1) What area are you most nervous about for the midterm? A.Residential electrical systems B.Commercial electrical systems C.Panel and branch circuit sizing D.Lamp technology and light level requirements E.CU calculations and fixture calculations

Objectives Review material for midterm Electrical systems Lighting systems Review session ECJ (this room) on Monday 10/4 at 5pm

Electrical Systems What is NEC? What does it tell you? What is single phase power? What is three phase power? How do you calculate power usage? How do you size conductors? What is conduit and how do you size it? How do you calculate electrical bills for a commercial building? For a residential building?

Residential Electrical (1Ø) How many phases are there? How many voltage levels? What voltages are typical? How does air conditioning influence the required electrical load? How is central heating accounted for differently from non- central heating? How do you size the panel

Commercial Electrical (3Ø) What is a branch circuit? What is the difference between MLO and MCB? What is the difference between single pole and multiple pole loads? What is the difference between 2 and 3 pole loads? How do divide the wattage among legs for multi-pole loads?

Commercial Panels How do you find the total load on each neutral leg? On each hot leg? How should you size the hot feeders? How should you size the neutral feeder? How should you size the panel? How should you size the conductors coming into the panel? Do you need to size conduit for the panel feeders?

Branch Circuits What is a branch circuit? What is an example of a branch circuit rule? How do you size the circuit breaker for a branch circuit? Is the procedure different for a multi-pole breaker? How do you size the conductor for a branch circuit? When do you use the 1.25 safety factor? When do you use √3?

Commercial Electrical When do you need a transformer? How do you size it? How do calculate the current coming into a transformer? Why do we segregate loads on panels? When do you need to size a switch? How do you size it? How do you size a wireway? What do you do if no conductor is big enough?

Electrical Systems What is the most confusing thing about electrical systems? What is the least confusing thing about electrical systems?

Lighting Design What is the difference between illuminance and luminance? What is a lumen? Does it relate to illuminance or luminance? In addition to quantity of light what are five other variables which influence lighting design?

Lighting Quantities and Quality What is CRI? What is lamp lifetime? What is efficacy? How does it differ from efficiency?

Lamp Technologies What are three different kinds of lamps? How do halogen lamps differ from incandescent lamps? How do fluorescent laps work? How do HID lamps work? What is a ballast? When do you need a ballast? What lamp has the highest/longest CRI/lifetime/efficiency?

Determining Required Lighting Levels Where do you start? What other pieces of information do you need to know? What is a weighting factor? How many parameters contribute to the weighting factor? What is the difference between a lux and a footcandle?

CU calculations What is CU and what does it mean? Where do you start when calculating CU? How does room geometry influence the CU? What is PAR? What is a CR? What is the difference between a base reflectance and a cavity (or effective) reflectance? What symbols do you use for each? How do you calculate effective reflectances?

CU Calculations Once you have the CR and effective reflectances how do you find the CU? When do you have to calculate the floor cavity reflectance? What do you do if it is not 0.20? Once you have the CU, how do you calculate the number of fixtures? What is S/MH and how does in influence the fixture calculation?

Your Turn - Questions?