There are many types of electrical cables out there with different types of insulation that allow it to be exposed to certain environmental conditions. Don’t forget, these cables also need to withstand certain voltage, amperage and temperature requirements depending on the application as well.
As for direct burial cables that have 2 AWG wires in them; a Tray Cable is the most universal type of electrical cable used in the industry. It’s basic, it’s round and it can be placed in conduit or buried directly in the ground if you so choose. The best part about it is the pricing. Copper weight cannot be changed no matter what happens, so if you’re looking for three 2 AWG wires in a jacket that can be protected from underground use then the insulation and the jacket will be the only differences in your search.
If you need a single conductor 2 AWG wire without an additional jacket you can use USE-2 solar panel wire. Don’t assume that it can only be used for solar panels because a 2 AWG copper cable is a 2 AWG copper cable. You’re looking for enough protection to use it underground and the insulation on a USE-2 cable has exactly that.
Some cables that get confused about direct burial are SOOW and Type W. SOOW is oil and water resistant and approved to be used outdoors but not in conduit or underground. Type W is an SOOW cable on steroids as it’s bumped up to 2000 volts from 600 with an additional rubber EPDM jacket for added protection. However, it still cannot be used in conduit or underground. The added protection is meant for industrial use on industrial job sites where machines will be running over the cable day to day.
So if you’re looking for a direct burial single wire you should use USE-2 and if you’re looking for a cable with multiple 2 AWG wires in it then you should use Tray Cable. Talk to your supplier about your application to make sure you’re buying the correct electrical cable. There is also different flexibility options you might want to consider for a slightly higher price.
You might be able to slightly downgrade the cable to save money and spend a less amount on conduit if your object is to save money. There are many scenarios that can be worked out so make sure you at least have the discussion with a professional before diving into an underground cable.