How many cameras can one PoE switch really support?
Rated port count does not equal real-world capacity. A 24-port PoE+ switch (370W budget) typically supports 10–14 high-powered cameras, not 24. Learn why PoE switches fail before rated count and plan injectors or additional switches accordingly.
What size UPS do I need for my surveillance system?
Calculate total watts of all equipment (NVR, switch, access control, intercoms) and multiply by 1.2 for safety. A 1000W device requires a 1.2kVA UPS minimum. For 30–60 minute hold-up, add battery packs. Consult the UPS datasheet runtime table for your exact load.
Can I run cameras over long cable distances without power loss?
Beyond 100 meters, voltage drop becomes significant. Use thicker cable (e.g., 10/2 instead of 18/2) or deploy a midspan PoE injector at the halfway point. Test actual voltage at the camera before and during operation to confirm it meets the minimum 11.5V for PoE devices.
Should I use surge protection outdoors?
Yes. Outdoor camera runs, especially on poles or towers, attract lightning transients that destroy unprotected equipment. Install a surge-suppression cartridge or dedicated SPD (Surge Protective Device) at the camera supply entry point.
What's the difference between 12V and 24V supplies?
24V systems have lower current for the same power, so they suffer less voltage drop over distance and are preferred for long cable runs and industrial deployments. 12V is common in legacy and compact camera designs. Choose based on your camera specs, not preference; mixing standards requires careful supply sizing and testing.
How often should I test my UPS battery backup?
Test battery runtime (load test) at least quarterly, or annually if the UPS is older. Monitor battery age; most UPS batteries degrade after 3–5 years and should be replaced proactively. For critical facilities, use a monitored UPS with email alerts for battery health.