# Electrical Flashcards Preview

## Building Science > Electrical > Flashcards

Flashcards in Electrical Deck (23)
1
Q

What are the two types of electric circuits in a home?

A
```Power circuits (house voltage) - heat, light, motion
Control circuits (low voltage) - regulate furnaces, water heaters, and appliances```
2
Q

A circuit is composed of three parts:

A

Source (power plant), path (wires), load (device)

3
Q

Switches are used to:

A

open and close a circuit

4
Q

Series circuits

A

Have only on continuous path
Not used to connect multiple loads

5
Q

Parallel circuits

A

Have multiple paths, each containing a load

Most home circuits are wired in parallel to ensure consistent voltage to all loads

6
Q

Control circuits provide precise control of energy systems. What are their components?

A

Transformer - reduces voltage down to 24V
Controller - sense environmental conditions or user input
Control element - pump, gas valve, burner, fan, etc

7
Q

What is Ohm’s Law?

A
```E = I x R
Voltage = Current x Resistance```
8
Q

What is voltage?

A

Electrical pressure or force measured in volts

9
Q

What is current?

A

Flow of electrons measured in amps

10
Q

What is resistance?

A

Opposition to current flow measured in Ohms. Produces work

11
Q

What’s the Power Law?

A

Current x Voltage = Power in Watts

12
Q

Describe how electricity gets from power lines to a house.

A

Service drop extends from the utility pole to the electrical meter of the house (2 120 V hot wires, one neutral structural wire).
Feeder wires connect the meter to the panel box.
A grounding wire connected to the panel metal is connected to the neutral feeder and attached to a copper grounding rod driven into the ground.

13
Q

What are the two types of circuits in a house?

A

Branch circuits - serve multiple loads such as lights, fans, outlets, etc.
Appliance circuits - serve a single appliance each like refrigerator, water heater, heating system, etc.

14
Q

What’s a short circuit?

A

The flow of electricity through a circuit that does not contain a load or contains a very low resistance load. When resistance drops near zero, max current is produced.

15
Q

Short circuits occur because of:

A

Sticking something in an outlet, disconnected wiring, worn insulation, damaged cords, etc

16
Q

A branch circuit wired with 12-2 wire should have a max ___ amp breaker that protects the wire from overheating if too much current flows.

A

20

17
Q

Circuits wired with 14-2, or older house branch circuits, should have a max ___ amp breakers.

A

15

18
Q

What’s a fault circuit?

A

The accidental flow of electricity through a stray circuit that is not part of the electrical system of the house. Common in presence of water.

19
Q

What’s a GFCI?

A

A Ground Fault Circuit Interrupter protects outlets in wet locations. It trips instantly if it detects any mismatch in current between the hot wire and the neutral wire, indicating a fault.

20
Q

What’s the top left hole in an outlet?

A

Neutral

21
Q

What’s the top right hole in an outlet?

A

Hot

22
Q

What’s the lower center hole in an outlet?

A

Ground

23
Q

What are some common electrical problems?

A

Unlabeled panel, overloaded receptacles, oversized fuses/breakers, reversal of hot/neutral, missing GFCIs, sharp screws in panel cover, ungrounded outlets and metal, pipes not grounded, etc.