connecting multiple wires?

[Daniel the Texan]

Hi all,

I am rewiring my trailer lights and was wondering what people use to connect multiple (3 or more) wires. Mine has all those blue scotch locks to tap into wires, but I heard those are not very reliable. Twist locks, butt connectors, special techniques? Thanks.

[John in Michigan]

I use crimp splice connectors for all 12vdc wire splices. For exterior wire splices such as brake wire splices, I use weatherproof crimp splice connectors. My 1978 Trillium 4500 has all the original crimp splices and none have failed.

[steve dunham]

If you decide to use crimp connections buy good ones such as T&B or 3M . The plating on the metal crimp sleeves and the insulation is of much higher quality than the cheap Chinese connectors . Also use a genuine T&B indentor style crimper.
They cost about $30 but they perform much better than the $5 ones sold at HD. I still have my original T&B crimper from when I started the trade in the late 60's . Nothing more frustrating than trying to find a bad splice once everything is covered up.

[gordon2]

http://www.bestboatwire.com/3-way-wi...rink-16-14-awg

[Darwin Maring]

If you can not find the weatherproof ones, fill them with dielectris grease B 4 you crimp. It will keep the nasty stuff out.

Milspec - You only crimp once. Most people will crimp one more time and that weakens the first crimp.

I prefer the ratching crimp tool as it allows you to get the best crimp.
Ratcheting Crimping Tool

[David B.]

I strip away part of the insulation to splice into a wire, then solder, and wrap with electrical tape. If terminating several wires to the battery, first go through a fuse block, then only one fused wire goes to the battery.
For the multiple negative/ground wires I go to a buss block, then one wire to the battery.
Dave & Paula

[mary and bob]

junction box

[Carl V]

Depending on the wire size, these can accommodate 3 or 4 wires. Not weatherproof though.

To weatherproof a regular crimp connector, I slide a length of heat shrink over them, fill the ends with sealant like silicone, apply heat, the sealant will ooze out the ends and seal the connection.

[Terry G]

Originally Posted by David B.

I strip away part of the insulation to splice into a wire, then solder, and wrap with electrical tape. If terminating several wires to the battery, first go through a fuse block, then only one fused wire goes to the battery.
For the multiple negative/ground wires I go to a buss block, then one wire to the battery.
Dave & Paula

Some years ago, I used to work on radio, siren, and electrical systems in police cars and fire trucks. When they came into the shop with a problem, the majority of times it was a bad crimp. On my Casita, I go the solder route. The best electrical tape is the stuff that you stretch and then it fuses together in a watertight bond.

[Mike_L]

Solder is the best. Then a good quality electrical tape.

[larryf]

I don't use electrical tape if I have to and I only use 3M, if you want a water tight and strong connection the best is to solder the wires and use quality shrink tubeing. If you want high quality terminal connectors buy them from a heavy truck or equipment parts supplier generally they only handle the best.

[Casita Greg]

I really like these little connectors. They make them for joining 2 wires, and up to several wires which can be "ganged" together. The nice thing about these is they clamp the wire, they don't cut into the wire like Scotch-Locks do.

https://www.amazon.com/Wago-222-412-.../dp/B003K0J4IQ

[Triker]

I solder and use heat shrink tubing when possible. If using electrical tape, don't stretch the last wrap.

[Darwin Maring]

mary and bob
I retentively purchased a box like yours at a low price from Walmart on line site.

There were quite allot of excellent posts on this subject. You cant go wrong following the advice on these posts.

[steve dunham]

Originally Posted by Terry G

Some years ago, I used to work on radio, siren, and electrical systems in police cars and fire trucks. When they came into the shop with a problem, the majority of times it was a bad crimp. On my Casita, I go the solder route. The best electrical tape is the stuff that you stretch and then it fuses together in a watertight bond.

3M #23 is a self sealing / fusing cross link polymer tape. When stretched properly it changes colors and fuses it's self into one solid layer . It needs to be covered with a half lapped layer of 3M #33+ or #88 tape. The #23 tape is used to make high voltage stress cones and splices. . I have made many 13,800 VAC splices with it in manholes and even when the manhole filled with water the splices maintained their integrity . They also make a shrink tube for underground splices / connections . It is expensive but it really works well. The better grade / higher quality supplies are often only sold by electrical wholesale house or on the internet . A lot of the parts sold by HD are not the best available because they are selling to homeowners who are only looking for a low / cheap price.

[mary and bob]

Originally Posted by Darwin Maring

mary and bob
I retentively purchased a box like yours at a low price from Walmart on line site.

There were quite allot of excellent posts on this subject. You cant go wrong following the advice on these posts.

I got a couple on eBay. Have not been able to make it to be completely waterproof however. As a long time truck & trailer mechanic in the Northeast, we never found any type of connectors that lasted forever. Even the OEM molded plugs were subject to failure. Best bet is to make any connections where they can easily be accessed again.

[redbarron55]

Originally Posted by gordon2

3 Way Wire Splice Butt Connector w Adhesive Heat Shrink 16-14 AWG

Some of the crimps that look like these are heat shrink as well. They cost a little more.
I have often joined multiple wires on one side or both of a crimp and if careful it is OK, just like every other crimp.
Nicking the wire is bad, heat shrink is good
Also I like to run one PAIR of wires to each load and then connect them to the switch or buss individually. Then it you have a problem it is isolated to just the one device.
It also makes it easier to troubleshoot if there is a problem.
The cost is a little more wire and a lot more reliable.

[gordon2]

The issue of crimp vs. solder is another topic that has been debated since the invention of both.

IMHO, crimping is a perfectly acceptable method and very reliable IF DONE RIGHT. The problem is very few people know how to select the right connectors, how to properly crimp them and have the proper quality tool to do it. Most people use a multi-tool instead of a dedicated crimper. There is more to the science then it first appears. A proper crimped connection has mechanical strength whereas a soldered one does not except for the minimal amount provided by the solder itself. Try pulling apart wires that are connected with a proper butt connector, vs. just a soldered connection, and you will see what I mean. Its also a fact that the heavier the wire gauge, the less likely you will have success with solder. For heavier gauge, gas-tight crimped connections are what you want. (BTW, I have generally been one of the amateur crimpers also but I have been pretty lucky over the years).

I'll leave it up to others to do the research on how to properly crimp and decide for yourself what is best.

[redbarron55]

Aircraft butt splices (very expensive) have tow crimps, one for the wire and a second to locate the insulation.
Special calibrated crimpers do both at once.
By the way if you are buying crimpers get Thomas and Betts (T& or equivalent.
Note that these crimp along the wire and not across it which tends to cut the strands.
Back in the 70's the T&B aviation qualified splices cost about $0.50 each. I don't know how much now.

[Mike_L]

Electrical current is the flow of electrons through a conductor such as a wire. Most of the electron flow occurs through the surface of the conductor as opposed to its core. That is why a hollow pipe is a better conductor than a solid conductor of the same mass and composition. When wires are joined the objective is to fuse them together into one continuous conductor. This will minimize resistance and maximize current flow. Mechanical unions hold the two or more wires together. Current flow will be between the surfaces that come into contact with each other. Solder, when properly applied, contacts the entire surfaces of all the wire and effectively forms a complete union or fusing, of all the surfaces. This minimizes resistance and maximizes current flow. Mechanical unions rely on the friction produced by the device used to keep the wires in contact. Solder embeds the wires in a solid matrix. It is the rigidity of this solid matrix that binds the wires together. Mechanical unions may be subject to moisture infiltration which may result in corrosion as the wire oxidizes. These metallic oxides have a higher resistance than the original metal from which they form and impede current flow to the point where continuity may lost. When solder fuses to the wire moisture infiltration is prevented as there is no space for moisture infiltration. Mechanical unions offer speed and convenience of use at the expense of function, durability and cost. Solder is a little more difficult to use (properly) but is much more effective, durable and more economical to use. That's why most permanent electrical connections on a computer use solder. I have used solder not only for electrical unions on trailers but also in marine applications for over 40 years. I have never had one fail. In my experience, the wire will fail before the soldered union when the solder is used properly.