Tennessee Code Title 39. Criminal Offenses § 39-11-616

(1) The device is not designed to cause or known to create a substantial risk of causing death or serious bodily harm;

(2) The use of the particular device to protect the property from entry or trespass is reasonable under the circumstances as the person believes them to be; and

(3) The device is one customarily used for such a purpose, or reasonable care is taken to make known to probable intruders the fact that it is used.