Question: Im making a growroom outdoors about 250ft away from nearest powersource. What's the easiest and cheapest way to acquire that power? Buying 10/3 gauge wire is expensive. Dollar fifty a foot. So any and all help would be greatly appreciated. Thanks.
if using romex,you need 10/2 (it has 2 wires plus a ground wire) if you use extension cord wire ,you need 10/3. standard 10/2 romex will cost about $100 for a 250 roll. romex rated for direct burial will be almost double. that being said,standard romex will last for several years if buried- I buried a 12 foot piece to my gazebo about 8 yrs ago w/out problems...YET!
another option is to buy PVC pipe (under $2 for a 10 foot stick) & run the wire in that.last time I bought 10 gauge Thhn wire, a 500 foot roll was about $75.-Thhn is a single conductor that needs to be run in pipe so you would need 750 feet. $80 should cover the cost for 1/2 pvc pipe,clamps &boxes needed.romex or extension cord wire should not be run in pipe.
cheapest option would be to buy a 250 roll of 12/2 romex & use the extension cord you already have & double them up- tie both blacks together,both whites,& both grounds.this is not to code for many reasons but would be reasonable safe for several yrs & give you the power you need.I'm guessing if found, electric code violations are the least of your problems.
to review
best & to code would be PVC and Thhn wire-this would be to code & allow another circuit to be added later- a little over $200
next would be direct burial 10/2 Romex- also to code & under $200.
breaking code but safe for short term(4-5 yrs) would be 10/2 romex not rated for burial.-about $100
cheapest/dirtiest but safe for short term,12/2 romex buried w/ the 12/3 cord you already have & joined at both ends