A security system's power supply must be sized with headroom to accommodate additional devices, future expansion, and potential peak loads. ASIS PSP guidance recommends that the system load should not exceed
60% of the total power capacity.
* Loading above this threshold can reduce system reliability, limit the ability to add new devices, and stress power components, potentially shortening equipment lifespan.
* Maintaining a margin ensures that batteries and power supplies can support the system under normal and emergency conditions, including temporary peak loads.
* This practice aligns with standard design principles for redundancy, scalability, and safe operation of integrated security systems.

Comprehensive Detailed Explanation:
The three primary and sequential functions of a Physical Protection System (PPS) are:
Detection - identifying unauthorized activity.
Delay - slowing intruder progress.
Response - intervening before asset compromise.
This layered approach ensures an opportunity to detect and intercept threats before they succeed.
A and D include " deterrence " or " prevention, " which are security goals but not primary PPS functions.
C lists valid concepts but omits the critical detection phase.
References:
PSP Study Guide - Physical Protection Systems
POA Manual - Layers of Physical Security

Threats in security risk assessments are typically classified as either man-made (e.g., vandalism, terrorism) or natural (e.g., earthquakes, floods). This distinction helps define appropriate mitigation strategies.
A, B, and C describe other possible classifications but are not the foundational categories.
References:
PSP Study Guide - Threat Classification in Risk Assessment
POA Manual - Risk Types and Threat Sources