For a 30AMP breaker I think you need 10 guage wire. I know you need 12 guage for a 20Amp breaker. Anyhow this should be printed on the wire. Anyhow make sure you match the right wire to the breaker if not you defeat the purpose of having the breaker the wire will burn up first before tripping the breaker and could cause a fire. However if you are not goting anything I doubt it is the wire fault unless you totally ran the wrong thing like zip cord or something then it is possible it is not carrying enought current to start the thing.