# Best way to join two 8 gauge wires?



## ImK'ed (Aug 12, 2013)

As title whats best way to join two 8 gauge wires, one side goes to 100 amp fuse and other side is main car harness fuse box


----------



## MUGWUMP (Jan 29, 2012)

Let me say I'm not an expert, but what do you plan on powering from your fuse box? Is it's an amp? I've never heard of powering anything that requires 8g wire from the fuse box.

EDIT: To answer the question, I would divide each end of wire into two twisted ends and then twist them together and solder. Cover with shrink tube or electrical tape.


----------



## ImK'ed (Aug 12, 2013)

No its the standard car loom it powers the entire car and starter motor, the amp is fused seperately and the alternator is seperate, ive fitted a proper terminal so lost the stock 100amp fuse on the terminal so im using a maxi fuse holder with a 100 amp fuse, so i need to join the wire from car loom to fuse holder so just two wires both 8 gauge


----------



## minbari (Mar 3, 2011)

I would have used a standard mANL fuse holder for 1/0 or 4ga and just twisted them together. a 4ga opening should fit (2) 8ga just fine.


----------



## MUGWUMP (Jan 29, 2012)

I know they make butt connectors for 8g, but as long as you've insulated it proper I think twisting and soldering is fine. The idea with dividing the wire into two parts is it's not as much of a bulge and easier to twist. After you've twisted the pairs together bend one end towards the fuse and one towards the harness and insulate(shrink tube/electrical tape).

EDIT: or what he said. I just got done with a 12 hour shift. Didn't understand exactly what u were doing :/


----------



## Jepalan (Jun 27, 2013)

I prefer to do an inline twist and solder. For an 8 awg power wire I use the heavy walled heatshrink with glue lining, or I use a wrap or two of rubber splicing tape, then Scotch wide temp electrical tape over that. Sometimes I use liquid tape instead of rubber splice tape.

If using a crimp splice (esp for large awg wires), I still like to wick solder into the connection and seal as above.


----------



## ImK'ed (Aug 12, 2013)

I like inline twist, thats exactly what i need to do, how did you twist it like that?


----------



## minbari (Mar 3, 2011)

it looks like 18ga wire, it not hard to twist wire that small. try twisting (2) 8ga wires like that and soldering. will be a melted mess.


----------



## Jepalan (Jun 27, 2013)

minbari said:


> it looks like 18ga wire, it not hard to twist wire that small. try twisting (2) 8ga wires like that and soldering. will be a melted mess.


Yeah, it won't look like that pic, but can be done with 8 awg if you strip enough wire. You can also just tin and lay the wires side by side and solder, but I don't like relying only on the solder for the mechanical connection. 

You can also push the strands into one another, slightly twist and then solder. 

There are a ton of good splice kits for large gauge wire. Good crimp splices work in a pinch (groan).

I do prefer a water proof splice for power wire - then I don't have to worry about corrosion setting in.


----------



## ImK'ed (Aug 12, 2013)

I'll try pushing them into eachother see what happens


----------



## Jepalan (Jun 27, 2013)

Here is the "intermingle" method...


----------



## qwertydude (Dec 22, 2008)

Cut half of the wires away then fan them out flat, then twist them together and solder. This makes an excellent mechanical and electrical connection without a giant bulge in the wire.


----------



## copperears (Sep 2, 2010)

Keep in mind, the National Electrical Code specifies that splices are not to be made using solder only. Use a heavy wall butt splice or other pressure type connector. If you want to flow some solder into the ends after to minimize oxidization, feel free.


----------



## qwertydude (Dec 22, 2008)

Keep in mind this is in a car and not in a home. National electrical code allows for the use of wire nuts but you don't see people wire nutting their speaker wires to extend them.

In a high vibration environment and a joint that will experience more flex a pressure connector will eventually break the individual strands due to fatigue. A proper solder job in this case puts more strain relief than the average butt connector and will also present a cleaner look and if needed easier installation should the need to pull the wire through holes arises.


----------



## ImK'ed (Aug 12, 2013)

Qwertydude, can you explain in a bit more detail ? Its morning here and i had a **** night, my maxi fuse holder has 100 amp fuse in it so the connection must withstand that. The fuse holder side has high multi strand cable very flexible and the car loom side is the standard battery lead stiff wire lower strand count, both 8 gauge, i tried the intermingle method last night and made a mess lol


----------



## minbari (Mar 3, 2011)

qwertydude said:


> Keep in mind this is in a car and not in a home. National electrical code allows for the use of wire nuts but you don't see people wire nutting their speaker wires to extend them.
> 
> *In a high vibration environment and a joint that will experience more flex a pressure connector will eventually break the individual strands due to fatigue.* A proper solder job in this case puts more strain relief than the average butt connector and will also present a cleaner look and if needed easier installation should the need to pull the wire through holes arises.


not sure I agree with that. every pin and high gauge wire in my car, from the factory, is crimped.


----------



## 94VG30DE (Nov 28, 2007)

Let's not let this devolve into another "crimp vs solder" debate, there are too many already. 
OEMs have proper crimp tools to ensure exact pressure on the joint, and in the automotive environment, the "perfect" crimp is absolutely better. The problem is in practice, the perfect crimp is easy to screw up without the right tool/die setup. That's why so many people advocate solder or a combo of both. 

Personally, with 8 ga wire, I would get a good heavy butt connector, crimp that, then flow solder into the ends until nothing more would go in. Then I would cover the whole thing in a good adhesive-lined heat shrink, and constrain the cable to something else to minimize vibration.


----------



## ImK'ed (Aug 12, 2013)

I would happily crimp a butt connector but cant find one this size!!


----------



## 94VG30DE (Nov 28, 2007)

Here in the states, I would go to NAPA (or any auto repair parts stores, especially ones that cater to shops) or a Home Depot/Lowes. I'm not sure what you have in the UK. 
Look in the "battery replacement/repair" section of the auto parts store, and they should have battery cables, and 8ga butt connectors.


----------



## qwertydude (Dec 22, 2008)

94VG30DE said:


> Let's not let this devolve into another "crimp vs solder" debate, there are too many already.
> OEMs have proper crimp tools to ensure exact pressure on the joint, and in the automotive environment, the "perfect" crimp is absolutely better. The problem is in practice, the perfect crimp is easy to screw up without the right tool/die setup. That's why so many people advocate solder or a combo of both.
> 
> Personally, with 8 ga wire, I would get a good heavy butt connector, crimp that, then flow solder into the ends until nothing more would go in. Then I would cover the whole thing in a good adhesive-lined heat shrink, and constrain the cable to something else to minimize vibration.


I wholeheartedly agree with that. I used to work in avionics. The crimpers we used were FAA certified and cost about $1000 a piece they had anvils specifically made for a certain gauge and whether it was solid core or stranded. They distributed the crimp forces perfectly so that the strain relief on the ends of the wires wouldn't force vibrations to break the strands while at the same time putting enough force to pressure weld the two components into an electrically ideal connection. Automotive crimp connectors use a similar though not as stringently enforced standard as the FAA.

Your standard $5 crimpers will positively destroy wires and make a terrible electrical connection since they only pinch wires from the outside and not make an actual full length pressure welded crimp in which case a half decent soldering job would definitely be better.


----------



## sirbOOm (Jan 24, 2013)

Join with a MANL fuse and holder. Done.


----------



## ImK'ed (Aug 12, 2013)

Done it with intermingle method not best looking but quite solid, i intermingle the wires then tied them with copper strands and the soldered it it wasnt fully covered in solder but it was rock hard, then taped it up and put two split looms over it, then it goes to 100 amp maxi fuse and then 8 gauge to terminal , i hope this 8 gauge can handle upto 100 amps its only max 8-9 inches including holder


----------



## qwertydude (Dec 22, 2008)

It's only 8-9 inches to the amp? 8 gauge is only good for about 50 amps for the average length run to an amplifier. More current than that and it'll drop too much voltage to be acceptable.


----------



## 94VG30DE (Nov 28, 2007)

ImK'ed said:


> it wasnt fully covered in solder


... this doesn't sound good...


----------



## ImK'ed (Aug 12, 2013)

Its only 8-9 inches to the car loom where original fuse was, it soaket alot of solder one side is completely covered but the other side is kinda civered it was burning too much insulation so left it at that plus it had wicked at both ends


----------



## ecbmxer (Dec 1, 2010)

There are some connectors with allen key set screws you can use to connect larger gauge wire like that. I used to have one in a previous install when I had to move my amp and needed extra length. Never had an issue. Just shrink wrap the connector since they're usually bare metal.


----------



## ImK'ed (Aug 12, 2013)

One thing ive been thinking is the fuse is there to protect the wire from battery to fuse box, soon as it gets into fuse box it has a 100 amp fuse, i was thinking if i upgraded that wiring to 4 gauge will my car dim less? Even though the amps are going direct to battery but will the thicker gauge help? Also i now feel like the 8 gauge maxi holder wiring maybe is too thin even though the standard car loom was 8 gauge?


----------



## Jepalan (Jun 27, 2013)

ImK'ed said:


> One thing ive been thinking is the fuse is there to protect the wire from battery to fuse box, soon as it gets into fuse box it has a 100 amp fuse, i was thinking if i upgraded that wiring to 4 gauge will my car dim less? Even though the amps are going direct to battery but will the thicker gauge help? Also i now feel like the 8 gauge maxi holder wiring maybe is too thin even though the standard car loom was 8 gauge?


??????? What standard car loom has 8 AWG wire? ??????? 18 or 16 maybe. But 8?


----------



## qwertydude (Dec 22, 2008)

ImK'ed said:


> One thing ive been thinking is the fuse is there to protect the wire from battery to fuse box, soon as it gets into fuse box it has a 100 amp fuse, i was thinking if i upgraded that wiring to 4 gauge will my car dim less? Even though the amps are going direct to battery but will the thicker gauge help? Also i now feel like the 8 gauge maxi holder wiring maybe is too thin even though the standard car loom was 8 gauge?


Surprisingly upgrading the power connection to your amps will likely result in more dimming. It means your amps will be able to draw even more current since voltage isn't dropping in the wires. Amps drawing more current means lights dim more. If your lights are dimming the only solution is the big three and a better battery. 

Controversially you can try putting a huge ultracap like my 7S 2600 farad unit. I still haven't had a chance to fully build mine into my system, a Ford Focus with a stock electrical system and an AGM battery. I did temporarily connect it and my lights definitely don't dim on the highest bass peaks where my amp will pull 120 amps of current but they can cause quite some problems themselves if not connected properly.

For example right now they'll blow the inline fuse when I try to start the car soon after shutting off since they're maintaining 14.4 volts and will send nearly all the starting current through the amp power wire which blows the fuse.


----------



## ImK'ed (Aug 12, 2013)

My car is civic type r 2009 fn2, it has 8 gauge from under hood fuse box to battery and originaly it had a 100 amp fuse directly on terminal but this has been removed because im using a proper battery terminal, so to put a fuse inline i put a 100 amp maxi, but from batt to fuse box is only approx 17-18 inches and fuse box itself is internally protected im sure


----------



## 94VG30DE (Nov 28, 2007)

qwertydude said:


> *Surprisingly upgrading the power connection to your amps will likely result in more dimming. It means your amps will be able to draw even more current since voltage isn't dropping in the wires.* Amps drawing more current means lights dim more. If your lights are dimming the only solution is the big three and a better battery.


This is just not how electricity works. 
First sentence you recommend not upgrading wiring to keep the lights from dimming, second sentence you recommend the opposite. 
Increased wire gauge decreases the charging demands (current and voltage) of the system. Whether it is enough to fix whatever is causing your lights to dim is a separate discussion.


----------



## ImK'ed (Aug 12, 2013)

So is it worth me upgrading stock fuse box wiring? And should i put a 100!amp fuse inline even though its 18 inches from batt to fuse box? Im not happy with the 8 gauge join and rather upgrade the wire to 4 gauge and maybe a mini anl holder next to terminal? Im not sure if in the us you guys have a terminal fuse on the 8th gen civics


----------



## copperears (Sep 2, 2010)

> Surprisingly upgrading the power connection to your amps will likely result in more dimming. It means your amps will be able to draw even more current since voltage isn't dropping in the wires. Amps drawing more current means lights dim more. If your lights are dimming the only solution is the big three and a better battery.


Nope, the amp rails will get what they are asking for and the power won't be dissapated in the smaller wire as heat and voltage drop.


----------



## qwertydude (Dec 22, 2008)

94VG30DE said:


> This is just not how electricity works.
> First sentence you recommend not upgrading wiring to keep the lights from dimming, second sentence you recommend the opposite.
> Increased wire gauge decreases the charging demands (current and voltage) of the system. Whether it is enough to fix whatever is causing your lights to dim is a separate discussion.


I never said don't upgrade the wiring, read it very carefully especially the last sentence of the first paragraph. " If your lights are dimming the only solution is the big three and a better battery."

Get the proper wiring in the first place to prevent voltage dropping from harming your amps but upgrading the wiring from battery to amp WILL DO NOTHING, ABSOLUTLEY NOTHING for dimming. Ohms law doesn't magically disappear because your amplifiers are happy. If your amplifiers now can draw more power out of your system because of upgraded wiring but you still have a poor electrical system that will only make dimming worse. But I never said don't put the proper wiring in the first place. That is putting words in my mouth.


----------



## qwertydude (Dec 22, 2008)

copperears said:


> Nope, the amp rails will get what they are asking for and the power won't be dissapated in the smaller wire as heat and voltage drop.


The amp rails will only get what they're asking for if you have wire of sufficient size to let them draw their power.

Most amps are unregulated and so if voltage is dropping because of poor wiring the amps won't draw as much current. Put your amps on a bench tester and power supply. You'll readily see this. This is why most people never truly get what their amps are rated for since they're rated at 14.4 volts usually.

Drop this to 13 volts, then drop it to 11 volts. Measure the actual used current and you'll see on unregulated amplifiers the actual amps they use drops almost proportionally.

A 100 amp draw on 14.4 volts will draw only about 90 amps on 13 volts and only about 76 amps on 11 volts. Below that then you might start having problems with power supply instability causing excess heat build up.

But it still holds true in the real world. If your wiring is dropping voltage your amps will not pull their maximum current. But you still shouldn't be using it to limit your amplifiers output anyways.

The point I'm trying to make though is upgrading the power wire from battery to amp will not help dimming whatsoever.


----------



## copperears (Sep 2, 2010)

> The point I'm trying to make though is upgrading the power wire from battery to amp will not help dimming whatsoever.



If all your power is going to the amplifier by using a bigger wire, you will be able to turn the volume down. By not losing available power to parasitic losses you might have enough power to satisify your preferred volume level.

I just don't believe a bigger sized wire will make the problem worse.


----------



## qwertydude (Dec 22, 2008)

A bigger wire won't make the problem worse except if the current wire is undersized and dropping voltage AND on top of that is currently dimming the lights. Then it most certainly will make dimming worse as a bigger wire will allow the amps to draw even more power.

The added voltage drop from higher current then moves from the power wire to the battery and alternator dimming the lights worse.


----------



## copperears (Sep 2, 2010)

You missed my point about the volume.


----------



## turbo5upra (Oct 3, 2008)

Most amps are unregulated? I think that was true 10+ years ago...


----------



## qwertydude (Dec 22, 2008)

turbo5upra said:


> Most amps are unregulated? I think that was true 10+ years ago...


Yes most amps are unregulated. It's one of the reasons the CEA performance standard citing power at a certain voltage was created so that people can get an idea of what true amplifier's wattage is. Generally the regulated amps even nowadays are still in the more expensive range of amps. And it makes such a minor difference in everyday performance most manufacturers don't bother to put regulation in their amps.

http://www.diymobileaudio.com/forum...sion/98096-regulated-vs-unregulated-amps.html


----------



## minbari (Mar 3, 2011)

qwertydude said:


> Yes most amps are unregulated. It's one of the reasons the CEA performance standard citing power at a certain voltage was created so that people can get an idea of what true amplifier's wattage is. Generally the regulated amps even nowadays are still in the more expensive range of amps. And it makes such a minor difference in everyday performance most manufacturers don't bother to put regulation in their amps.
> 
> http://www.diymobileaudio.com/forum...sion/98096-regulated-vs-unregulated-amps.html


Yup


If an amplifier states different wattage at 12v vs 14.4v, then it is unregulated. A regulated amp wouldnt vary

sent from my phone using digital farts


----------



## turbo5upra (Oct 3, 2008)

different degrees of regulating- doesn't mean its completely unregulated.


----------



## copperears (Sep 2, 2010)

> Yes most amps are unregulated. It's one of the reasons the CEA performance standard citing power at a certain voltage was created so that people can get an idea of what true amplifier's wattage is. Generally the regulated amps even nowadays are still in the more expensive range of amps. And it makes such a minor difference in everyday performance most manufacturers don't bother to put regulation in their amps.


I've bought 7 amplifiers in the past 10 years, all seem to be regulated, even my cheaper Powerbass ones. From the time I turn my key off until the system shuts down at about 10.9v the volume doesn't change.


----------



## minbari (Mar 3, 2011)

That is not really how it works, unless you are near maxed out.
At normal listening levels, the power supply can still put out 25 watts/ch even with lower input voltage 

It could be that you have had regulated amps too, but doesn't mean you have by that test. 

sent from my phone using digital farts


----------



## The Performer (Aug 12, 2012)

For the love of God you guys arguing over what's best solution for this guy are all handicapped... 

To the op, get yourself an 8 gauge seamless butt connector then take a razor knife and cut the insulator off, crimp it on to the wires, heat it with a torch, flow solder into it then cover it with two layers of heat shrink. Call that **** a day already... 

Sent from my SCH-I545 using Tapatalk 2


----------



## ImK'ed (Aug 12, 2013)

To the performer, im done replaced it all with straight 4 gauge!


----------



## qwertydude (Dec 22, 2008)

copperears said:


> I've bought 7 amplifiers in the past 10 years, all seem to be regulated, even my cheaper Powerbass ones. From the time I turn my key off until the system shuts down at about 10.9v the volume doesn't change.


Have you tested them with a bench tester? I have. All my Pioneers, Sony's and Kenwoods were unregulated. Even though you can't hear the volume change doesn't mean it's regulated.

Most people can't hear a gradual increase or decrease in volume of less than a db. It's very subtle. And since it takes doubling in wattage to make a 3 db change in volume, you're not going to hear a distinct change when the power changes 15-20% even. Plus like was said before you definitely won't hear it unless you're maxing out the amplifier and then hit distortion when the voltage drops.


----------

