I currently have a 50' length of 14/2 UF-B. I only need to dig a 40' trench, but I know it should be buried 24" deep. That seems like it will be a lot of work to bury it that deep. It seems like it would be a good idea to run it through some form of conduit so that I don't have to dig so deep. There's also the added benefit of being able to run a different size cable in the future. I'm not sure if there are different requirements with running UF-B through conduit, so I'd like some advice on which conduit I should use, or how I should dig this trench more easily.
I assume that the 14/2 UF-B is still the cheapest cable option. I looked into renting a trencher, but the cheapest I could find was $150 for 4 hours. since it's a 40' trench, it didn't seem worth the price if I could just use a shovel. PVC conduit is pretty cheap, but as far as I can tell, it still needs to be buried to a depth of 18". As far as I know, the only other option is IMC, which only requires a depth of 6". Looks like I can buy 10' lengths of IMC for $16 (so $64 for 40'). I don't know if there are any other options. I found 50' length of flexible PVC conduit for $35, which is cheaper, but I'm not sure how deep it needs to be buried.