bool sequenceActivate = false
float sequenceDelay = 5;
float sequenceTimer = 0;

//check power over here - if it goes off, sequenceActivate = true
if(sequenceActivate){
    sequenceTimer += deltaTime;
    if(sequenceTimer >= sequenceDelay){
    switch (sequenceIndex) {
    case 1:
        //check if power is still off
        //if so, {
            sequenceTimer = 0;  //reset the timer
            sequenceDelay = 1;  //set the next delay to 1 second
            sequenceIndex++;
            }
    break;

    case 2:
        //turn on inverter via switch
        sequenceTimer = 0;  //reset the timer
        sequenceDelay = 2;  //set the next delay to 2 seconds etc
    break;

    case 3:
    break;

    case 4:
    break;

    case 5:
    break;

    case 6:
    break;

    etc etc
    }
}