And you wonder why your UTH burned out.
Any heat source MUST be regulated, a thermostat is not a useless gadget it is the single most important piece of equipment when it comes to husbandry.
Snake will burrow so even if you think that your substrate in someway protects your snake, think again.
Additionally any heat source can and will over heat which means not only it could result in severe burns, death but a fire and loosing your house is also a possibility.
Do yourself a favor buy a RELIABLE UTH and a RELIABLE thermostat the best place to do so is here. http://www.reptilebasics.com/