You can detect electric fields when underwater, including bioelectric fields that surround all living things. This allows you to locate living creatures, electric transmission or communication lines, and anything powered by electricity. You can determine details of an object's electric nature (alive or artificial, high powered, rough voltage and frequency) but not other details (such as color, texture, shape). You can detect unpowered inanimate objects within about one body length of yourself, because they alter your own body's bioelectric field.
To detect a living creature or a "typical" electric powered object, make a sense roll. Apply modifiers for size and range, but not speed. Anything drawing exceptionally large amounts of electric current may have a larger effective size modifier for detection than its actual size modifier. A successful roll indicates the object's size, location, speed, and direction of movement. Once you have detected something, you can target it with an attack. The modifiers for your sense roll also apply to your attack roll, but will never give a bonus to hit.