PoE budget
Use each device's maximum power from its datasheet (IR and heater on).
Columns: device · quantity · watts each
Device load:
Required with margin:
CCTV storage and bandwidth
Size for night-time bitrate: noisy low-light scenes can double it.
Per camera per day:
Recording bandwidth: (more than a 1 Gbps uplink should carry)
Usable storage needed:
RAID 6 with n disks of size S gives (n − 2) × S usable.
Pixel density (DORI)
IEC 62676-4 targets: identify 250, recognise 125, observe 62, detect 25 px/m.
px/m:
Maximum scene width for this camera: identify , recognise , observe .
Fire alarm standby battery
Ah = (standby A × standby h + alarm A × alarm h) × safety factor.
Required:
Next standard size: (two 12 V batteries in series for a 24 V panel)
Beyond common sizes. Split the load or use an external power supply.
100 V line PA amplifier
Add up the speaker tap settings for the zone.
Columns: speaker type · quantity · tap (W)
Total tap load:
Amplifier channel: at least
Expected line impedance: . Check it with an impedance meter before connecting.
Fibre loss budget
Maximum acceptable loss using TIA-568.3 component values.
Fibre + connectors + splices dB
Loss budget:
A measured loss above this fails. Well-installed links usually measure well below it.
Voice bandwidth (SIP trunk / WAN)
Ethernet bandwidth per direction at 20 ms packetisation.
Needed in each direction:
Check the upload speed of the internet link. It is usually the limiting direction.