Devices (TV, Refrigerator, etc) are rated for maximum power/voltage/etc. (They stop working if exceeded) Devices can be overpowered by accident by  overloading outlets – draws too much current  Example: plugging too many things into the same outlet  Ground Fault (short circuit) – contact is made between live and ground conductors  Example: Working hair dryer in water – plumbing is connected to ground

Preventing Accidental Overload  Fuses  small filaments (like light bulbs)  Burn out when too much current is drawn  Circuit breakers  bimetallic strip heats up when too much current is drawn  bends when heated which opens switch to prevent current flow   GFCI outlets and breakers  Complex circuitry that senses too much current almost instantly  Opens circuit at outlet or breaker 

0.00l A and higher – feel shock 0.01A and higher – unable to release 0.02 A and higher – paralyzes respiratory muscles (you can’t breath) 0.1 A and higher – ventricular fibrillation (erratic heartbeat) 1.0 A and higher – “cooked”

Skin has very high resistance – approximately 100,000 Ω So, V = IR 10 V = I (100,000 Ω ) I = A Remember! You can’t have a current without a voltage