CCTV & Security

Standalone vs networked access control; 125 kHz proximity (easily cloned) vs 13.56 MHz DESFire EV3 (AES-128); OSDP v2 vs Wiegand; fail-safe locking on fire exits mandatory; biometric = Special Category GDPR data (explicit consent required)

ARC must be BS EN 50518/NSI listed for police URN; PSTN being withdrawn — use IP+4G dual-path; ATS categories 0–6 by grade; Grade 3 requires ATS4 minimum; URN applied by ARC not installer

BS 8418:2015 registered CCTV: image quality (pixels/metre), video analytics for false-alarm filtering, ARC requirements, commissioning certificate content

50 mm segregation from mains (100 mm at crossings); screened cable for PIR, RS-485, runs >50 m; earth screen at one end only (controller end); voltage drop formula for DC runs; cable schedule mandatory for NSI/SSAIB compliance

CCTV camera selection: fixed vs PTZ vs fisheye, IP67/IK08 ratings, IR and white-light illumination, WDR, pixels/metre for identification, lens focal length

Communal areas permissible (legitimate interests basis); inside private dwelling requires explicit tenant consent; household exemption does not apply to landlords; 30-day retention recommended; SAR must be answered within 1 month

Audio vs video vs IP intercom; fail-safe vs fail-secure locking; maglocks fail-safe (open on power loss); electric bolts fail-secure (never on fire exits); fire release via panel dry contact mandatory; break glass unit on fire exit secure side

GDPR for CCTV: ICO registration tiers, signage requirements, retention periods (7–31 days), Subject Access Request procedure, domestic exemption limits

BS EN 50131 Grades 1–4: Grade 1 opportunist/low-risk; Grade 2 standard domestic/commercial; Grade 3 medium-high risk with ARC dual-path (30 hr standby); Grade 4 high-risk dual-path mandatory (60 hr standby); PD 6662:2017 risk assessment mandatory

NSI and SSAIB approval: Gold vs Silver grades, police URN eligibility, annual audit process, why insurers require approved installers

NVR vs DVR and storage sizing: HDD capacity formula (Mbps × 0.45 × hours × cameras × days), surveillance HDD selection, RAID, H.265 vs H.264, retention period configuration

Mount at 2.0–2.4 m; cross-axis detection superior to end-on; pet-immune masks below 50–60 cm (climbing defeats it); anti-masking mandatory Grade 2+ (BS EN 50131-2-2); dual-tech for high false-alarm environments

Walk test every detector individually; test all tamper circuits; ARC commissioning signal test; exit/entry timing verification; end-user training mandatory; commissioning certificate signed by engineer and customer; factory default codes always changed

Grade 1–2: 1 inspection/year; Grade 3–4: 2 inspections/year; every detector tested at each visit; ARC notified before testing; battery replaced on visit if low; service report signed engineer + customer; lapsed contract risks URN withdrawal and insurance void

868 MHz FHSS; Grade 2 and Grade 3 achievable (Ajax, Pyronix, Hikvision Ax Pro); battery life 2–5 years; jamming detection via missed heartbeats; Grade 4 not achievable wirelessly; short supervision intervals improve jamming detection