For construction information you will need to start a new thread asking for help building. Usually if you have tripped the breaker, you just need to rearrange the wires. THere are often a few builders lurking who can help with construction.
What was your temp everyday of the incubation? ANy spikes or drops?
Did you OPEN the vents during the last days of the incubation period? by day 18 . . . THe increase in air flow is very important as developing chicks each need more oxygen and air exchange as they reach hatching day; and need the most air when they hatch.
Other issues could be at play, but I would look at incubating conditions first.