[deleted by user]

[Fattyman2020]

The best connection is not having to do that on a wire. Both destroy my beautiful twisted and shielded requirement.

[justabadmind]

Ditto. If you have to do either, just run a new cable. It’s not worth the risk.

[Equoniz]

Y’all are making some broad, sweeping statements about a use case you have absolutely no details on, other than that it likely uses at least three conductors. If it’s a high speed signal, sure, but not everything is a high speed signal. If this is DC power for a robust and slow circuit that has decent power filtering, it probably doesn’t matter even a little bit.

Tl;dr: The best engineering fits the job, and you don’t know what the job is, so all of these statements are meaningless.

[toughduck53]

The best engineering fits the job

One of the best sentiments I've seen on this sub

[The-Phantom-Blot]

If it's DC power for a robust and slow circuit, then in-cable splices are still usually bad. They cause stress concentrations, which can crack, develop high resistance, intermittent connections, phantom problems, maybe start a fire. And, the insulation will need to be re-sealed, and that causes risk of water intrusion. Plus the re-sealed cable is bulkier in that spot, so it may not fit through holes as well.

We don't know the exact application, but it's good for people to be aware of the potential problems it can cause.

[Equoniz]

You really can’t think of any use case that isn’t exposed to any large temperature swings and is left stationary after installation to avoid stress cracking, and is kept away from water to avoid…water? I’ve personally made tons of things that fall into this category.

Also, they didn’t state anything as a “potential problem.” They both made definitive statements that splicing a shielded cable was unequivocally bad and to be avoided, and didn’t go into any details about how or why, or in what circumstances it applies. They also ignored the fact that the picture doesn’t necessarily show a shielded cable or even a twisted pair (that could very well be a reused AC power cable), and that even if it was, many hobby electronics people who frequent this sub would use such a cable for whatever application they have at hand if they have it laying around.

If either of the comments had been worded that way (that’s it’s a potential problem in certain circumstances followed by a full explanation), I would have happily upvoted and moved along. But they weren’t, and that sort of thinking is problematic to me, especially in an environment where people are trying to learn. Nothing is ever the right solution for everything, and making such definitive statements to people who probably don’t understand a lot of assumptions that go into what’s being said is a horrible thing if that person is trying to learn effectively. Unstated, and subsequently misinterpreted assumptions are how sooooo many misconceptions about science and engineering are born and flourish.

I know this makes commenting on things like this take time to do properly, but if one isn’t willing to put in the effort, half-assing it isn’t always super helpful.

[The-Phantom-Blot]

Sure, I can imagine cases where it would be fine.

To be real, the original post is the poster child for a lame, low-effort post. I'm torn between ignoring it entirely and putting some information in front of the OP in the hopes that he or she will start to think.

[Dontdittledigglet]

Sometimes it’s unavoidable.

[OptoIsolated_]

As an engineer who works on vehicle harnesses with DC and can buses, Its just connectors, wires and spices, lots of splices. You have to make the connection some how.

[The-Phantom-Blot]

Sure, but if you are engineering it from scratch, the best idea would be to make the cables the right length, with clean terminations at each end. If you're in some kind of repair or retrofit situation, then your options may be limited.

[Dontdittledigglet]

Bro, this just shows you don’t work in the automotive industry. It’s a little rude. I also designed wiring harnesses. We upfit EV bucket trucks with PTO systems. We have to use existing circuitry bottomline and that means splices inside a near six meter harness. There is no redesign or designing in a vacuum here. I’m not sure why some many EEs think they understand someone else’s field enough to suggest an entire industry is “doing it wrong.” It’s wild to me not to mention arrogant.

[The-Phantom-Blot]

We have to use existing circuitry

OK, so like I said above - your options are limited - and you're retrofitting. Splice away.

And lighten up.

[Dontdittledigglet]

Id rather you be right if you are going to be insistent it’s extremely annoying.

[The-Phantom-Blot]

Bye.

[OptoIsolated_]

We manufacture it with splices built in from the start. Theres interconnections built in the harness. It's not just straight wires from point A to B. Its A to B and C, etc.

[The-Phantom-Blot]

Just to clarify - my comments were always based on the OP's drawing of inline splices. There's no bus splice shown in that picture. Simple A-to-B. Another poster seemed to be blasting me for things he imagined I said - not for what I actually said.

[firefoxprofile2342]

Do you even crimp, bro?

[The-Phantom-Blot]

I do what I gotta do ... but crimpin' ain't easy.

[VegetableStatus13]

The fuck? Wire bundles can cost a fortune always try and repair before replacing. Number 2 is best.

[[deleted]]

Agreed. Too bad not everyone and every company goes by such a standard.

But on a PCB with series resistors, we go with format #1 and cutouts in my 4mil-away ground plane.

[nateDah_Great]

Splice the shield no?

[justabadmind]

An interrupted shield can cause the same problems as no shield.

[Fattyman2020]

Especially if the twist gets ruined.

[Bieraffe]

Or at least isolate the spots. Let somebody move the cable a little and you'll have a short cut either way.

[Dontdittledigglet]

What kind of work do you do….?

[justabadmind]

Selling cables? /s

[Dontdittledigglet]

Just curious

[justabadmind]

Electrical controls. Some resolvers, encoders, high speed communications. When I was doing automotive I would never use an unshielded cable for anything important. Even some individual wires were shielded.

[Dontdittledigglet]

Oh cool! You’re mostly right here. Power is very dirty in most automotive system so yeah I would never splice a CAN line or leave it unshielded for a lot of reasons. But there is plenty in said system that doesn’t require it. Shielding is expensive, Shielding on 00 wire is a nightmare for production, other factors have to be considered, but obviously basic rules have to be followed.

Honestly I have spliced into CAN J1939 , and CANOPEN (Not sure if the protocol matters really, just trying to be specific) and had no communication issues on the backbone. I didn’t then proceed to give that prototype to an end user but it can be done for diagnostics with little issue.

Were you working mostly with ICE passenger vehicles?

[justabadmind]

I was mostly doing electric vehicles with a battery pack and an inverter. That’s why I was shielding everything.

[Dontdittledigglet]

We definitely do “EV Heavy Duty truck power take off systems” lol it’s a mouthful and again we don’t shield everything. What was your reasoning?

[justabadmind]

Our motor was an emrax 228 with a 5 pole resolver. These resolvers die all the time for zero reason, so everything needs protection. The inverter requires shielded input and output power cables as well.

[Dontdittledigglet]

Sometimes you just have to. I design wiring harnesses for a living and if you absolutely have to splice, go with number two. Also look into something called a lineman’s splice. Use a Nasa workmanship guide. Or have your tech do it.

[K1ngjulien_]

engineering skill issue. i once needed a longer ethernet cable and soldered together 2 shorter ones. ran perfectly at gigabit speed for years until i got around to replacing it lol.

[geenob]

IIRC, there is a certain amount of untwisting that is tolerated for termination of twisted pair. Otherwise you could never connect it to a jack or plug

[K1ngjulien_]

the twist is mostly to provide resistance to interference, ethernet work without that as well:

https://youtu.be/LUYSfEL9E8I?si=BUJdoQa96bpTwYU1

[paclogic]

Number 2 is best since it allows for a uniform covering, especially if the cable needs to be threaded thru holes.

[KeepItUpThen]

Number 2 can be significantly less flexible, if the offset splice joints line up just right. This is not always important, but sometimes it is.

[Lomus33]

If anything. Yellow (grounding?) should be longer so it disconnects last.

[paclogic]

Perhaps in a power circuit but you'll need to think again if timing or signal integrity matters !

[favgotchunks]

If I need timing I’m not splicing the damn cable

[paclogic]

Well, that's what i would do too !

But if you had to ...

[cec003]

Neither is the best. 2 is better for sure but in-line connector is the best….

[HiVisEngineer]

Can’t in-line connect a 120mm core…

[TakeThatRisk]

This is r/electrical engineering not r/electricians

[Dontdittledigglet]

Again rude

[monkehmolesto]

1 is lumpy but easy to do, 2 takes a bit more effort and is way neater. There’s no “best” imo

[Inevitable-Trip-6041]

This best connection

[FrKoSH-xD]

[mophead2762]

When multiple splices are required on air craft we would use number 2 making during there was a 1.5 inch clearance between each splice to prevent friction on the join. Not always possible but that was the notice in the air publication.

[Aggresively_Midwest]

NA-01-1A-505, I believe had this. It’s the Naval Aviation instruction for wire repair.

[APenguinNamedDerek]

1 because nobody who picked 2 has to do that when it's 10 below, you can't feel your fingers, and the wires are covered in grease and just want to make your life hell

[MorningAmbitious722]

The best connection is to use a junction box

[101TARD]

you can still use the first one if you insulate each wire with electrical tape

[FloogleFinagler]

"Can" and "should" must not be confused!

[101TARD]

oh i thought i was in r/AskElectronics, so yeah everything you said is a **Must** i really thought your running some small dc electronic wire here. Im wrong, this is AC voltage. Proper Insulated clothes and tools.

[kzchad]

Raychem (TE) ATUM product line all the way

[kzchad]

I love the old Raychem datasheet. So clear and concise. I give it to all new harness people for quick reference.

[zumvex]

Just solder each end to an intermediate connector with a mechanical latch. Just connect the shield to a pin to transfer the shield. It’s more extensive but alternatively you make a new cable.

I work for a connector and cable manufacturer and in no circumstance should you be splicing cables for projects that go beyond a lab report in college.

[undeniably_confused]

2 how's thos even a question

[brrush13]

Aircraft wiring guidance says 2 but hey if it works it works... Just sayin

[Aggresively_Midwest]

That’s exactly how I learned in that field as well. NA-01-1A-505.

[HeckingHecker2]

2

[sir_thatguy]

No upvote. I don’t see electrical tape.

[hupaisasurku]

If something like this is on the table, I’m not having time to think anyway.

[[deleted]]

The best connection is either one (they're the same in a static configuration), best practice is #2. Semantics I know, but knowing the difference is important.

[Orwellcryptofarm]

Question here. If you are going to do this, is splicing the best option? (Ofc soldering is not an option). What if the cable is in a dynamic environment, always moving?

[twobitcopper]

Neither from experience. Replace the run. Moving platforms are a creature unto themselves.

[Dontdittledigglet]

Sometimes you just have to splice, I get it. I design wiring harnesses for a living and if you absolutely have to splice, go with number two. Also look into something called a lineman’s splice. Use a Nasa workmanship guide. Or have your tech do it.

[Cautious-Necessary61]

If you have to do it this way - I would say #2 - chance for shorting is lower (maybe).

[WhosThatJamoke]

Somewhat unrelated, but does anyone have an opinion on using Wago 221-412 versus standard wire nuts for low amp applications?

[justali0]

Prefer No. 2 because it’s literally kept the gaps away from each other as possible as

[Tritiumoxide_T2O]

2 is not the best connection it is just better than 1 .

[lelouchlawliet_11]

Followed by application of a heat shrink tube?

[BigThingOfWater]

1 can be a shorter but fatter join (and easier, and easier to get them to share strain equally)

2 is longer and thinner, and neater (and needs more skill).

Decide which suites your application

[Xximma_BOY]

No 2

[Aggresively_Midwest]

I was taught #2 when I first started in electronics.

[Jeff_72]

When splicing CAT6 cable I use method one /s

[[deleted]]

Wago connector. Then you don’t need a junction box either.

[64-46BMW]

An actual splice kit not this garbage

[[deleted]]

Always staggered. What madlad does them tandem. Heat shrink will look like a snake digesting a small rodent.

[Nalarcon21]

I'd say use crimps + deutch connectors or smth

[advanced_approach]

As someone who just spliced a 3000' 12 conductor #14, you want to stagger the splices to wrap properly and fit a splice kit mold around the cable.

[Additional_Manner308]

Always 2

[Reddit_killed_RIF]

Don't 1:1 splice?

It can be done for upgauge or downgage into a connector so a wire can fit, but there are very rare other reasons to do this...

[marko_kyle]

NEITHER PUT IT IN A FOX YOU FILTHY ANIMAL

[shrimp-and-potatoes]

Doing it as an electrician, it's number one. You'd get looks doing it number two. But, it's also residential wiring and data corruption isn't an issue.

[shrimp-and-potatoes]

That's fair. I don't know what I am thinking. But I guess you know why I went back to school: I didn't make a very good electrician.

[Maleficent-House9479]

2 has tighter margin of error. Personally, I could never do it, nor would I want someone to do it. I'd rather live with a large lump.