Smartplug Connection Quality

[pittjw]

Installed both ends of a Smartplug BA50ASSY on my 50 amp Airstream. Im not 100% pleased with the quality of the connection. On the trailer end, there is stranded 6 awg 3 conductor with an 8 awg stranded bare ground. Bending these in to the perfect configuration wasn't easy as they must insert together with wire this stiff. Thats not the issue. The mechanical connection inside of each lead "hole" is provided by a very nice socket head screw with a swivel washer at the end of the screw. In my opinion, this screw does not mechanically bind all of the conductors against the back of the hole. This was especially the case on the cord end where I installed the SmartPlug end on to the stock Airstream cord. Side note, the Airstream cord had half moon shape crimp connectors on each conductor to maximize surface area and screw "grip" (see photo). The Smartplug end is the same as the above description only this connection (again my experience/opinion) when tightened against the finer stranded 6 awg wire of the stock cord does not bind all of the strands. see photos... Would appreciate any experiences with 50 amp installs.

[uncle_bob]

Hi

There are multiple types of wire you *could* use for this. Solid wire is uncommon, but it certainly is out there. Coarse ( = large strands ) stranded wire is the norm. That's what most connectors are designed to use. If you go with very fine stranded wire then you need to add some sort of crimp on gizmos.

Bob

[goldenchase]

Originally Posted by pittjw

Installed both ends of a Smartplug BA50ASSY on my 50 amp Airstream. Im not 100% pleased with the quality of the connection. On the trailer end, there is stranded 6 awg 3 conductor with an 8 awg stranded bare ground.

I had the same reaction. During the electrical conversion of my GT I replaced all of the 6/4 cable I could get to with much higher quality cable from AMSolar. There is a short segment that goes under the floor from the left side of the trailer to CB panel I could not get to.

The AMSolar cable is very stout and fits nicely into the fittings on the plug with all cables 6 gauge. This is a 50 amp connection.

[Mx468]

Get something like this to crimp onto the end of the wires and then put into the smart plug and tighten.


https://www.amazon.com/Baomain-AWG-L...a-569041046809

[pittjw]

Thanks for the responses. I ordered crimp terminals and have been experimenting with crimp devices, most of my crimp methods (hydraulic with 6awg dies, standard hand crimper, advanced ratcheting crimper) end up creating a protrusion on each side (with the sleeves i had) and would not fit in the terminal hole. Once its forced in then tightened, likely cant remove (easily). I am going to try and create a die with a half round bottom like the factory cord had. hopefully the new sleeves above will work better as the crimped terminal must deform to the hole imo to guarantee a good connection at this current level.

[jeffmc306]

pittjw , in the past I’ve tinned wires with solder to bond them together and make one solid connection similar to the Airstream connector in your photo. Just a thought in case you’re not able to get a crimped connector to fit.

[goldenchase]

I don't think these Smartplug fittings were designed for anything other than bare #6 wire. I had a hard time getting a tightly twisted #6 wire down into the fitting for each wire. Very close tolerance.

[richard5933]

Originally Posted by jeffmc306

pittjw , in the past I’ve tinned wires with solder to bond them together and make one solid connection similar to the Airstream connector in your photo. Just a thought in case you’re not able to get a crimped connector to fit.

Tinned wire ends for screw-down terminals is not considered best practice. The solder will migrate over time and result in a loose connection.

Much better is to use a crimped ferrule on the stranded wire, something which is common practice in many parts of Europe to avoid the problems described in the initial post.

If you cannot get the crimped ferrule into the terminal due to the flared end on it you can also get ferrules without the flare. You can also get crimping tools which make square ends or hex ends, and I've found that the hex-shaped crimp is much easier to insert into smaller openings in terminals like this one.

I make it a part of the spring maintenance to re-torque the terminals on all my 120v power feed circuits, and over the years I've found that the connections made with ferrules require re-torque much less often than the ones made to the bare strands.

[uncle_bob]

Originally Posted by jeffmc306

pittjw , in the past I’ve tinned wires with solder to bond them together and make one solid connection similar to the Airstream connector in your photo. Just a thought in case you’re not able to get a crimped connector to fit.

Hi

There are a couple of issues with tinning stranded wire. The first is (as mentioned above) that solder is a bit soft. Put pressure on it and it will deform.

Next up is that you create a transition between "stiff" tinned wire and really flexible stranded wire. Stress is focused at this point and the tiny strands tend to break. As they break, stress goes up and more break.

This one is a bit insane. When you tin a wire, part of the copper is dissolved into the solder. That creates a "neck down" effect. It's pretty small, but for fine gauge wire it's significant. It creates a weak point right at the transition between "stiff" and "flexible". This is not what you want to have.

Necking down is also an issue with crimp connectors. It is one of the reason that each connector out there has some sort of die / tool combo you are supposed to use with it. Often that tool setup is quite hard to track down and crazy expensive when you do.

Bob

[jeffmc306]

richard5933 and Uncle Bob, thanks for educating me about why you shouldn’t be tinning copper wire. A crimped ferrule would be a better choice. Learn something new every day.

[waninae39]

best to use a crimped ferrule on the stranded wire
i do that on most connections

these are easy to find on amazon etc

[jeffmc306]

I was curious about ferrules and the crimp tool and came across this short YouTube video from EXPLORIST life - DIY Campers. Worth watching for anyone interested.

[richard5933]

That looks similar to what I use. They have both the square crimp that you show in the thumbnail and a hex crimp tool which is nice for terminals with narrower openings.