Safety, Energy Production & Energy Consumption at Home

Short Circuits Accidental low resistance connection between two points in a circuit, causing excess current flow. Electrical devices will not work and will be dangerous – heat or fire.

Electrical Safety Handle electronics carefully Some electronics retain charge even after they are unplugged

Fuses and Circuit Breakers First of line of defense if something goes wrong. Fuse = safety device in an electrical circuit that has a low melting point, compared to wires. Circuit breaker = does the same thing but instead of melting, the wire heats up and bends which triggers a spring mechanism to turn off the electricity

Outlets Three prong plug – the third prong connects the device to the ground in the building. Extra or misdirected current goes to the ground instead of to the person.

Outlets Ground Fault Circuit Interrupter (GFCI) Any change in the current flow opens the circuit, stopping the current flow. i.e. if an appliance gets wet

Electricity Usage Cost –Every time you plug in an appliance or turn on a switch, electricity is being used. –Smart meters send usage of electricity on a house by house basis to the electric company so that the house gets charged the right amount

Electrical Energy Consumption Amount of energy used is calculated in kilowatt- hour (kW●h) If a microwave is 0.8 kW and the oven is turned on for half an hour E = 0.8 kW x 0.5h = 0.4 kW●h To calculate cost you multiply the energy consumed (kW●h) at the cost per hour (which can vary depending on time of day). –There are additional charges as well like delivery costs and taxes,

Efficiency Light bulbs get hot…there is an inefficiency due to the fact that not all the energy is being converted to light, some of the electrical energy is being converted to heat. Efficiency = ratio of useful energy that comes out of the device in relation to energy that went % efficiency = E out X 100% E in

Comparing Efficiency Some appliances are better at using electrical energy than others Energuide – average energy use in a month or year Energy Star – means the appliance is one of the most efficient appliances in its class.

Is it Off? Numbers relate to if the device was in standby all day long, every day for a year. Black = energy used Red = energy cost if $0.14 per hour