There is a standard mutual aid agreement developed by The Edison Electric Institute, but the whole concept is becoming outdated, in my opinion. Even with the agreement in place, the other company being requested to help out has a right to decline, and they get reimbursed for everything even if they do respond. For this reason, you'll find just as many contract crews helping out during a big storm as you will mutual aid crews. Some linemen don't even like mutual aid crews, since they'll do some "suff", we'll say. They are business competitors, after all. If a company does respond to a mutual aid request, the linemen are usually taken first on a voluntary basis and mandated next. There are always a certain amount of guys who'll suck up all the OT they an get.