Reptile & Amphibian Forums

I am building a rack system using dimmers instead of thermostats( using a heat gun to set temps.).The racks are housed in my basement(which maintains a constant 68 deg.) so heat fluctuating is'nt a problem.My question is has anyone used dimmers without thermostats with no problems(i.e. dimmer failure, heat fluctuations, ect.).I have seen companies use dimmer faliure as as what I see a selling point for their thermostats, but if a dimmer is hooked up properly I don't see any problems having to use a thermostat.Am I wrong??? Thanks in advance for any feedback.

I've been wondering the same thing. My basement also stays pretty consistent year round and I have been using an in-line dimmer and set it with a thermometer and taped it off so physicaly it wont go up or down and then I hooked it up to a timer that is set to go off at night. So far no problems but I have read the same horror stories that they can get locked in the "open" position cooking the prize animals.I'm not at all knowledgable about electrical stuff and don't understand how that could happen so I hope we hear from someone who really knows what their talking about. Good luck.

PS. I'm in my 40's and have never heard of any freinds or family members whos home thermostats have failed. Maybe I've just been lucky.

I dont use dimmers on cages...but I have had one light dimmer (for the lights in my home) get stuck "on", it actually started a small fire in the dimmer switch itself. Didn't seem to do anything with the lights....but the dimmer was toast. I dont know how it would have effected heat tape or any other heating device.

Worst case you can allways route a cable like this.

Wall outlet, dimmer, thermostat set 5 degrees higher then you want, heat tape. Think of the thermostat as a failsafe. That way you can allways turn the dimmer down a little bit....but if the dimmer sticks on, and the heat tape keeps getting hotter and hotter the thermostat will cut the power.
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Tegan

Since dimmers are solid-state devices, there is a possibility that a power surge can fail the device, but most failed dimmers are the direct result of the end user shorting the wires together on the load, or a flawed heating element that does just that. A failed dimmer will usually fail "ON". You can minimize failure of any device by using a good surge protector and plug the dimmer into that. Also, don't use poor wiring methods and make your connections secure.

I've been using dimmers for many years and fortunately haven't had an issue. The two people I know that had failed dimmers had this scenario: one guy was using a 10-year-old dimmer (please, they aren't that expensive to replace every 5 years) and no surge protection; the other guy wired his wrong.
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Mark

I'm not an electrical engineer, but...
if you are running more than the rated wattage for a dimmer, wont that cook it? Also, there are some issues with impedance due to overloaded connections...ie...surge protector, dimmer, thermostat. Each one of these pathways along the way impedes the flow of electricity. This in turn will over heat the device, or devices. Creating a fire hazard within the unit itself.
The main thing is, check the dimmer for the recommended max wattage, and adhere to that, and dont go hooking up 5 or six different devices into one circuit, as each device wired in series only adds to the overheating problem, cooking the dimmer as well.
To do otherwise, is inviting trouble.
Also, on the subject of power surges. Would'nt the opening of the thermostat,turning on the electical flow to the heat tape be a power surge?
Not much of one. Probably less than turning on a 100 watt light bulb with a dimmer.
When using electrical devices, one cannot be too careful.
Did any of this make sense?...lol
Sorry, we're tired tonight.

Adding more devices i.e. surge protectors, thermostats, etc at worst REDUCES the power ever so slightly to the load. This doesn't cook anything. I have been doing this for years.. surge device to thermostat to dimmer. Your first statement though is correct - going over the wattage rating can be disasterous.

As for the power surge: when you apply power to a light bulb, the initial resistance of the cold filament is very low, causing the device to draw alot more current (like 2x up to 5x) for an instant than the light draws when it is on steadily. The triac in the dimmer is made to withstand a high current load as long as it is not longer than a few milliseconds, which is the case normally. So, this kind of power surge is normal. It is a current surge, not a high voltage surge. Surge protectors protect against high-voltage spikes on the AC line. Although most triacs are darn tough and can even withstand a fair amount of voltage spiking, using a surge protector only makes things a bit less severe for any device.
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Mark

I have been using dimmers from walmart know for 4 years and have never had a problem...I would consult an electricain to be sure as my brother in-law is an electrician.

Paul