S95 Components and Power 3

Question 1

A Class B Initiating Device Circuit (IDC) differs from a Class A circuit primarily because:

Accepted Answer

A single open-circuit fault on a Class B circuit renders all devices beyond the break inoperable

Answer

Class B uses a single-path topology; one open fault breaks continuity and disables all devices beyond the break, unlike Class A's redundant looped return path.

Question 2

What is the primary purpose of an End-of-Line (EOL) resistor installed at the far end of a supervised circuit?

Accepted Answer

To allow the panel to continuously detect open or short faults by monitoring a baseline current

Answer

The EOL resistor establishes a known baseline current that the panel monitors; any deviation from this value indicates an open, short, or ground fault on the circuit.

Question 3

What causes a 'ground fault' trouble signal on a fire alarm Notification Appliance Circuit (NAC)?

Accepted Answer

An unintended electrical connection between a circuit conductor and the building's grounding system

Answer

A ground fault occurs when a NAC conductor makes unintended contact with a grounded object such as conduit or structural steel, creating an abnormal current path the panel detects.

Question 4

In a Class A Signaling Line Circuit (SLC) configuration, what occurs when a single open-circuit fault develops?

Accepted Answer

The circuit splits into two segments, both of which remain operational via the loop's return path

Answer

Class A SLC uses a looped return path, so an open fault divides the loop into two segments—each still connected to the panel from opposite directions—maintaining full device communication.

Question 5

Which cable type is required for fire alarm circuit wiring that must remain functional during a fire to support emergency operations?

Accepted Answer

Circuit Integrity (CI) rated cable or equivalent fire-resistive mechanical protection

Answer

Circuit Integrity (CI) rated cable maintains electrical continuity for a defined period when exposed to fire, ensuring critical circuits operate throughout the emergency.

(S95) Supervision of Fire Alarm System Practice Test

(S95) Supervision of Fire Alarm System Practice Test

S95 Components and Power 3