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How much wattage do you add per inch when connecting flex watt?
thanks,
-Blue

Can you clarify what you are asking? Is it the wattage rating of the cord per length of Flexwatt?

What Flexwatt? The 11-inch wide? The 3-inch wide?

11-inch is 20 watts per foot (there is also a 10 watt/ft 11-inch type, but most that is sold online is 20W/ft).

3-inch is 8 or 10 watts per foot, I forgot. Some suppliers sell the 6-watts-per-foot 3-inch stuff. Assume 10 watts per foot for calculations and you will be safe. Using the higher number guarantees safety if the actual wattage is lower.

4-inch is 8 or 10 watts per foot. Again, I forgot which was which. Use 10W/ft in calculations for safety.

18AWG cord is rated up to 10A max. 16AWG cord is rated at about 13 amps max. Consider 1000W max for 18AWG and you will be safe. Consider 1300W max for 16AWG and you will be safe.
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Mark

oops, you got my question for me Mark. I was looking to see how much wattage I should account for per piece of electrical wire when running flex watt in a series then plugging that series into a proportional thermostat. I am going to be using both 3" and 11", the 3" will be back heat run in strips of 4' in a series and the 11" will be made into 2' pad linked in a series... I think, unless told that this is a bad idea.... then I have to think of something else... or burn the house down...
Thanks,
-Blue

Ha ha.

No problem. I know you know this, but just to be thorough, your limiting factor is the wattage rating of your proportional thermostat. If that is, say 500W, then you cannot exceed that much in Flexwatt.

I would use 3" Flexwatt for belly heat, and 11-inch Flexwatt down the back of the rack. Better safety to have less surface area for belly heat, and much easier to attach a single (or two if your room is cold) piece(s) down the back instead of four.

Your idea of back heat AND belly heat is fine. When the room is warm, you may find you only need to use the back heat. When the room is cold, you may find you need both or else just the belly heat depending on the species (temperate or tropical) or mass of the snake (bigger snakes need heat over a wider area, etc).

If you go with the back AND belly approach, my advice to you is to use two controllers. Back heat is less dangerous, so you can get away with a less expensive controller. An ON/OFF thermostat will even work for back heat, though proportional gives you better control. Honestly, the $40 ON/OFF models are fine for this application. You can even put a dimmer in-line and just use the thermostat to trip at a high temp cutoff. In other words, the dimmer is used to fine-tune the heat, and the thermostat shuts it off in case temps get too high.

For belly heat, stick with the proportional controller for best results, but you could do the ON/OFF thing if you want.
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Mark

Gottcha, I think I am going to use the 3" for back heat as the rack will be inside. The 11" was going to be a heat pad application for my boas, but again I think I may shell out for some RHPs as I will only need about 10 (over the course of a year..). If I go with the cheap end Helix I can get 300 watts of safety. but I do have alot of dimmers laying around too... so many choices. so little money...