Quote Originally Posted by suzuki4life View Post
So by placing the probe directly on the heat tape, how often does your thermostat turn on and off? Depending on ambient temp of the room, the thermostat could be flickering on and off at a high rate. Flickering on and off of thermostats can cause failure by over working them. i've seen many cheaper thermostats that fail in the "on" position. When this happens, your heat tape runs at full voltage, it is now unregulated and uncontrolled. I have a friend who had exactly this happen to the point he fried the snake. Yes it died.

Dimmer switches can fail. If they fail, the circuit is interrupted and power is then lost. No shorts to worry about. So worst scenario, the snake falls to room temperature if setup my way. Do it the other way, thermostat fails in "on" position, flexwatt overheats,and fire occurs. Not worth the risk over lacking the use of a dimmer switch.
I get what you are saying but dimmers in the set up do not allow the t-stat to do its job. If the room temp drop the dimmer will not allow the heater to get to a temp warm enough to provide adequate heat. I agree a fail safe is not an optional tool. Especially in racks too many moving bits around the probe. But I disagree that a dimmer is the way to do so. I would use a second t-stat the chances of both failing and both failing open are so long to be not worth discussing.

If that is added to the modern T-stats that have over and under and secondary error finding circuits those odds are even farther away. Rheostats also do not kill the power they just restrict it. Your first comment they will not prevent a fire as power is still running a failsafe t-stat stops the power in the event of over load.

My safety systems are simple GFCI outlets in the snake room, Smoke alarm, Tstat's backed by failsafe t stats, monthly inspections of all connections and flexwatt panels. Oh there is also a fire extinguisher in the room too.