Electrical Circuits and Wiring Diagrams 080204bB

Question 1

What does the E represent in Ohms law and what are the different names for it?

Answer 1

Voltage, EMF, Pressure

Question 2

What does the I represent in Ohms law and what are the different names for it?

Answer 2

Amps, Flow, Current

Question 3

What does the R represent in Ohms law and what are the different names for it?

Answer 3

Ohms, Resistance

Question 4

What is Kirchhoffs law?

Answer 4

The sum of all voltages in a closed circuit is zero

Question 5

Extra low voltage circuites are restricted to what?

Answer 5

Maximum of 30V and a maximum power level of 1000 VA

Question 6

What 2 conditions must a class 2 circuit meet?

Answer 6

The voltage of the circuit must be 150V or less

The maximum power output of the circuit supply must be restricted to 100 VA

Question 7

The benefits of limiting a circuit to Class 2 are what?

Answer 7

You are permitted to use conductors smaller than #14 AWG

The circuits often require a lower level of mechanical protection

Question 8

How far away from a gas meter or relief decice must a switch or other electrical device be?

Answer 8

3’ (900mm)

Question 9

When must a class 1 or class 2 circuit be grounded?

Answer 9

When supplied from a transformer with a secondary voltage ranging from 50V to 150V

Question 10

When does a class 1 or 2 circuit not need to be grounded?

Answer 10

If the transformer has a secondary voltage of less than 50V and the primary voltage is 150 volts-to-ground or less

Question 11

Where distance must a disconnect be installed in relation to a rooftop mechanical unit?

Answer 11

10’ (3m) and within sight

Question 12

What are the 2 types of conductors that are approved by the CEC for Class 2 conditions of use?

Answer 12

LVT (extra-low-voltage control cable)

ELC (extra-low-voltage cable)

Question 13

What kind of cable would you use to wire a 24V thermostat (heating control)?

Answer 13

LVT (extra-low-voltage control cable)

Question 14

Whats another name for a load device on a circuit?

Answer 14

Actuator

Question 15

What types of load devices are composed of a coil (the load device) and contacts (the controlling device)

Answer 15

Relays and magnetic contactors

Question 16

What is one of the easiest ways to determine the way a piece of equipment works?

Answer 16

Study the schematic

Question 17

What 3 components does an electrical circuit need in order to work?

Answer 17

Power source

Load

Conductors (joins the 2)

Question 18

What type of diagram shows an eletrical circuit without regard to the physical location or actual appearance of the components?

Answer 18

Ladder diagram

Question 19

What type of wiring diagram shows where the wires go, the route they take and the connection terminals?

Answer 19

Connection diagram (line diagram)

Question 20

What are the function of the R and W on a thermostat?

Answer 20

R = power to stat

W = power from stat

Question 21

What shows the maps or graphical representations of a process?

Answer 21

Flow charts (found in operating manual)

Question 22

Control decices on a ladder diagram are shown in what state?

Answer 22

Normal positions with the load devices de-energized