hello,new to this site, i just bought a mep-oo2a with 26 hours on it,cleaned fuel system , changed oil, put new batterys on it it started right up works with no problems ,i want hook this up as a backup for my house, i know l-1 and l-3 are for 240 single phase ,can anyone tell me which post is the ground , i think it is l-o ,but want to make sure dont want to burn anything up,thank you