Wire harness sheathing

[Hindsight]

What's better, the braided type or the corrugated plastic type?

[Jaime]

I don't like the corrugated stuff - it's not waterproof, not heat resistant, not very flexible, and ugly. Braided sheathing looks good and is flexible, but really only serves to keep the bundle together. Heat resistant sheathing should be used near the engine and transmission. If you go braided make sure to get the type that you can remove easily.

I've been lacing my wire bundles where I don't need heat resistance. It makes testing and repair easier and looks high-tech. Removing and re-lacing is pretty easy and most wire tracing and testing can be done without disturbing it. Plus, you can buy a lifetime supply of cable lace for the price of twenty feet of sheathing.

[68GT500MAN]

I do not like the look of the plastic type of sheathing. I went with black electrical tape on my roadster and I am using the braided stuff on my 33.
Doug

[Bob_n_Cincy]

I used the split braided loom. I liked the results and ease of modifying.
Bob

[carlewms]

I like the braided version better. You can get it in a variety of sizes and temperature/heat resistance. It can purchased as a split type as well which makes adding or removing wires a whole lot easier.

What I did find is that the braided wrap that is heat resistant is solid ... meaning no slit to use to wrap it around the wire. With that version you have to start with a clean end (one without a connector).

The standard braided wire wrap comes in two versions ... one is solid and the other has a slit to allow a wire bundle already connected to be loaded into the wrap. The wrap is "spring loaded" to the shut position so to speak and to a certain extent it expands or contracts depending on the number of wires it is carrying.



While one could insert the wire bundle by hand, they make these cool little tools to make it easier.



With this system one could theoretically retrofit a system that exists on the car as long as you could detach the loom along the path.

I purchased a kit (Painless Performance PowerBraid Wire Wrap 70921) from Summit because I needed more of it to do my own harness for the ISIS installation. I found that you can get heat resistant versions from McMaster-Carr or DelCity.

Carl

[Hindsight]

Thanks everyone for the replies

[Boog]

I found that you can get heat resistant versions from McMaster-Carr or DelCity.

Carl

Do the heat resistant versions protect the wires from heat? Or just keep the wrap/braid from melting? It would be great if you could pass along a link to what you are referencing.
Thanks.

[carlewms]

Here is the information from my build thread on the option I used. I really don't think the standard braiding will be a problem, but I figured it was easy to do now versus later.

All the wiring from the POWERCELL is routed to the loads and the CAN cable is routed to the front POWERCELL. As these wires pass over the headers/exhaust piping, I first used high temperature expandable Sleeving to protect the wiring from the heat and then covered them with standard split braided wire wrap to protect the beige colored insulation and keep to the same overall appearance of having a black cover on all the wiring.



The sleeving was sourced from McMaster-Carr:

8994T13 1 Each High-temperature Expandable Sleeving, 1/2" Id, 10' Long
8994T11 1 Each High-temperature Expandable Sleeving, 1/4" Id, 10' Long

Here is a photo showing how the high temperature expandable sleeving is under the split braided wire wrap



Here is a shot of the completed installation on the front of the DS foot box



I used the access point normally reserved for the clutch cable to enter into the DS foot box



This may be over kill on the wiring protection...

Carl

[carlewms]

Here is some more information on the braided wire looms ....







Hope this helps ...

Carl

[Boog]

Just what I was looking for.
Thanks for your help.

[Scargo]

I was thinking in terms of using something like either 3/4" Raychem DR 25 @ $4.5/ft. or cheap out with 5/8" non-shrinking, black, PVC @.$1.72/ft. for my main wire bundles.
I want to get the benefit of more water and chemical resistance for my wires. I see the possibility of the interior getting wet or oil or gas getting on wiring... Is there a downside to this approach? I don't see anyone doing this.

[aquillen]

I agree on trying to keep bundles of wires (harness runs) bundled up and dry. It can be real challenge though. The ends - water or whatever gets in there - it stays for a long, long time in many cases. If you go with a solid cover like shrink tube, then you probably want to address sealing the ends. About the only ways to be effective with that (and I've done this before on equipment) is work silicone sealant into the bundle near the end, so when you shrink tubing, it squeezes out the material so you can be pretty confident you sealed the end shut.

Another way I've sealed ends of cable sets is hot glue. Work some of that in the wiring and then heat it while also heat shrinking the external tubing. Again, stuff squeezes out and done correctly you have a fairly trustworthy seal. Still not Canon-Military spec connector worthy, but probably nice for an 818 project.

Both the above - you want to know your wiring is good beforehand because taking these apart to make changes is a mess.

I don't know of a material like this but in my Navy days we had "monkey-sh#t". It was thick brown goo that we packed into cabling going through bulkhead conduit to make water/fire resistant seals. Something that could be cleaned away with solvent for a removal/repair. Something like this could be worked into the end and shrink wrapped down, but easier to clean up if a tear down was needed.

In my "jack of all trades" activities, I recently replaced about $5,000 worth of "robotic grade" control cable-wire sets on a granite bridge saw (cuts 5' x 10' slabs of counter-top granite). Water flies everywhere when this is going on (saw is water cooled). The entire room is probably at 75% humidy 24-7. Deep inside the old cable sets, anywhere I cut them open along many feet of length, the wire sheaths were damp, the copper strands were corroded. This had to have either soaked through the sheath's or more likely creeped through from the ends by capillary action, etc. So long term soaking of harness and insulation in water, while insulation dependent of course, is just not good and will eventually ruin the subject. This machine was 8 years old at the time these cables were shot.

[Scargo]

This epoxy was mentioned by Bob in Cin... I believe. http://www.rbracing-rsr.com/download...t125_epoxy.pdf

I am with you that the ends must be well-sealed if you want the bundle to stay dry. I was thinking of using Permatex Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker for sealing open ends (and then shrink before it sets). Many silicones are good for up to 400°F. This does not prevent wire ends and crimps from wicking liquids though they could be pookied too.

[iWire]

I was thinking in terms of using something like either 3/4" Raychem DR 25 @ $4.5/ft. or cheap out with 5/8" non-shrinking, black, PVC @.$1.72/ft. for my main wire bundles.
I want to get the benefit of more water and chemical resistance for my wires. I see the possibility of the interior getting wet or oil or gas getting on wiring... Is there a downside to this approach? I don't see anyone doing this.

The reason that most people won't end up using Raychem is cost, complexity, and honestly it's overkill for this application. You will likely need 1in (very expensive per foot) for some of your larger bundles along with "Y" and "T" boots if you want to properly transition any branches. Those start at $20 per boot depending on the size and shape. In addition, from a practical standpoint building an entire harness as potentially complex (depending on the options you go with) is extremely difficult to run through closed conduit like Raychem. It requires a ton of pre-planning and being certain you have covered all your bases. Unless you've done a lot of this type of work, it's highly unlikely that it'll be perfect on the first run and the logistics of fixing it at that point are going to be a nightmare.

The split sleeve options people have posted are fantastic. They are simple to use and if you plan ahead enough you can shrink tube the ends for a really nice end result. Remember that if you are using good wire (like TXL - once again Raychem is overkill) it's jacketed with materials that are heat and chemical resistant. If you add in the protection from the braided sleeve it's more than enough for most of what you can throw at it. If you plan on tossing acid on it or lighting it on fire, none of those are going to help you anyway.

[Scargo]

I am surprised with your Debbie Downer attitude and comments, even if they are well-meaning and not self-serving. People spend their money in lots of unfathomable ways. Some want bling-bling oil filler caps. Some want all AN fittings and SS braided hoses. Some want to build a custom kit car. I agree that what I want is not needed in a street car.

Why is it that professional racing teams use all the high-end systems? Are we to be criticised because we want our "R" club level race cars to be lighter and more reliable? So what if we spend a few hundred more on wiring rather than a fancy livery. I want my wiring light, small and very reliable. Better, silver plated wire will carry more current and thus it can be downsized and be lighter. Better layouts and better distribution can make wiring runs shorter and cut loss.
And, yes, exactly, "it's jacketed with materials that are heat and chemical resistant." In the engine bay the better sleevings and PTFE insulations will take the heat better. I've had stock wire insulation and sleeving burn in the engine bay, whereas PTFE insulation would have survived.
And, regarding acid: PTFE would stand up to it.
PTFE would keep out moisture better. Things will get wet if you race in the rain or wash it due to an off track excursion or leak.
PTFE will not get hard or brittle.

[aquillen]

I agree with liking the Permatex Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker. Trust it for any number of things - even making resilient gun stock butt pad assemblies. For those using split sleeve (and I've used a fair amount of it in a number of projects, mostly non-auto) - arrange it as much as possible so the split is facing downward. 0) pretty much an obvious thing to do 1) looks better and hides wires better where it might not be closed 100% 2) helps drain any liquids that do get inside. Using a higher quality insulation certainly tends toward having a tough/impervious wiring. But if nothing else, sleeving it to keep it clean just makes sense to me. Especially after having torn down things to find yuk inside that makes working with the wiring you just exposed more hassle...

I do like to use the internal hot melt heat shrink on terminal crimps whenever I can get them to fit - not always an option, but where used they make a decent seal and such.

[Zach34]

If you do use that stuff, I think the aesthetics would be your main benefit - just make it look nice. None of our harnesses are going to see a lot of water, certainly not as much as the OEM ones do in the WRX's. As far as oil/chemicals - if you're getting enough oil/chemicals on your wires to cause concern, you probably have much bigger problems to deal with.

The PVC tube does make for a very nice-looking harness (also easy to clean), especially when sealed with heat-shrink on the ends, but it's harder than you'd think to thread the wires through that stuff, unless you're using all-new wire and pulling it through before cutting it to length.

[iWire]

I am surprised with your Debbie Downer attitude and comments, even if they are well-meaning and not self-serving. People spend their money in lots of unfathomable ways. Some want bling-bling oil filler caps. Some want all AN fittings and SS braided hoses. Some want to build a custom kit car. I agree that what I want is not needed in a street car.

Why is it that professional racing teams use all the high-end systems? Are we to be criticised because we want our "R" club level race cars to be lighter and more reliable? So what if we spend a few hundred more on wiring rather than a fancy livery. I want my wiring light, small and very reliable. Better, silver plated wire will carry more current and thus it can be downsized and be lighter. Better layouts and better distribution can make wiring runs shorter and cut loss.
And, yes, exactly, "it's jacketed with materials that are heat and chemical resistant." In the engine bay the better sleevings and PTFE insulations will take the heat better. I've had stock wire insulation and sleeving burn in the engine bay, whereas PTFE insulation would have survived.
And, regarding acid: PTFE would stand up to it.
PTFE would keep out moisture better. Things will get wet if you race in the rain or wash it due to an off track excursion or leak.
PTFE will not get hard or brittle.

My apologies that it came off that way, it was not the intent. You are 100% right that those materials are better and can stand up to tougher conditions and that's why we love them. I was simply answering the question as to why people haven't done it and I thought I gave a reasonable answer. I'm all for bling parts, so if anyone wants to go that route, more power to them. We come from a standpoint of getting the most for your dollar and the things people described in this thread fit that bill. To us, it is subjective that the gains that may come from using the highest grade materials are worth the expense. We're not shooting rockets into space, flying aircraft, or staying under water for weeks at a time.

Why do professional race teams use all the high-end systems? Because their lively-hood quite simply depends on the difference in milliseconds so they will do anything they can to get an edge. For a weekend warrior/fun car, the money saved by using still excellent materials but don't come with a premium price tag means more money for tires and race fuel.

I'm not here to get into argument, just voicing an opinion based on our experiences.

[DrunkenSailor]

I want my wiring light, small and very reliable. Better, silver plated wire will carry more current and thus it can be downsized and be lighter.

Just to be clear, Silver plating will not carry more current, and can not be a smaller gauge than bare copper. At higher temperatures, silver is often used to minimize oxidation in spite of its high cost. Silver is also used for high-frequency applications where silver’s excellent electrical conductivity and the skin effect work together to reduce impedance and attenuation. (Skin effect is an electrical phenomenon in which current tends to flow on the outer surface of a conductor.) Silver will corrode and tarnish, just as copper, but its conductivity is maintained through the tarnishing. Silver does have 106% of the conductivity of copper, but this will not increase the ampacity. Silver plating is also good in high temperature environments, 150C-200C.

[Scargo]

OK, silver plating is not relevant to ampacity, but wire types that often use silver plated copper tend to have better insulators. As you say, silver is better in certain environments and oxidation doesn't affect conductivity. Copper is great till it starts oxidizing. The connections are where it will break down whereas silver will not cause the joint to oxidize to the point where it gets into the cycle of heat and oxidation and eventually fail.
When using mil-spec wires like 44 and 55, with single or double layers of insulators, you can allow the wires to get hotter or carry more amps. So, it's not just the silver plate, which is better than tin, but the quality of the insulation and how it can better hold up in a hot environment. The skin effect is pretty meaningless in a car application.
I would think that 24 or 26 gauge could be used for sensor or signal wiring. I don't think TXL comes smaller than 22 gauge. I could see a 30% decrease in bundle size by using PTFE insulated wire over TXL or TXE. OTOH, I don't claim to know what you can get away with in the real world since I used almost no mil-spec wire in a car.

[DrunkenSailor]

Copper is great till it starts oxidizing. The connections are where it will break down

Totally agree, exposed copper and the environment do not play nice.

with single or double layers of insulators, you can allow the wires to get hotter or carry more amps.

Not exactly true. The wires can get hotter, in terms of temperature, dependant on the insulation, not hotter in terms of amperage. The NEC, IEC, NFPA, and IEEE have set the standards for wire ampacity based on environmental concerns and the failure point of the copper. A 22ga wire is rated for no more than 7 Amps for chassis wiring, and no more than 0.92 Amps for power distribution, regardless of the insulation. The insulation protects the wire from the environment, not the environment from the conductor. The copper will fail at the same point every time. As more wires are bundled together, this rating goes down. NEC table 310.15(B)(3)(a) sets this standard. If there are 4-6 conductors, the amperage rating is 80% of that of a single conductor. When you get to 10-20 conductors bundled together, the rating is 50% of a single conductor.

I would think that 24 or 26 gauge could be used for sensor or signal wiring

In sizing wire for an application, the total run length of the circuit must be considered also. Again to use 22ga wire, if the circuit runs from the front of the car, to the back, lets say 10’, the total circuit is therefore 20’, the voltage drop over that length is close to 4 volts, resulting in an 8 volt circuit, so the conductor size must be increased to compensate for the voltage drop.

I could see a 30% decrease in bundle size by using PTFE insulated wire over TXL or TXE.

Agreed, I constantly look for the smallest allowable OD for military and other applications where it is critical. In the automotive world mPPE is also quickly becoming popular. The Toyota Tocoma is completely wired with mPPE. It has the same OD as PTFE, but has tin plated conductors instead of the silver plated of PTFE.

[Scargo]

Dear Drunken Sailor,
Why should I believe a drunken sailor? Probably an old drunken sailor, to boot...
It is spooky that I feel like you have literally been looking over my shoulder as I read about wiring, based on your comments. Some of it I know and some of your comments were a good refresher or new knowledge.
I appreciate the input. It helps solidify and expand on what I know.
I have had questions. You have answered some of them; like what is a wire run length? You say it is going and coming combined. That helps with doing accurate calculations.
How do you feel about tin plated wire and tin plated connectors with their increase in resistance? How does this compare to having ten feet less wire? Am I splitting hairs when considering wire size and coating when looking at runs of three to ten feet?
For a sensor that is handling five volts and next to no amperage, what size is adequate for a three to ten foot run?
Seems some recommend shielded pairs for some inputs and for others it seems that the ECU's are fairly insensitive to noise in the signal.
So many questions...

[UnhipPopano]

As long as this conversation has gone down a rabbit hole:

Scargo, Do not forget about Can Bus networking impedance and noise questions.

Drunken Sailor, Most of what you identify is only good if you are performing calculations on an existing design, to verify that the chosen wire is adequate for each of the runs. by this, we are talking about the minimum wire size. For durability, the wire size used should be at least one size larger than the minimum.

Now, none of this has much to do with wire harness sheathing, unless we start talking about thermal heat transfer calculations.

[Scargo]

As long as this conversation has gone down a rabbit hole:

Scargo, Do not forget about Can Bus networking impedance and noise questions.

Drunken Sailor, Most of what you identify is only good if you are performing calculations on an existing design, to verify that the chosen wire is adequate for each of the runs. by this, we are talking about the minimum wire size. For durability, the wire size used should be at least one size larger than the minimum.

Now, none of this has much to do with wire harness sheathing, unless we start talking about thermal heat transfer calculations.

Now, I can't tell whether you are pulling my leg or not.
I'm all for taking it to the street. Might be like a Trump and Biden brawl. Instead, what about we take the broader discussion of the wiring to this DIY Wiring thread which is already started? Then we can talk more generally about all things related to wiring an 818...

Just seemed like this sheathing topic was pooping out and needed invigorating! Seriously, it is my fault for getting off topic, except for, like you mentioned the sheathing can be a factor in heat/loss calculations. If we can agree on loads then we can look at various sheathings and sizes of bundles or multiple routings, if all that exercise is really meaningful. For us racers, it might be. I can't say I'm good at crunching numbers in this regard. Some things don't seem to be well-defined enough to get to the hair-splitting phase. Perhaps we can do a little more defining on the other thread?