Will reducing wire size after a long run drop my voltage?

[VoodooCLD]

I'm wiring up an ARB 63 quart fridge in my 2018 GMC Sierra. I've already set up a dual battery system in the engine compartment with a blue sea ACR and fuse block.
Since i'll have about a 20 foot run from the second battery to where the fridge is going to be, i opted for 8 gauge OFC wire. I plan to install a couple different DC port in the bed. My main concern is to get as much voltage to the fridge port as possible. I was originally planning on installing a 1/4" slide on terminal to the 8 gauge wire and then tapping off of that port to run power to a USB and cigarette outlet. However it seems no one sells 1/4" blade terminals for 8 awg wire.

My question is, if i trim a few strand off of the 8awg wire so i can fit it into a 10 awg blade terminal, will that reduce my voltage at the fridge connector? Or will i still be seeing max available voltage that the 8 awg will allow?

 

[dwh]

No problem. The extra mass of the metal that wraps around and gets crimped will make up for 1/4" of a few missing copper strands.

Going from #8 down to #14 halfway though a 40' loop would be a problem...depending on the load. (Voltage drop always varies based on load.)

 

[john61ct]

Use the heavier gauge wire for the run to prevent V drop.

A short bit if lighter gauge to fit the terminal is NP as long of course as it's heavy enough from the heat-safety POV.

asymmetric butt connectors are best

 

[VoodooCLD]

I don't understand well enough how the electricity flows through the wire. Part of me feels like those few strands that i cut off aren't helping carry any electricity, which makes me think i should use some sort of reducer to help make those strands effective all the way to where i step down. If so, where can i get these asymmetric butt connectors?

Or is that incorrect thinking, and the extra wires in the pack help prevent voltage drop even though they aren't connected to anything on the end?

 

[DaveInDenver]

where can i get these asymmetric butt connectors?

I like solder sleeves for making splices and they are designed to accommodate various numbers and sizes of wires. But you can mimic the real ones using various crimps and shrink sleeve.

http://www.te.com/usa-en/plp/soldersleeve-shield-terminators/Y30AG.html

 

[john61ct]

For wiring supplies both Ancor and FTZ are good brands, marine quality.

FTZ Crimp 'N Seal includes the waterproof Heat Shrink

Step-Down Butt Splice is their term for these.

Dozens of great suppliers out there, Defender, Jamestown, Fisheries supply. . .

 

[dwh]

I don't understand well enough how the electricity flows through the wire. Part of me feels like those few strands that i cut off aren't helping carry any electricity, which makes me think i should use some sort of reducer to help make those strands effective all the way to where i step down. If so, where can i get these asymmetric butt connectors?

Or is that incorrect thinking, and the extra wires in the pack help prevent voltage drop even though they aren't connected to anything on the end?

Yea, no. It's not water.

Some of the energy flows through the copper, some flows around the copper as a field. Plus, all the strands are touching inside the insulating sheathing.

So if you cut the tips off of say 10% of the strands, you are not increasing the voltage drop by 10%. The total resistance value of the entire circuit is what matters. By cutting off 10% of the strands 1/4" from the end you increase the resistance of the entire circuit by only a miniscule amount. Like 0.001% or something stupid like that.

But as I said, you are also replacing the missing copper with a different conductive material, so now that 0.001% becomes 0.0000001% or whatever (someone else can do the math if they want, I'm not going to bother).


Voltage drop is a variable relationship between voltage, resistance and load. It's not nearly as simple as Internet voltage drop calculators make it out to be. It's also not nearly as important as Internet gurus make it out to be.

You are already oversize on the wire, shaving a hair off isn't going to make a noticable difference.

What is FAR more important is to make sure you do the crimps correctly. There is definitely a right way and a wong way for every kind of connector.

Do it the wrong way and you could add more resistance than cutting the tips off a few strands of wire.

 

[brianjwilson]

FYI blue sea sells heat shrink, crimp connectors that are “asymmetrical”. Not cheap but they’re sure handy in splitting circuits or stepping down wire size etc. It may not make a big difference but it does feel nice getting all of the strands of wire in the connectors at least!

 

[vintageracer]

I have read and now cannot find the articles discussing wire splicing and wire connections in "Off-Road" and
"Trailer" applications. These "Pro's" possibly self anointed recommend "Crimp" connectors for use in these applications rather than soldered connections due to vibration, moisture and other issues associated with this type of environment. The electrical theory is that "Crimp" connections are a more solid connection in high vibration situations that a soldered connection.

All recommended good quality "Crimp" connectors with Heat Shrink a part of the connector or added if not a part of the "Crimp" connector.

Everyone's thoughts?

 

[DaveInDenver]

My opinion is you want to either crimp or solder but not both. If you look at a high reliability applications you'll see both techniques used in places. My experience is in aerospace & spacecraft. The company where I worked would exclusive crimp terminals with one exception, Tyco solder sleeves like I linked to earlier carry an AS-83519 qualification to attach ground leads to cable shields. But I've seen the solder sleeves used for general purpose splices on non-power cables (e.g. data) other places, even in harsh environments like aircraft engines.

One of the reasons crimping is preferred is consistency. You can calibrate the tool and have a high confidence that it's repeatable.

With soldering there's more risk since it's a manual operation and relies on workmanship and inspection more. Did the tech use the right flux, too much or too little solder, etc. If solder wicks up the cable it loses flexibility, which creates a potential stress in the future. That's part of the reason the solder sleeves exist, it's a fixed amount of solder inside the ring so the operation is consistent and it's got a temp sensitive plastic that changes when you've held it in front of the heat gun long enough.

Electrically there's no significant difference. A properly crimped terminal will cold work into a homogeneous connection, so cut you wouldn't see any voids just as if it was soldered.

 

[DaveInDenver]

My question is, if i trim a few strand off of the 8awg wire so i can fit it into a 10 awg blade terminal, will that reduce my voltage at the fridge connector? Or will i still be seeing max available voltage that the 8 awg will allow?

Cutting a few strands isn't going to impact the cable's voltage drop. The resistance is the same over 99.99% of the cable that is intact and you nicking a few wires at the end isn't going to change that. But it does change the cable's current carrying capacity. The necked down section is what the whole cable can now carry. It's in-effect a fuse or fusible link. Whether that ever becomes a problem, well, it's probably unlikely in the real world.

 

[john61ct]

Crimp is a normal word, no need for quotes.

An expert solderer can do as good a job, but takes a lot of knowledge and practice.

Crimping relies on expensive equipment, but once set up properly even a noob can get excellent **repeatable** terminations.

A proper crimp gains nothing from adding solder.

Yes adhesive-lined heatshrink is great, part of the fitting or as an add-on.

 

[FlipperFla]

I'm wiring up an ARB 63 quart fridge in my 2018 GMC Sierra. I've already set up a dual battery system in the engine compartment with a blue sea ACR and fuse block.
Since i'll have about a 20 foot run from the second battery to where the fridge is going to be, i opted for 8 gauge OFC wire. I plan to install a couple different DC port in the bed. My main concern is to get as much voltage to the fridge port as possible. I was originally planning on installing a 1/4" slide on terminal to the 8 gauge wire and then tapping off of that port to run power to a USB and cigarette outlet. However it seems no one sells 1/4" blade terminals for 8 awg wire.

My question is, if i trim a few strand off of the 8awg wire so i can fit it into a 10 awg blade terminal, will that reduce my voltage at the fridge connector? Or will i still be seeing max available voltage that the 8 awg will allow?

Do a google search “wire gauge chart” this will tell you what size wire to run with factors of length of run and current (amps) I usually go up one gauge for a bullet proof factor you can find the chart on Blue Seas web site

 

[Superduty]

What gauge is the wire that will come off the plug on your ARB? 14 or 16 ga?

 

[FlipperFla]

Crimp is a normal word, no need for quotes.

An expert solderer can do as good a job, but takes a lot of knowledge and practice.

Crimping relies on expensive equipment, but once set up properly even a noob can get excellent **repeatable** terminations.

A proper crimp gains nothing from adding solder.

Yes adhesive-lined heatshrink is great, part of the fitting or as an add-on.

Check out this bad boy, Im retired now but I used to wire the big offshore fishing boats 30-40 footers with trips or quad engines. They would bring the boats right from the factory,while the mechanics would be mounting the engines I would be installing all the elecrtonics, usually 2-3 18” displays, radar, GPS, some with 3 VHF radios/ antennas, some of the AV systems cost more than my truck! one boat had 42 rocker switches across the center console. This was my go to tool for the big wiring they also use these for rigging sailboats. Not cheap but once crimped it was a done deal. It takes two hands to close it. If anybody needs some large cables crimped give me a shout.