I manage purchasing for a 240-person logistics site. I don't design electrical systems, but I've approved roughly $180,000 in power-protection spend since 2019: Eaton UPS units, batteries, surge protectors, transfer switches, and the labor to install everything. This is the checklist I use when someone says we need one of those UPS boxes and we have to budget it correctly the first time.
It's not a guide for a Tier IV data center. That's a different engineering world. My experience is with server closets, edge rooms, and small industrial control loads that need to stay online through short power events. If your environment is different, use this as a discussion starter, not the final spec.
Start with a load list, not a general sense of the IT room. Write down every device in the protected path: switch, server, firewall, phone system, security panel, modem. If you can, measure actual current with a clamp meter. If you can't, use nameplate amps and add a 20 percent safety buffer.
A lot of UPS spec sheets are in VA, not watts. VA is not equal to watts. A 1,500 VA unit might only supply about 900 W or 1,200 W, depending on the power factor. When a vendor quotes a 10 kVA UPS, ask for the kW rating at your load power factor. If they don't know, you aren't ready to compare models yet.
I learned this after I assumed the VA number was the wattage. It wasn't. The spec sheet was not wrong; my assumption was.
Also write down the runtime you need. If you need twenty minutes to shut down in an orderly way, a normal UPS runtime chart handles it. If you need two hours, budget for a battery cabinet before you choose the UPS frame.
Search results use the phrase UPS battery backup and surge protector because many small products combine both functions. But they are not the same thing.
A surge protector clamps voltage spikes. It does not supply power when the grid stops. A UPS battery backup supplies power for a limited runtime after an outage starts. If a utility surge hits the building, a small UPS may absorb damage unless there is upstream surge protection. For a facility-level view, install a listed surge protective device at the panel and use the Eaton UPS for ride-through and clean power.
The word and on a spec sheet does not mean one product solves every risk. It means both circuits are in one consumer box. That works for a small network stack. It does not replace panel-level protection.
The UPS is the box. The batteries are the part you will replace. If you only compare list prices, you will miss the largest maintenance cost in the first ten years.
Ask the vendor to send a quote line for the exact battery part number, expected design life, and installed replacement cost. For a large UPS, battery cabinets may be separate from the main unit. The main UPS quote might not include the DC disconnect, cables, installation labor, or disposal of old cells.
I compare Eaton UPS batteries against aftermarket options. To be fair, aftermarket is often cheaper. But we have learned that warranty investigations get messy when a replacement part is not authorized. We now use Eaton battery packs and set aside money for replacement in years four through six. That is a total cost decision, not a first-invoice decision.
Nobody reads the manual until an alarm goes off. With a three-phase UPS, that order is too late.
Download the Eaton 93PM UPS manual and send the PDF to the project electrician before they arrive. The manual includes clearance distances, torque values, cable entry requirements, operating temperatures, and the proper steps to isolate the UPS. This documentation should shape the shop drawing.
We almost mounted a three-phase UPS with six inches of clearance in the back. The manual said it needed more, and the extra clearance also allowed technicians to get behind the unit for service. Checking the manual before fabrication saved us a change order and probably some colorful language on install day. For other products, find the manual for the exact model number. Each family has its own requirements.
UPS batteries are not sized to run for days. If you need long-term backup, a generator is part of the picture. That leads to the generator interlock vs transfer switch question.
A generator interlock is a mechanical plate on the panel. It stops the main breaker and generator breaker from being switched on at the same time. It is simple and cheaper, but it relies on a person. Someone has to walk to the panel, open the main, start the generator, and close the generator breaker.
A transfer switch does the source selection in a controlled way. A manual transfer switch still uses a human, but it is designed for the job. An automatic transfer switch senses the outage, starts the generator, and transfers the load by itself. It costs more. If nobody is on site at 2 AM, an ATS is usually the correct operating cost.
Local codes matter. In commercial installations, the National Electrical Code places conditions on optional standby systems. Have a licensed electrician check whether an interlock is even allowed, and get the drawings reviewed before ordering hardware. Also budget for the generator's own starter battery and charger. A UPS can ride through the first few seconds, but it cannot start a generator with a dead battery.
The biggest procurement mistake is comparing only the delivered price of the UPS. I use one spreadsheet for every quote. The columns are UPS, battery cabinet, DC disconnect, cabling, surge protection, transfer switch, generator connection, installation labor, commissioning, remote monitoring, battery disposal, and projected battery replacement.
I compare total cost after adding all line items. When a quote is vague, I use the high end of the range and add 10 percent. I have been burned enough by the phrase that is extra to make it a standard question early in the conversation.
My standard follow-up after any vendor presentation is: What is not included? The vendor that lists all fees upfront, even when the total looks higher, is usually the one that costs the least in the end.
Give yourself enough lead time. Battery lead times and electrician schedules are real constraints. Start with the manual, then settle the generator transfer question, then compare quotes on the same spreadsheet. That order has saved me more than any last-minute discount.
I should add that this checklist is not a substitute for stamped electrical drawings. On every large UPS project, the engineer's review caught something I would have missed. Use the cost process to force the technical review into the timeline, not after it.