they are doing or not.
| semi-extrinsic wrote:
| Do you knoll when building Lego?
| onetimeuse92304 wrote:
| These days I leave Lego for my kids.
| gumby wrote:
| Have considered those standards in some safety critical, high
| vibration applications. NASA aren't kidding. It was eye opening
| to me to consider crimps superior to soldering in terms _other_
| than convenience.
|
| We never got out of the prototyping stage but it was clear that
| we wouldn't use this approach for the parts of the system that
| weren't vibrating. Of course if you're building a space- or
| aircraft it's worth doing this pretty much everywhere.
| chkaloon wrote:
| I got trained in NASA soldering standards in the early 80s.
| Worked as a tech in college helping build test harnesses for an
| X-Ray telescope that was to fly on Challenger. Got delayed after
| the accident, but I think it eventually flew 20 years later.
|
| They were very serious about this stuff, for obvious reasons. No
| rework possible in space.
|
| I still use those skills on my home DIY hobbies.
| dylan604 wrote:
| > No rework possible in space.
|
| I suddenly started imagining someone trying to strip some wire,
| twist the strands together, hold a soldering iron and the
| solder and the wires all while essentially having Mickey Mouse
| fingers from being in a space suit. If something ever deserved
| the No User Serviceable Parts Inside sticker...
| calamari4065 wrote:
| I really hope someone stuck a "no user serviceable parts" or
| "warranty void if removed" sticker on JWST
| rickydroll wrote:
| That is why they made Wago lever nuts
| dylan604 wrote:
| Being unfamiliar with this, I had to look it up[0]. While
| these look interesting, I can't imagine where I'd use them.
| They are _HUGE_. Like bigger than that even. I can 't
| imagine unbolting the side panels of a satellite in space,
| being able to use one of these, and then it being able to
| fit back into the original position.
|
| [0] https://www.wago.com/us/discover-wire-and-splicing-
| connector...
| verisimilitude wrote:
| They're _excellent_ for wiring devices into junction
| boxes in construction; particularly when connecting the
| higher gauge luminaire wires of an overhead light to
| romex. For some reason they're polarizing among
| electricians in the US (they carry all necessary listings
| for use in the US...). By contrast, they're widely
| accepted and used elsewhere.
| quickthrowman wrote:
| > For some reason they're polarizing among electricians
| in the US
|
| They're 8x more expensive and take longer to install than
| a wire nut, and they take up more space inside the device
| box. They're also difficult to unterminate without
| damaging the lever nut or conductor.
|
| It's not hard to splice #14 solid to #18 stranded with a
| wire nut, you just extend the smaller wire a bit beyond
| the end of the larger wire and twist.
|
| I'd recommend wago lever nuts to homeowners doing their
| own electrical work because homeowners are terrible at
| electrical work and the less chances for electrical
| fires, the better.
|
| I'm a commercial electrical project manager in the US.
| dylan604 wrote:
| > they're polarizing among electricians in the US
|
| sounds like it needs a ground! /s
|
| but seriously, what kind of junction boxes are used
| outside the US that these would fit?
|
| as far as connecting a larger device wire to a smaller
| mains line seems odd to me. granted, i'm not an
| electrician, but it is pretty much opposite of all of my
| experiences with wiring commercial lighting and home
| lighting
| mikeyouse wrote:
| I use them almost exclusively in my home wiring - they're
| _so_ much more user friendly compared to wire nuts. They
| are not large at all - I find wiring that these take a
| lot less space in tight boxes than a wire nut since they
| 're flat and you can push them to the back more easily:
|
| https://imgur.com/a/tGTUJd9
|
| They make stab Wagos as well which I don't recommend, but
| the lever ones are great. You can work 'hot' if you need
| to replace a switch or anything (don't work hot blah blah
| blah). Much of my existing wiring is crappy 50s era
| copper and in some areas, aluminum -- so to add GFCIs
| where useful, I use either the levers to join copper of
| shitty provenance or the ALCU junction connectors and a
| bit of the paste.
| wrs wrote:
| This 1958 NASA soldering training video still holds up pretty
| well (aside from the sociological aspects!).
|
| https://youtu.be/_RXugDd0xik?si=Z9ToN_tMz0m6lHu3
| bumby wrote:
| > _They were very serious about this stuff, for obvious
| reasons. No rework possible in space._
|
| There are other reasons that may be less apparent, like the
| fact that materials can have weird properties in space. One
| example is solder "whiskering"[1]. I believe NASA requires
| techs to be certified to the IPC-JSTD [2].
|
| [1] https://nepp.nasa.gov/whisker/
|
| [2] https://www.ipc.org/ipc-certifications
| Clamchop wrote:
| Note that tin whiskers happen in air here on Earth, too. Not
| a thing that only happens under vacuum.
| instagib wrote:
| Whisker growth rates from 0.03 to 9 mm/yr have been reported.
|
| There are some elimination methods such as conformal coatings
| (very hazardous) and plating finishes (nickel/gold/palladium)
| that have been tested. I got certified by the IPC-J-STD-001H
| also soldering 201 surface mount components 0.6x0.3x0.25mm
| 0.05W handling.
| idlewords wrote:
| I want to compare this to the Boeing guide
| dylan604 wrote:
| When adjusting the bolts to the aircraft doors, adjust until
| finger tight
| jeffrallen wrote:
| ...if bolts are even present.
| dylan604 wrote:
| This hole left intentionally blank
| r2_pilot wrote:
| *unintentionally
| polishdude20 wrote:
| The characters "u" and "n" have been unintentionally left
| out.
| dylan604 wrote:
| We hope? With the info that has come to light about the
| processes and decision making within Boeing, I would not
| be surprised if some bean counter calculated that
| removing 0.5% of all bolts would reduce weight enough to
| improve fuel consumption. Of course this is totally made
| up conjecture on my part, but I would not be surprised by
| it one bit.
| zokier wrote:
| As I commented in the other thread where this comes from, not
| really current anymore.
|
| > That is very old reference, and afaik not used at NASA anymore.
| More current ref would be https://s3vi.ndc.nasa.gov/ssri-
| kb/static/resources/nasa-std-... but also note that NASA has been
| moving away from having their own standards and instead adopting
| industry standards: https://nepp.nasa.gov/index.cfm/26139
|
| https://news.ycombinator.com/item?id=39227420
| beefnugs wrote:
| I swear i recently was looking up torque recommendations per
| thread size into aluminum and NASA seemed like the only source
| to show up
| quakeguy wrote:
| Your first link doesnt work fyi.
| zokier wrote:
| Oh right, it got mangled from copying the comment over. Here
| it is full: https://s3vi.ndc.nasa.gov/ssri-
| kb/static/resources/nasa-std-...
| wolverine876 wrote:
| From the second link:
|
| _The NASA Workmanship Standards Program has been working to
| adopt IPC /WHMA-A-620xS since 2008. The goal is to allow the
| use of IPC/WHMA-A-620B-S, Space Applications Electronic
| Hardware Addendum to IPC/WHMA-A-620B as an alternative to NASA-
| STD-8739.4, Crimping, Interconnecting Cables, Harnesses, and
| Wiring. This change facilitates a move by suppliers towards the
| industry voluntary consensus standard but does not force those
| suppliers who cannot accommodate the current IPC/WHMA-A-620B
| training options to do so._
|
| Notice that the statement is undated but says they've been
| working on it "since 2008"; possibly that statement is old too.
|
| I see that NASA is turning to space industry standards, not
| general electrical standards (e.g., for a commercial building).
| But I wonder why do it at all? I assumed NASA's internal
| standards met their quality and performance needs, but maybe it
| was just that there were no industry standards when NASA
| developed theirs?
| zokier wrote:
| I assume some of these standards might have their roots in
| Apollo days or something, and definitely there wouldn't have
| been many options back then. But why change now? The give
| clear explanation:
|
| > In 1998, NASA established by internal mandate, the need for
| all NASA standards users and custodians, to comply with the
| 1995 Office of Management and Budget (OMB) Circular A-119 on
| Federal Participation in the Development and Use of Voluntary
| Consensus Standards and in Conformity Assessment Activities.
| This directive compels the NASA Workmanship Project to
| actively identify, enhance and adopt industry standards which
| can be used in lieu of the NASA-STD-8739 series documents.
|
| Of course you might ask why that OMB was made, but tbh it
| just makes lot of sense imho, maintaining own set of
| standards is not cheap especially with all indirect effects
| that it implies
| spacecadet wrote:
| Ah yes, this has graced these halls many times. I use the SOLDER
| SLEEVE SPLICE INLINE as often as I can.
| whoswho wrote:
| Pair the NASA documents with PACE soldering/rework videos to have
| a successful outcome each time, all the time.
| p1mrx wrote:
| For practical purposes, the lineman splice is probably the most
| useful one to learn. It's only moderately more difficult than the
| obvious "pair up and twist" approach, but the wires remain
| collinear.
| kbr2000 wrote:
| There's another guide [0] for wire wrap technique (solderless,
| cold welded connections to square posts [1]). Used extensively in
| telephony switching/patching in the past, as well as digital
| circuit construction like computers. Quite nice for prototyping,
| although qualitative sockets/posts can be hard to acquire at a
| reasonable price nowadays.
|
| [0]
| https://workmanship.nasa.gov/lib/insp/2%20books/links/sectio...
| [1] https://en.wikipedia.org/wiki/Wire_wrap
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