Knowledge (Demolitions)

Set an Explosive Device (DC of Device)
Setting an explosive device that has a set timer is done using this skill. Once the skill check is rolled, the device is considered active, and begins counting down unless a detonator is also installed. For every 5 that this check is exceeded by, the damage becomes more reliable. Treat all 1's rolled on the damage dice as 2's if the check is exceeded by 5 or less, all 2's as 3's if the check is exceeded by 10 or less, all 1's as 3's and all 2's as 4's and all 3's as 4's if the check is exceeded by 15 or less, and all damage done is maximum if exceeded by 25 or more. However, failing by 5 or less results in a dud, failing by 10 or less results in activating the 30 second count-down and increases the DC to disarm by 5, and failing by 15 or less results in activating the count-down, but not knowing about it. Failure by 20 or more results in an automatic detonation.

Identify Explosive Device (5+DC of Device)
This check allows you to identify an explosive device by sight alone. All penalties for distance are taken into account (see Perception), but success gives the knowledge of its name, blast radius, raw damage dice, and save DC.

Disarm Explosive (10+DC of Device)
This is the opposite of setting an explosive device. Succeeding on this check deactivates the explosive and prevents remote triggers from working (unless a secondary detonation device is in the explosive). Failing by 10 or less means the detonation timer is triggered. If there is no detonation timer, then the 30 second fail-safe is triggered instead. Failing by 15 or less means that the bomb is not deactivated, but the roller thinks it is. Failing by 20 or more results in an automatic detonation.

Action
Identifying an explosive is a swift action, but setting one usually takes one minute. Deactivating a bomb usually takes one minute as well. One can accelerate this to taking one full-round action by suffering a penalty (-5 to set, -10 to disarm).