How to choose a UPS for your router, NVR, and office rack

A power cut of a few seconds can reset the router, interrupt calls, leave cameras without recording, and corrupt NVR data. A UPS—also known as an Uninterruptible Power Supply—powers devices for a limited time and filters out certain electrical disturbances. Choosing one based solely on the VA number on the box can lead to errors: you must check the actual wattage, runtime, output type, and connectors.

The goal is not always to work for an hour without network. In a small office, it may be enough to overcome micro-outages and have ten or fifteen minutes to save, shut down, or maintain communications. In video surveillance, it is important that the router, PoE switch, and NVR continue to operate together; protecting only one breaks the chain.

VA and W: both figures matter

VA expresses apparent power and W expresses active power. Devices consume watts, and the UPS has a limit for both values. A 700 VA model can deliver, for example, 360 W; you should not connect 600 W just because the first number is 700.

Add up the power of the devices that will remain on battery. Use actual measurements if possible, or the technical specifications as a conservative estimate. Then apply a 20–30% margin. Avoid working permanently at 100%: it reduces battery life and leaves little room for peaks or expansions.

PoE consumption must include the power delivered to cameras or access points, not just the switch's electronics.

How to estimate runtime

Runtime is not directly derived from VA. It depends on the battery, efficiency, age, temperature, and load. A UPS can power 50 W for much longer than 300 W. Consult the manufacturer's runtime curve for the expected load percentage.

If you need ten minutes at 200 W, look for that point on the curve, not the advertised "up to X minutes" runtime, which is usually measured with a specific load. The battery loses capacity over the years; design with a margin and test the system periodically.

Which topology to choose

Standby or offline: suitable for simple loads and limited budgets. Switches to battery when a problem is detected.

Line-interactive: adds automatic voltage regulation and is often a good option for routers, switches, NVRs, and office workstations.

Online double-conversion: continuously delivers regenerated power and offers greater isolation, at the cost of higher price, heat, and consumption. Used for critical loads or demanding electrical environments.

For a small setup with moderate consumption, a 700 VA, 360 W Salicru line-interactive UPS may be sufficient if the calculated total and runtime match. If you need more margin and four outputs, the 1100 VA, 600 W Salicru UPS can handle a larger load; do not assume that this guarantees a specific runtime without reviewing the curve.

Which devices to connect and which not to

Prioritize ONT, router, firewall, switch, main access point, NVR, and a management device if essential. Do not connect laser printers, heaters, coffee makers, or loads with high peaks unless the UPS is designed for it. A laser printer can trigger an overload when heating the fuser.

If the switch powers PoE cameras, maintaining the NVR and router but not the switch stops camera recording. Similarly, protecting the switch without the ONT or router preserves the local network, but not the Internet. Define what service you want to maintain and protect all its links.

Schuko or IEC outputs

Physically check the UPS outlets. Some models offer Schuko; others, IEC C13. There may also be surge-protected outlets that do not receive battery power. Label them to avoid connecting the NVR to the wrong outlet.

In the collection of power cables and adapters, you can find suitable IEC and Schuko cables. Avoid daisy-chaining power strips without evaluating power, grounding, and secure fastening. In a rack, organize cables so that an intervention does not accidentally disconnect critical power.

Example calculation for video surveillance

Assume a 30 W NVR, 25 W router and ONT, and a PoE switch that consumes 20 W plus four 8 W cameras. Total: 107 W. With a 25% margin, design for at least 134 W. Both UPS models mentioned could in principle support that power, but the decision between them will depend on the minutes needed, number of outlets, and growth.

If you plan to double the number of cameras, calculate for the future: four additional cameras at 8 W would add 32 W, plus possible losses. Also check the switch's PoE budget. Runtime must be tested with all devices on, recording, and transmitting.

Installation and maintenance

Place the UPS in a well-ventilated area, away from moisture and heat sources. Do not cover vents or enclose it in a rack without circulation. Allow the battery to charge according to the instructions before the initial test.

Perform a controlled test: record the time, displayed load, and duration until the planned threshold, without unnecessarily draining the battery. Configure an orderly shutdown via USB or network when the UPS and NVR/server allow it. Note the installation and replacement dates; a battery that maintains voltage when idle can drop quickly under load.

Purchase checklist

• Measured or estimated watts of each device.
• UPS limit in both W and VA.
• Runtime on the curve for that load.
• 20–30% margin and planned expansions.
• Number and type of battery-backed outlets.
• Topology: standby, line-interactive, or online.
• Waveform and source compatibility.
• USB/network communication and automatic shutdown.
• Access for battery replacement.
• Ventilation, noise, and dimensions.

You can compare models in the UPS collection. For a professional rack, prepare a list of loads and the target time before asking for advice.

Common mistakes

Sizing only by VA. The watt limit can be reached sooner.

Connecting a full power strip without inventory. Someone might add an unplanned load months later.

Forgetting PoE cameras. Their consumption comes from the switch and counts towards the UPS.

Not testing actual runtime. The battery ages, and loads change.

Seeking an hour of runtime with a small UPS. Sometimes it is better to shut down orderly or use a higher-capacity solution.

Frequently asked questions

Is a 700 VA UPS suitable for a router and an NVR?

It can be suitable if the load is below its W limit and the curve offers the desired runtime. Add up all the devices.

Should I also connect the fiber ONT?

Yes, if you want to maintain Internet. Protecting only the router does not power the operator's optical termination.

How long does a UPS battery last?

It depends on temperature, cycles, and quality. Check capacity periodically and follow the manufacturer's recommended interval.

Can I connect a laser printer?

It is not usually recommended on battery-backed outlets due to its consumption peaks, unless specifically sized and approved.

Does a UPS replace a backup?

No. It provides temporary power and can facilitate a safe shutdown, but it does not protect data against deletion, theft, or logical failure.