[HN Gopher] The lost art of lacing cable (2018)
___________________________________________________________________
The lost art of lacing cable (2018)
Author : voxadam
Score : 304 points
Date : 2023-03-07 13:33 UTC (9 hours ago)
(HTM) web link (www.thebroadcastbridge.com)
(TXT) w3m dump (www.thebroadcastbridge.com)
| tyingq wrote:
| The corrugated cable sleeves that you see under the hood of your
| car are certainly easier. I suppose it has the downside that it's
| usually opaque, so you can't see the cables inside, but there are
| ones made with braided material.
| djha-skin wrote:
| Discussed previously on this site:
| https://news.ycombinator.com/item?id=20582844
| jamincan wrote:
| The company I work for develops geophysics instruments and we
| lace the wire bundles in our equipment. The feedback I've heard
| is that it isn't great in terms of ergonomics for the technicians
| who do the lacing - repetitive strain injuries are a problem.
| Wistar wrote:
| In the large-scale video post-production facilities I worked in
| the 80s and early 90s, almost all the cables -- miles and miles
| -- were artfully laced with black linen flat lacing cord. One
| chief engineer in particular would sometimes loudly criticize
| other engineer's lacing work and tear it apart and re-lace it
| himself. Great engineer but not well-liked.
| tibbon wrote:
| This is really helpful to me right now. I'm finishing up a large
| home recording studio and I'm looking for better ways than Velcro
| and zip ties to help dress wiring
| brudgers wrote:
| I wonder how easy it is unlace cable when something breaks or
| gets replaced or new hardware gets added or a musician changes
| their mind or has an idea that requires a novel signal chain.
| bluGill wrote:
| Most studios are moving to digital. A ethernet stagebox
| (normally Dante, but there are other options) where each
| performer is, connect to your network. Just run an ethernet
| jack and power to various locations where you might want
| something and plug in what you want. You can get in-wall
| versions of the above to use in places where you will always
| have a lot of stuff connected.
|
| You still have the mic cables on the floor, but they are
| going to be there all the time and the ones that change most
| often.
| tibbon wrote:
| Everything is running to a large patchbay that helps with
| this, but your concern is entirely valid
| LeSaucy wrote:
| Any benefits of this over velcro straps?
| VLM wrote:
| Its kind of assumed by building inspectors that 'new' (post
| 1970s) lacing is fire retardant. Plenum rated velcro is
| available but unfortunately both costs more and looks
| absolutely identical to the flammable stuff, so building
| inspectors sometimes look askance at it.
| throwanem wrote:
| It's a hell of a lot easier to pull through a conduit.
| bichiliad wrote:
| I had to run some long speaker cable around my living room, and
| this guide really made it so much easier to keep things neat. I'm
| glad to see it reposted again.
| jdeibele wrote:
| Many years ago, I started an ISP. I labelled every cable on both
| ends. My more technical partner came in one day and started
| ripping off the labels. His reasoning? "They're going to be
| eventually incorrect so let's just rip off the labels now and
| trace the connections every time."
|
| It took a while but eventually we went our separate ways.
| ilyt wrote:
| Technically the way to fix that problem is to label cable with
| _cable_ ID then track "which cable connects what" in IPAM.
|
| But then having to look up each cable is a bit of PITA
| hn_version_0023 wrote:
| I feel obligated to say this, even though it should be
| extremely obvious :
|
| As a manager of data center technicians, I would fire someone
| on the spot for this behavior. It is unconscionably stupid and
| entirely unprofessional and unproductive.
| linker3000 wrote:
| Had to learn lacing during my Electronic Engineering
| apprenticeship in the 1980s, but the skill has been little used
| since.
|
| I did, however end up with a large spool of waxed, flat nylon,
| lacing cord, to which I fixed a small metal nut. The cord was
| very light and I could throw the nut (and cord) quite large
| distances through roof spaces and ducts; it was a great method
| for pulling through data cables.
| systems_glitch wrote:
| I hear nowadays they have essentially a nerf gun intended for
| this!
| JohnFen wrote:
| OK, now I need to learn how to properly lace cables and start
| doing it in my own projects. Thanks a lot, HN.
| kuon wrote:
| I use Velcro for all cabling, allowing toollless modification and
| flexibility, but a bit expensive.
| devb wrote:
| It's nice looking. And I'm sure it's satisfying doing it. But
| velcro is better.
| glonq wrote:
| I remember having to wear nice shoes and nice pants for my first
| IT monkey job, then wearing out the toes and knees because I was
| always scurrying around on all fours chasing down problems. Like
| packets spilling out all over the floor because somebody forgot
| to terminate their 10BASE2.
| ofalkaed wrote:
| Lacing cables is one of the few things I miss about electronics,
| but I don't need more stuff so I have nothing to build and I have
| long since grown sick of building stuff for other people.
| zikduruqe wrote:
| I used to run a few telco switching offices back in the circuit
| switched days... and I truly miss wiring up DSX panels. I would
| come in on a Sunday afternoon with music playing and that was
| my zen.
| Gud wrote:
| It's not a lost art! It's still done with high voltage cables, at
| least sometimes.
| ambientenv wrote:
| I was in telecom and IT for 35+ years (Bell Canada, NorTel) and
| worked with on-prem and CO-located step-by-step and crossbar
| switches at the tail end of their prevalence. It was a joy to be
| able to take the time to properly lace cable harnesses which were
| abundant in these installations. There were also PDP-11's,
| teletypes and such involved in network/switch monitoring which
| had their share of laced wiring harnesses (and wire wrap!). Also
| Datapac/Dataroute equipment cabinets and back-planes. It seems to
| me that the job title of "craftsman" fit in those days as there
| was often an almost artisan quality and craftsmanship to the work
| involved. I'm glad to have had the opportunity to experience it.
| Compared to my later datacenter installation experience (compute
| and power) it was night and day different.
| bbarnett wrote:
| _Also Datapac_
|
| /me shakes fists, at naming of Datapac.
|
| I used this to connect to Compuserve, and it dropped endlessly.
| I guess my 300 baud modem was too much for it.
|
| Edit: realization dawns! It was you, wrapping cables, which
| caused my disconnects!
| Aloha wrote:
| You should for sure write about your experiences.
|
| The transition point between EM/Analog Stored Program and TDM
| is important. There is little out there about Datapac at all.
| Aloha wrote:
| Cable Lacing is still mandated by AT&T and (I think) Verizon in
| their facilities. I think AT&T only requires it for power
| cabling, but I'm not 100% certain.
| ckocagil wrote:
| IMSAI Guy on Youtube made a video on cable lacing just last
| month. It shows a few different standards and knots:
| https://www.youtube.com/watch?v=EN8dDR4ipBU
| cuSetanta wrote:
| When working on spacecraft cabling we use a combination of zip
| ties and lacing cable depending on the situation.
|
| Lacing is used to hold a bundle together, fix shielding braid
| around cables and to connector backshells, and sometimes used to
| fix the cabling to the spacecraft structure.
|
| Zip ties are used for more structural tie down points for both
| cabling and small components.
| dclowd9901 wrote:
| > but professional installers know cable lacing lasts longer than
| cable ties.
|
| Come on. Look I love this and it's beautiful but I can't think of
| a single scenario where you need cable lacing to last longer than
| cable ties. My 76 BMW (an almost 50 year old car) uses cable ties
| for its loom under the hood. I'm currently in the process of
| restoring it completely and every single one of those ties is
| still intact, in an environment far less hospitable than a sound
| stage.
|
| The nice thing about this tie setup, it seems, is you get
| bundling it over a distance. Nowadays I think most people use
| nylon webbing for that but this is a cool alternative.
|
| Like, we can love the craftsmanship behind this for its own sake.
| We don't need to ship lies or pretend reasoning with the story to
| sell it.
| ethbr0 wrote:
| I've always wondered, from people more knowledgeable than I --
| Any advice on bundling cable runs, re: crosstalk? Does it
| actually cause issues? For either electrical or data?
|
| Know it's less on a concern with fully-shielded and -terminated
| (Cat6a+?), so this may be a somewhat historical question.
|
| Interested in theory and/or real-world practice and results.
| Links welcome too!
| crote wrote:
| It can definitely causes issues. The risk factors are: - High-
| current power cables - Analog signal wires - Low-voltage signal
| wires
|
| In practice it is mostly a solved issue. Applications like
| Ethernet, HDMI, and professional audio have been using balanced
| signal pairs for decades and they cancel out most interference.
| We figured out how to do that in the 1880s.
| cuSetanta wrote:
| I have spent months of my life trying to diagnose issues with
| spacecraft hardware that ended up being caused by cross-talk
| from a noisy clock signal in AWG30 wires. Added some shielding
| and everything worked perfectly.
|
| In the most recent case, the clock was interfering with a
| series of motors, causing an antenna pointing array from
| getting lost and moving erratically. We had had some issues
| with the motors in the past so assumed it was an issue there
| and performed 100s of tests to try understand the issue. When
| we realised it was crosstalk I was quite red in the face.
|
| In spacecraft we talk a lot of precaution to avoid crosstalk
| when laying out our harness. Shielding is not always an option.
| bluGill wrote:
| If doing long runs just run fibre. gigabit Ethernet is about as
| fast as copper can get - yes 10gb Ethernet exists, but it is
| power hungry (one reason 2.5gigabit starting to appear). You
| can send a lot more data with fibre, there are no cross talk
| issues, and it is cheaper than copper. Transceivers are still
| expensive though, so copper is best for shorter runs (within
| your house distances), but still everyone who might run some
| cable in the future should learn about fibre and how to work
| with it.
| arein3 wrote:
| Fiber through the house is a PITA. The fiber cable is
| fragile, can't be bent and can't be tested/resized without
| special equipment. I wait to end my current contract with the
| internet provider and will switch to a new one that has
| normal equipment that allows to run ethernet trough the
| house.
| simoncion wrote:
| > Transceivers are still expensive though...
|
| 10Gtek sells 10gbit multi-mode SFP+ transceivers for ~10->15
| USD per, depending on how many you buy at once. I have ten on
| my LAN and have had no troubles with them. (Now we "just"
| need to do something about how absurdly expensive 10gbit NICs
| are...)
|
| (And no, I had never heard of them before I bought a few. I
| figured that multi-mode SFP+ transceivers have been around
| for more than a decade, so there's no reason for them to be
| 50->80+ USD per... purchased from several of the cheapest
| manufacturers selling on Newegg, and found that 10Gtek's
| stuff worked fine.)
| ethbr0 wrote:
| I was looking at it. What's the current best home-hobbyist
| option for terminating?
|
| Last I checked, it looked like it made more sense to just buy
| pre-terminated, built-to-length cables.
| bluGill wrote:
| That is one of the downsides of fiber: you need to figure
| out your distances before hand and order the right length.
| One more reason to use copper in the house most of the
| time. Maybe some ~2ft lengths of fiber for use on your
| server rack where you need speed between the server and the
| switch.
| xattt wrote:
| Is it still worth doing Cat 8 for stringing Ethernet in a new
| build, or is it okay to cheap out and just go with Cat 6a?
| bluGill wrote:
| Only time will tell. For now my best guess is cat 5e is
| still good enough for everything, but since cat6a is no
| more expensive may as well use that instead.
|
| God has not given me any indication on how the future will
| play out though, I could be wrong. Then again I might be
| right just because by the time you need more than cat6
| there is a new cat 12 that you need. Only time will tell.
| crote wrote:
| Cat6a can do 10GB over 100 meters, cat8 can do 40GB over 30
| meters. Current consumer hardware is _starting_ to support
| 2.5G over 100 meter of cat5, and we miiiight see 5G over
| 100 meters of cat6 become common in a few years.
|
| If you're _that_ worried about upgrade-ability, better
| stick to fiber.
| toast0 wrote:
| Note that the specs are 100 meters in a dense conduit.
| You can probably manage higher than rated speeds in a
| household environment which likely doesn't have dense
| conduit nor 100 meter runs.
|
| If you're wiring from scratch, sure put the best you can
| afford, but if you've got cat3 in your walls already, see
| what runs, your NICs aren't going to look at the label on
| the insulation. (For better or worse, ethernet speed
| negotation runs at 1Mbps and the specs don't contemplate
| testing conditions and reducing speeds until you get to
| the multi-gig (2.5/5/10g) equipment. Some equipment will
| drop to 100M in drivers though)
| JKCalhoun wrote:
| As a foil, people building point-to-point tube amplifiers are
| very concerned about "crosstalk" in the circuit itself and try
| to have signal carrying wires cross at right angles to each
| other rather than run parallel (for obvious electrical-theory
| reasons).
| [deleted]
| BenjiWiebe wrote:
| But those signal wires aren't balanced twisted pairs.
| bayindirh wrote:
| Gigabit Ethernet doesn't care much if you have a good quality
| Cat5E+ cable. Doing this a lot in the data center for a long
| time. However you don't want high power AC cables going
| alongside with them. Just carry them separately, or keep power
| source local to target.
|
| Similarly, other data cables (Infiniband, SAS, etc.) doesn't
| care either, but they're both short length when used in copper
| form and they have ample shielding.
| crest wrote:
| Lacing cables together isn't worse than running them parallel
| using other means e.g. velcro loops unless you're lacing them
| tight enough to crush the cables.
| ethbr0 wrote:
| From memories of electromag, field coupling from current in
| parallel cables decays with 2*pi*r, no?
|
| So it seems there would be a fair amount of difference at
| extremely low separation distances. But we never worked
| through high frequency EE derivations, which I assume are
| more average-current- or capacitance-dominated in terms of
| effects?
| SAI_Peregrinus wrote:
| The distance between cables doesn't vary much between
| lacing methods. The balanced nature of the signals also
| means the common mode rejection ratio is very high, so
| external EM interference (which almost entirely shows up as
| common mode) isn't a huge concern.
| brk wrote:
| On a decent quality cable you are unlikely to run into any
| scenarios in a typical residential or small business install
| where noise and interference causes a degradation in
| throughput.
|
| The balanced signalling used in twisted pair communications is
| very robust these days, and then you have various protocols on
| top of that which can handle small errors natively (eg: TCP
| retransmissions).
|
| It is highly recommended, and often required by code, to keep
| low voltage and high voltage (high voltage being 120V AC power
| lines, which really aren't that "high" of a voltage) separated
| physically. This can be air separation, keep them several
| inches apart, or conduit separation (don't ever run them in the
| same conduit). This is mostly a safety issue in the case of
| insulation breakdown to keep any high voltage leakage from
| entering the low voltage cable and equipment.
|
| Similarly, things like minimum bend radius, and untwist amount
| at termination can often be wildly violated with no ill
| effects. But, it's still best to not temp fate if not needed.
| Even max cable length can often be exceeded by 20% or more.
| mnw21cam wrote:
| It isn't the voltage that causes interference, it's the
| current. A flowing current creates a magnetic field which can
| induce a voltage in nearby wires that run parallel. It just
| happens to be that the wires that carry the highest current
| are your power lines at high voltage.
|
| If you have a wire carrying a very high voltage but no
| current at all, you shouldn't get any interference from it.
| Likewise, you could have a low voltage cable carrying lots of
| current (though why, I'm not sure), and that would cause
| interference.
|
| Your point about code and safety is separate, valid, and very
| sensible though.
| crote wrote:
| Low-voltage and high-voltage wires are not separated for
| interference but for _safety_.
|
| OPs point is that if a 230V wire _somehow_ got damaged it
| could end up touching the outside of an Ethernet cable, and
| if the Ethernet cable is not rated for that it could cause
| serious damage to the attached equipment.
|
| You either need to keep Ethernet away from power, or make
| power 230V+-tolerant.
| ethbr0 wrote:
| Or just run power over Ethernet, because no safety best
| practices survives market ease-of-use pressure. /s
| jaclaz wrote:
| >It is highly recommended, and often required by code, to
| keep low voltage and high voltage (high voltage being 120V AC
| power lines, which really aren't that "high" of a voltage)
| separated physically.
|
| It depends, there are types of data cables certified
| (insulation above 400 V) to be installed in same conduit as
| mains wires:
|
| https://news.ycombinator.com/item?id=34725851
| brk wrote:
| Until you wind up with an AHJ who doesn't care and requires
| you to separate the cables.
| jaclaz wrote:
| Well, that can happen about almost anything, having data
| and mains cables separated is anyway a good idea, but
| (with the correct cables) is not (anymore) against code
| in many situations.
| brk wrote:
| 100% agree. My main point is that it is a "just because
| you can doesn't mean you should" sort of scenario. There
| are situations where it is allowable, and safe, of
| course, but it would still generally be considered bad
| practice unless absolutely necessary.
| CobaltFire wrote:
| Worked aircraft and nuclear system maintenance/operations for the
| last 20+ years in the US Navy and I can say that cable lacing
| isn't dead there. Some people suck at it, but if we aren't doing
| a full harness build with the sleeving machine then we lace
| everything.
|
| I actually love the craftsmanship of building a proper harness
| up. There is a lot more skill that goes into it than most people
| expect, most of it regarding preventing edge cases (repair needs,
| chafing, EMI interference, signal contamination requiring
| separation...) during operation or maintenance. Lacing 400Hz AC
| into a harness with sensitive analog signals is a mistake that
| will lead to nothing but headaches...
| rascul wrote:
| I've laced cables in the past. It takes a little longer but can
| look nicer if the cables are exposed. Also there's the advantage
| that it's easier to cut the lacing without damaging the cable
| insulation than it is a zip tie.
| kayodelycaon wrote:
| With a zip tie, use a pair of pliers. (I use a multitool.)
| Place them right behind the head, then pinch it on the sides
| and twist. It's important to grab the sides of the tie, not the
| top and bottom. The plastic will rip easily if you do it right.
| (This is also the recommended way to remove the tail end, it
| doesn't leave a razor sharp edge like scissors do.)
| ortusdux wrote:
| Zip tie guns are amazing. They pull to an adjustable tension
| and then cut off the tail. I ended up with a Panduit model
| that retails for $300, but harbor freight's $20 unit works
| very well.
| waterproof wrote:
| My life has changed since I learned that reusable zip ties are
| a thing. They have a little lever you can press to release the
| cam.
|
| They cost more of course, but I'm never going back.
| kayodelycaon wrote:
| It's not worth the effort but you can reuse regular zip ties
| if you have a small flat-end screwdriver. :)
| iso1631 wrote:
| I much prefer velcro. If you do use zip ties don't cut the
| ends. If you do, make sure it's flush, had many many
| scratches over the years from non-flush cuts on plastic
| zipties.
| devenson wrote:
| Or melt the sharp ends with a lighter to dull them.
| 83 wrote:
| Or buy the right tool for the job.
|
| Panduit zip tie guns are expensive, but once you
| experience the joy of having zip ties correctly tensioned
| and trimmed flush with no effort you'll never look back.
| arein3 wrote:
| zip ties have often a sharp finish over the length of the
| zip tie and can cut trough insulation if there are
| vibrations
| Rooster61 wrote:
| I can't help but be reminded of how cuts of meat get tied up to
| prevent them from curling up when searing. Funny that chefs use
| this technique for beef, yet we use it for miles and miles of
| spaghetti :)
|
| All kidding aside, its amazing how a bit of string can be such a
| useful engineering tool in so many contexts.
| qwertox wrote:
| This was always what I found most fascinating about the mars
| rovers. I loved to look at those selfies where you could see the
| laced cables.
|
| I just googled a bit and found a nice one from the inside of the
| Perseverance Rover [0]
|
| [0] https://i.redd.it/8vcspndiaph91.jpg
| 0_____0 wrote:
| I don't see much that looks like true lacing there, mostly a
| metric shitton of kapton with some ties at intervals to keep
| things from shifting around. Which is totally a valid way to do
| it but not really lacing
| masklinn wrote:
| Do you consider only running stitches to be lacing?
| wildylion wrote:
| Oh, this was really common in Soviet radio, military and
| especially aircraft and space industries.
|
| Best part: Russian military stockpiled so much of amazingly
| durable PTFE-insulated cable that I could get miles of it for
| (relatively) cheap. Think anything from 36AWG to 12AWG.
|
| And yes, I often use the leftovers of 26AWG for my projects. That
| thing was something my EU friends were envying endlessly :)
|
| Sadly, with the EU RoHS regulations, I can no longer use this
| beautiful eutectic leaded solder... well, I can and do for
| personal use, but technically this is illegal :).
| detaro wrote:
| > _but technically this is illegal_
|
| How does regulation for commercial manufacture and trade of
| electronic devices make your personal use illegal?
| iso1631 wrote:
| > Cable lacing is definitely old school but it's been the method
| of choice for major broadcast facilities, stage rigging, CATV
| installers, NASA engineers, ships and aircrafts for many years
|
| I've worked for a major UK broadcaster for 20 years, and have
| installed equipment in dozens of core equipment rooms. Early in
| my career I sat next to a Tag frame (which predated krone blocks
| for jumpering audio cables), it was part of an old central
| aparatus room full of analog video cabling from the 1980s or
| before.
|
| I've never seen such lacing. Maybe it's a US thing, but our
| Washington office was built in 2005 and doesn't have it either.
| Cable ties all the way - either plastic or velcro.
| quux wrote:
| Cable lacing seems to be alive and well in aviation. I'm
| currently building a homebuilt experimental airplane and as I've
| started researching the avionics build I've noticed a lot of
| cable lacing on the wiring harnesses all over people's planes. I
| think it's because lacing is lighter weight, uses less space and
| is easier on the wires in high vibration environments.
|
| I do notice a lot more spot ties rather than running stitches.
| Not sure why.
| ryandrake wrote:
| Same here. I just finished up an RV build, and all my wire
| bundles are laced. I chose to use individual clove hitches
| instead of running stitches because it's easier to fix
| individual knots later and, well, I just never got good at the
| terminating knots.
| quux wrote:
| Nice! I'm working on an RV-14A. Still on the empennage kit so
| I've got a long way to go but I'm enjoying the build a lot.
| buildsjets wrote:
| When a single running stitch gets damaged, the entire bundle
| can come undone. Spot ties are failure independent.
|
| Using lacing instead of zipties means there are no sharp cut-
| off ends sticking out to tear up your hands. Zipties can pinch
| and damage insulation, especially when installed with a
| tensioning gun.
| [deleted]
| TedDoesntTalk wrote:
| Why weren't wire ties used? Or twisty ties (the kind used in
| garbage bags)?
| jameshart wrote:
| Individual ties can migrate along the wires, losing the benefit
| of bundling.
|
| Laces ensure the bundle is held together at fixed intervals for
| a long time, even in the face of vibrations, temperature
| changes etc.
| JKCalhoun wrote:
| My guess is -- this would be quicker. Having to stop and twist
| together a new tie every 6 inches vs. just continuing your
| daisy-chain of loops only having to expend any significant
| effort at the beginning and end of the chain.
| gvb wrote:
| Lacing dates back to the beginning of electrical wiring (late
| 1800s, early 1900s)
|
| a) "Zip ties" were not invented yet (nylon was invented in
| 1935)
|
| b) Twisty ties are thin metal wires covered by paper (plastic
| covered ones were not practical until the late 1900s). The
| twisty wires were a threat to cut into the wire bundle. They
| also rust.
|
| Even in modern days with zip ties, lacing has a significant
| advantage in that zip ties have sharp "tails" that stick out
| from the bundle and cut your hands and arms when you reach into
| a compartment. Lacing lies flat against the bundle and has no
| sharp ends.
| calvinmorrison wrote:
| Gotta recommend you get a zip tie gun... Snips and tightens
| at the same time and doesnt leave a sharp point
| pimlottc wrote:
| Interesting, I hadn't heard of those before! I had to go
| look up a video to see how it worked [0].
|
| However, since it uses standard zip-ties, there's still the
| extra bump of the head on the finished tie, which can snag
| if you're pulling on the bundle.
|
| 0: https://www.youtube.com/watch?v=iBP7kMi-mN4
| gregmac wrote:
| > zip ties have sharp "tails" that stick out from the bundle
| and cut your hands and arms when you reach into a
| compartment.
|
| The guy that ran a computer shop I used to frequent was an
| ex-Bell tech, and taught me about using flush-cut snips
| exactly to avoid this. They've been a part of my toolbox ever
| since. They're also my go-to cutting tool when working on
| small electronics.
| jaclaz wrote:
| Lacing was widely used in (industrial) electric switchboards,
| at least here what is used nowadays in them is not so much zip
| ties but rather plastic spirals or similar continuous cable
| wraps, like these:
|
| https://www.hellermanntyton.com/competences/cable-wraps?comp...
|
| Or, in bigger swithchboards, ducts like these:
|
| https://www.hellermanntyton.com/competences/wiring-ducts-hel...
| mberning wrote:
| Depending on the environment zip ties, wire ties, etc. may not
| be appropriate. For example, high heat and UV exposure can
| cause zip ties to fail rather quickly.
| tracker1 wrote:
| Sorry, I'll take velcro zip ties...
| [deleted]
| mdip wrote:
| If I care about what it looks like and want to precisely arrange
| my cables, I always lace. It's time-consuming, finger-aching
| work, though and I'm not as good at it as I was when I was
| younger[0].
|
| In my late teens, I worked at a telecom in desktop support and
| ended up on a multi-day project installing hardware at a switch
| site in Cleveland. They'd taken on a new director who was furious
| at the condition of the cabling/cable management[1]. I remember a
| piece of paper with a _sliced_ black zip-tie taped to it and the
| words "FIRED" scrawled in big letters. Teams of two men were
| working throughout the site.
|
| They were ripping out/replacing a huge number of runs. During the
| week, a group was working on a bundle of what looked like
| thousand Ethernet cables coming from the ceiling, all labeled,
| starting out as a perfectly laced 3x2 ft rectangle through the
| channel in the ceiling and then falling into a spaghetti pile
| extending most of the floor of the large room.
|
| By the time I left, that channel was nearly done, the wires broke
| off at 40 or so points in different bundles ranging in size, but
| most were inches thick/wide, wires joined the bundle at various
| points in the metal channel causing the wire bundle that went to
| the floor, below, to be only a little smaller than the one coming
| in. Every curve of every bundle was visibly the same radius.
|
| After seeing what _could_ be done, I decided to learn how to do
| it. :)
|
| [0] I'm not that old.
|
| [1] Some of the issues were straight-up code violations, but most
| were issues of good practice.
| ilyt wrote:
| > If I care about what it looks like and want to precisely
| arrange my cables, I always lace. It's time-consuming, finger-
| aching work, though and I'm not as good at it as I was when I
| was younger[0].
|
| I just use zip-ties. What is the advantage of lacing ?
| gregsadetsky wrote:
| I'm not a pro at this at all, I've only done amateur small-
| scale cabling jobs.
|
| If I understand correctly, the arguments against zip ties are
| that 1) it's easy to overtighten them, which can lead to
| damage to network cables 2) they're obviously irreversible so
| less flexibility in the future?
|
| Am I overthinking this? There must be standard cable
| management practices (that are either pro/against zip
| ties)... can anyone recommend a guide?
|
| ---
|
| For what it's worth, found this:
|
| https://electrical-engineering-portal.com/res2/Best-
| practice...
|
| Use cable ties to hold a group of cables together or to
| fasten cables to other components. Choose Velcro-based cable
| ties versus zip ties, as there is a tendency for users to
| over-tighten zip ties. Over-tightening can crush the cables
| and impact performance.
| wl wrote:
| If you're using a lot of zip ties, you really need a zip
| tie gun. Not only do you get a consistent tension, but you
| also trim the excess at the same time.
| cuSetanta wrote:
| Love those things, a lot of fun to use and always get
| perfect results. They have some very nice ones with
| spinning heads to reach ties in difficult locations too.
| sandworm101 wrote:
| Zip ties move. Lacing points are all attached. They don't
| slide along a cable like loose zip ties.
| readingnews wrote:
| The person that comes behind you (or you) who cuts the ends
| of the zip ties off has never stuck their hands back in
| there, I bet. In tight spaces, the cut off zip ties become
| nice little knives, and will cut your hands when the zip ties
| are large. We did this on industrial equipment panels, and
| had to stop due to techs coming in after us and cutting
| themselves up in tight spaces.
| cuSetanta wrote:
| In the space sector the mass savings over a whole spacecraft
| can really make a difference, and lacing doesnt introduce and
| hard edges that can lead to fraying or wear from vibrations.
|
| Additionally, lacing cord typically can handle much higher
| temperatures than space-rated zip ties.
| krupan wrote:
| The linked article has your answer
| brycedriesenga wrote:
| It says the following, but I still don't get it. How does a
| hook-and-loop tie add that much more obstruction that it
| could be an issue?
|
| "This old cable management technique, taught to generations
| of linemen, is still used in some modern applications since
| it does not create obstructions along the length of the
| cable."
| jiggawatts wrote:
| While I too love to see good cable layout, whenever you see a
| "thousand" Ethernet cables in one run, a foundational mistake
| has been made.
|
| Instead of 1000x 1 Gbps links, the proper way is to consolidate
| those into 10x 100 Gbps links or whatever works out to be the
| cheapest given the length of the run, the cost of the switch
| ports, etc...
|
| Any argument to the contrary has a solution. E.g.: even multi-
| tenant links with overlapping address spaces can be handled
| with nested VLANs (VXLANs). This is essentially how cloud
| providers and large metro network provides handle multiple
| customers.
|
| The last time I saw cabling like this was at a government
| department with "network techs" that didn't get these basic
| concepts. Instead of having "top of rack switches", they had
| one giant pair of switches in the corner of the data centre
| with bundles of cables coming out the thickness of my torso!
| The same department had a long building with switches in one
| corner and bundles of cables in the ceiling going to desktops
| over 100m away.
|
| In all cases this was done neatly.
|
| They loved cable porn, but didn't understand networking!
| teepo wrote:
| I like the old Softlayer / IBM Cloud cabling scheme: dual
| 10Gbps to TOR (red)and BOR (blue) and the 1Gbps green cabling
| into the IPMI. Here's a pic: https://newsroom.ibm.com/IBM-
| cloud?item=32774
| seanc wrote:
| No mention of the legendary NASA cable lacing guide?
| https://workmanship.nasa.gov/lib/insp/2%20books/links/sectio...
| voxadam wrote:
| I'm sorry, I actually meant to include your link when I
| submitted this. NASA's wiring documents are beyond amazing.
| ape4 wrote:
| I am happy to know if any NASA spaceships are intercepted by
| aliens that they'll have good quality lacing to represent us.
| VLM wrote:
| Good quality lacing means the craft will probably be working.
|
| The worst case scenario is a tangle of cables hanging all the
| tension on one individual cable then apply a nice 9 G load
| with vibration and it snaps.
|
| Also good lacing in minimal volume which means maximal
| cooling air flow in general.
| nick123567 wrote:
| Depends on if you laced the wire that needs the most
| cooling deep in the center of the bundle...
| cuSetanta wrote:
| Its also important during the building process to keep the
| rats nest of wiring to a minimum, it can get fairly messy
| inside spacecraft. Then its also much easier to ensure
| cabled are kept apart from other signals that could
| interfere with them.
| cuSetanta wrote:
| Use this and the other NASA workmanship guides all the time. A
| really great resource for building spacecraft.
| nix23 wrote:
| Ehhmm, thank you very much for the link!! Wow!
| Wistar wrote:
| See also this guide, reproduced from a book _" Workmanship and
| Design Practices for Electronic Equipment",_ published by the
| direction of the chief of the _Bureau of Naval Weapons,_
| December, 1962. Included are some illustrations of jigs for
| creating laced wiring harnesses.
|
| https://www.dairiki.org/hammond/cable-lacing-howto/
| readingnews wrote:
| When I was a grad student in Physics I worked at an accelerator
| lab where we had an old NASA high voltage engineering unit. The
| control panel was completely laced, every wire had a marker on
| it every foot or so, every end was perfectly terminated. Being
| an electronics tech, it was a dream to work on this thing...
| Wish I had pictures. But as others have noted, it takes a great
| deal of time to do that right when you are installing.
| digitailor wrote:
| In the author's defense they mentioned the NASA standard, and
| that guide-- while legendary-- isn't a "lacing" guide. Of the
| 50+ images, only 2 show lacing (acceptable v. unacceptable),
| and the rest is spot tying, zip tying or other harnessing.
| Always nice to see the link though
| luma wrote:
| > Some organizations have in-house standards to which cable
| lacing must conform, for example NASA specifies its cable
| lacing techniques in chapter 9 of NASA-STD-8739.4.
|
| It's right there in the article.
| Aromasin wrote:
| I shared this article a few years back; never expected it to
| reappear again.
|
| Here's the link to the old thread, if anyone want to read the
| previous HN comments:
| https://news.ycombinator.com/item?id=20582844
| dang wrote:
| Thanks! Macroexpanded:
|
| _The Lost Art of Lacing Cable (2018)_ -
| https://news.ycombinator.com/item?id=20582844 - Aug 2019 (153
| comments)
| rtp4me wrote:
| In my experience, data center cabling is either a huge mess
| (random cables just hanging everywhere) or is tied down so much
| you can't do any repairs/replacements (velcro, tie wraps, etc).
| There is a fine line between cleanliness and usability.
|
| For the folks that work with me, I explain the importance of air
| flow, proper cable length, and component serviceability. You
| definitely don't want "piano wire" stretched across the rack that
| prevents someone from replacing a PSU or NIC without affecting
| other gear in the rack.
| walrus01 wrote:
| one of the key things to do in a 'serious' datacenter is
| separate the fiber from the power.
|
| this is why serious facilities have a dedicated channel of
| yellow plastic overhead fiber tray which contains ONLY 1.6mm or
| 2.0mm jacketed 9/125 singlemode fiber, with nice smooth corners
| and spigots on it coming down above racks.
|
| and then the AC power is in conduit and long rectangular metal
| enclosures.
|
| and the -48VDC cabling on steel ladder rack, often with waxed
| string lacing if it was done by people who are being serious
| about it.
|
| on a per rack cabinet level it's also really important to pick
| one vertical side for your power cables, and data cables
| vertically up the OTHER side, and stick to it consistently.
| gtfoutttt wrote:
| Why is this? Does power interfere with the fiber?
| walrus01 wrote:
| No, not at all, it's for proper organization, management,
| labeling, flexibility to add and remove things, etc.
| [deleted]
| [deleted]
| ilyt wrote:
| Then you get a bunch of boxes where "connectivity" and
| "power" is on opposite side than the other boxes ;/
| systems_glitch wrote:
| We often end up with AC power down both sides for A and B
| busses. Prefer the "zero U" type solutions for that.
| Zircom wrote:
| My first real IT job was doing all the grunt work (and whatever
| sysadmin tasks I could talk the greybeards into trusting the
| new kid with) in our two DCs, one at the corporate office and
| the other at our manufacturing plant.
|
| Our DC at the corporate office was OK aside from the patch
| panel which was a fucking mess, that and when they originally
| built the thing however long ago they installed the switches at
| the top of the racks BACKWARDS so the ports where at the FRONT
| of the rack instead of the back with the server ports and they
| just ran with it instead of taking 20 minutes to flip them
| around, so instead of neat orderly cables going up and down
| between the ports you had these giant bundles on either side of
| the servers going from front to back I had to unbind and
| untangle anytime one needed replacing >.> This[0] is the what I
| managed to get our patch panels there reduced too and slightly
| cleaned too after removing all of these[1] cables that were
| still plugged into dead ports that my predecessor just never
| bothered to take out after retiring or recabling servers that
| had been on the other end. I'm 99% sure he was just running new
| cables and configuring a new port anytime someone called to
| complain about an unreachable server instead of trying to find
| the other end of the relevant cable.
|
| [0] - https://i.imgur.com/PIPhAal.jpeg [1] -
| https://i.imgur.com/PIPhAal.jpeg
|
| Wish I still had some pictures of the plant DC though because
| holy cow it was even worse, no patch panels anywhere, but they
| did have a drop floor so I could pull the tiles up and run
| cables down there if I was so inclined. My predecessor, not so
| much. He seemed to prefer running them between the tops of the
| racks, with random cables crisscrossing above your head, always
| drooping down and getting snagged on the step ladder as I
| carried it between racks, or getting caught in the doors
| constantly. And they would never let us have any downtime to
| clean up the cabling, nor could I talk them into just switching
| the network configs to use a different damn port on the actual
| servers so I could just run new fucking cables ;_; I had to
| settle for obsessively tracing and labeling each end of the
| cable with the port# and device that was on the other end of
| the cable, because otherwise every call about checking on a
| server turned into an hour of either tracing cables either
| under the floor, pulling tiles one by one to follow it to the
| other end, or a jungle safari sorting through the tangled mess
| of cables on top of the racks following the one in question as
| it arced over multiple aisles to it's final destination. Which
| of course I had to do anyways to get them all labeled, but at
| least this way I only had to do it once and it was done
| forever.
|
| Good times.
| Bluecobra wrote:
| > long ago they installed the switches at the top of the
| racks BACKWARDS so the ports where at the FRONT of the rack
| instead of the back with the server ports and they just ran
| with it instead of taking 20 minutes to flip them around
|
| There might be a good reason for this, it sounds like they
| messed up the switch order and got front to airflow switches.
| Normally you would buy rear to front airflow, as the front of
| the cabinet is the cold aisle and the rear is hot.
|
| In a shared colocation like Equinix, they will make you
| conform to these standards and have you rack a switch that
| way so the airflow is correct. Incorrect airflow lowers
| cooling the efficiency of a DC.
|
| Front to airflow switches still have their place though, you
| typically find them on two post telco racks where the patch
| panels are.
| Zircom wrote:
| They definitely just didn't care enough to mount them the
| correct way, I have very distinct memories of getting
| blasted in the face with hot air any time time I was
| standing in front of the racks. I'm reasonably tall and
| have longer hair, and the top U of the racks was juuuuust
| high enough so that my hair would be whipping around the
| entire time.
| em-bee wrote:
| [0][1]: both links are the same.
| Zircom wrote:
| Crap you're right. Here's the pile of removed cables.
|
| https://i.imgur.com/PLCphKA.jpeg
| systems_glitch wrote:
| Square D panelboards, classy place :D
| em-bee wrote:
| looks like the floor of a hairdresser.
| vidarh wrote:
| Couldn't agree more.
|
| And the latter (tied down) quite often devolve to the former
| over time exactly _because_ it 's so much effort to maintain
| that suddenly an urgent repair happens and ties get cut and
| cables torn out and something new just thrown in, and the
| effort of re-doing the original setup means it gets deferred.
|
| I stopped tieing cables together years ago for that reason. The
| more the perceived effort in getting what needs to be done out
| of the way + fixing the cabling afterwards, the less chance it
| gets done properly. Instead I'd aim to set an example of
| stretching the cables out of the way, labelling and getting
| length roughly right that is simple enough to work with in a
| rush and trivial to "fix up" afterwards.
|
| In _large_ environments where crises are more likely to
| involved routing traffic away from entire racks or data
| centres, you can afford being a stickler for these things. Most
| places are not that large, and being too strict creates more
| problems than it solves.
| gertrunde wrote:
| A particularly frustrating variant of the 'piano wire' issue:
|
| A redundant pair of devices, except cables have been run in
| such a way that if one device failed, you could not remove it
| from the rack without removing cables from the remaining
| device.
|
| /facepalm
| ilyt wrote:
| > In my experience, data center cabling is either a huge mess
| (random cables just hanging everywhere) or is tied down so much
| you can't do any repairs/replacements (velcro, tie wraps, etc).
| There is a fine line between cleanliness and usability.
|
| We have 7 racks that went thru some changes and never in the
| history (12+ years) needed to replace any broken ones. It just
| doesn't happen.
|
| What did happen were re-wires when some hardware were replaces
| but smaller ones were small enough that whether it was nicely
| bundled "permanently" or not didn't matter much, and bigger
| ones were "take everything out and recable" job anyway so
| again, what was in the rack (and there were some spaghettified
| ones too) also didn't matter.
|
| Yeah routing it properly the first time helps but making it
| "permanent" by tying it down isn't really a problem, just put
| another bundle for next 5 servers.
| JohnClark1337 wrote:
| [dead]
| jonhohle wrote:
| Is there any good resources for learning more about this? I
| have a lot of legacy AV equipment mixed with modern digital
| components and networking and despite best efforts, I typically
| fall into either a rats nest or something that's too
| constrained to repair/modify without undoing everything.
| Zircom wrote:
| I mean honestly there's not too much expertise involved, it's
| mostly common sense. It's just that it takes so much longer
| to do it right at the beginning to ensure its maintainable
| and ordered rather than just doing it the easy way and hoping
| that it's someone else's problem by the time someone actually
| needs to find the other end or replace a cable.
|
| Making your own cables that are the exact length they need to
| be instead of using preterminated ones and just stuffing the
| slack into the side of the rack, routing them down the side
| and through the floor or the cabling trays on the ceiling,
| standardized naming schemes for labeling devices/ports on
| either end of cables, documented rack diagrams, etc.
| chasd00 wrote:
| i once had to make up about a 100 ethernet cables of
| varying lengths at once. Man, untwisting, sorting, and
| separating the individual wires to insert into the
| connector before crimping made for some very sore fingers.
| rtp4me wrote:
| Not sure of any specific resources, just years of running
| cables :-)
|
| Some of my lessons learned:
|
| * Whatever you do, be very mindful of future events (repairs,
| replacements, etc). Spending an extra 5mins upfront when you
| are in a hurry will save you lots of time later.
|
| * Label each end of the cable if possible. It is a PIA in the
| beginning but will be a real life-saver when you need to do
| maintenance
|
| * Replace old (fat) cables with new, thinner cables _of the
| proper length_ when possible. I typically add 1ft extra to
| any cable for a little slack.
|
| * Think of airflow. Lots of cables bundled in the back of a
| rack can seriously cause airflow issues. Try to run all
| cables along the sides of the rack.
|
| * NEVER run cables across the back of gear - especially for
| multi-node chassis that require rear access for maintenance
|
| * Velcro is your friend.
|
| * Stick with a cable color standard if possible. For me, I
| use white for IPMI, blue for data, red for external access
|
| * Keep an updated diagram in the rack for the next guy/gal
| who needs to do work
|
| * Always remove old/un-needed cables after a maintenance job.
|
| * Keep the rack clean!
| dontbesquare wrote:
| Velcro is your friend. So much this!
| systems_glitch wrote:
| Abandoned-in-place wiring is the bane of every tech's and
| installer's existence. It's impossible to have worked on
| legacy equipment and not spent some time reterminating
| abandoned cable :/ Not to mention having to weed through it
| when tracing problems.
|
| We're in an ongoing battle with abandoned-in-place wiring
| in our current building. There's data wiring back to ARCnet
| (93 ohm coax), and power wiring going back to knob and tube
| days.
| h2odragon wrote:
| > 93 ohm coax
|
| ooo nifty. be on the lookout for vampire taps. they never
| truly die.
| rtp4me wrote:
| Wow - vampire taps. That brings back some memories :-)
| jcrawfordor wrote:
| "Finger duct" is often the easiest way to get relatively
| clean results in a situation like AV where cabling is sort of
| poorly standardized (connections front and back, inline DC
| supplies, etc). It's fairly cheap and often run vertically on
| rack posts and horizontally above and below cable-dense areas
| like patch panels and switches, but in an AV situation you
| probably only need one vertical channel to get a big
| improvement in results. Finger duct can get pretty messy
| without planning but I think it's usually the best results to
| effort ratio.
| systems_glitch wrote:
| Often used inside industrial equipment as well. Routes
| pneumatic lines pretty good.
| yourapostasy wrote:
| There are still ample supplies of lacing cords for example at
| McMaster-Carr [1] so there likely are still lots of sites using
| them.
|
| The part I never quite understood is why lacing standards didn't
| specify tucking a tail of cord at the end under a single winding
| of two or more whippings so one can exercise the future option to
| expand the loop locks if necessary to insert more cabling instead
| of re-doing the entire lacing run from scratch. I've also yet to
| find proper waxed whipping thread that is a smaller diameter than
| the lacing cord so the loose end of the wound whipping fits
| inside the winding without a snag-prone bulge at the end of the
| lacing cord; I have to messily make my own from 80/3 linen (or if
| lacing outdoor cabling, UV-rated polyester) fine sewing thread
| and beeswax.
|
| [1] https://www.mcmaster.com/products/lacing-cords/
___________________________________________________________________
(page generated 2023-03-07 23:00 UTC)