The reason why ground straps are uninsulated is because ground straps don't have any actual voltage that can create a shock like a normal electrical wire would.
Using insulation on the ground strap would make it less flexible and cost more to produce and because the ground wire or ground strap is connected to the vehicles chassis which is metal it does not need insulation to prevent it from shorting out.
The positive wire needs insulation to prevent it from coming into contact with the ground and shorting the battery and vehicles electrical system out.
The insulation on a grounding strap can also hinder the direct, low resistance path to the ground for the current to flow in the event of a fault or surge.
Ground straps without insulation conduct the current better and are more flexible.
The reason why grounding straps are flat is because the flat grounding straps have more and better conductivity of the electricity and are more flexible which makes them easy to install and prevents them from breaking as easy.
Flat ground straps also perform better at higher frequencies than regular ground wires.
A braided ground strap also has more strands of wire than even a regular 4 gauge battery cable and the strands are smaller in diameter.
Simply increasing the diameter of round conductor ground wire doesn't reduce the inductance significantly and ground wire is good for power frequency applications.
Although the flat ground straps are better at higher frequencies.
A green ground strap is bad as it's a sign of corrosion and deterioration and can cause a bad ground connection and cause electrical problems in the vehicle.
If the green corrosion is not all that bad the ground strap and connections can sometimes be cleaned using some baking soda and water and a brush.
However if the ground strap is really corroded and is coming apart then it's best to replace the ground strap with a new one and clean up the connections.
The ground strap turns green as the copper wire ages and is exposed to air and forms the green color from oxidation and will also often have signs of corrosion that affect it.
Your ground cable may still look okay but still have excessive electrical resistance deep within the wire somewhere.
The benefits of a ground strap is that they allow for and improve the grounding path for the circuit to complete in a DC system such as a vehicle.
Adding ground straps to a vehicle helps improve the conduction of the vehicles electrical flow and protects people and equipment in your vehicle from damage and electrical shock.
The ground strap provides a safe path for excess electrical current to flow through and provides a low resistant path for the electrical current to flow through to the ground.
If you have too much electricity that is traveling to or from an electrical component then the ground strap will be able to disperse that excess electricity.
The electrical components are often connected to the engine and are then connected to either the chassis of the vehicle or a negative battery terminal.
Ground straps on vehicles are essential in protecting your vehicles electronics including the ignition modules, coils and other important electronics in the vehicle.
The symptoms of a bad ground strap are flickering lights, low voltage readings, battery warning light coming on, electrical malfunctions that can be intermittent across the vehicle and even sometimes difficulty in starting the car or a dead battery.
The symptoms of a bad ground strap on a vehicle can vary and may not always show all these symptoms and may only cause some of these symptoms or only one or a few.
If you have a good ground wire otherwise you may still have a proper charging battery from the alternator and may still be able to start your vehicle with no issue.
A bad ground strap could cause you to fry ignition control modules, lead to voltage fluctuations, may cause static in the radio and could cause interference with other electronics in the vehicle.
Headlights or other lights on or in the vehicle may flicker with a bad ground strap as a result of inconsistent power supply that is caused by a poor ground connection.
In some cases the bad ground strap may prevent the alternator from properly charging the battery.
A bad ground strap may also cause low voltage readings and sometimes the other electrical components of the vehicle such as the AC compressor clutch may not work properly or the windshield wiper motor or window motors etc may not work properly or intermittently as a result of a poor ground connection from the ground strap.
The dashboard battery warning light may also illuminate due to issues with the charging system due to a bad ground strap as well.
It's always better to have more ground straps than too little or no ground straps at all.
There should always be a ground strap from the engine to the firewall and even from the engine to the frame if you vehicle has a frame.