We're building a new facility and have updated the electrical plan to provide two dedicated rack circuits: one 208V/240V circuit and one 120V 30A circuit. The MDF will contain four UniFi Pro 48 PoE switches supporting roughly 26 cameras, seven access points, and 20 desk phones; two UDM Max firewalls in an HA pair; a dual-CPU Dell server with redundant 600W power supplies; a UniFi Enterprise NVR with redundant power supplies and approximately 450W maximum draw; two internet modems; and miscellaneous equipment.
The original plan involved mixing 208V and 120V power between redundant supplies, but after further research and feedback, I'm changing the design to use two APC SRT3000RMXLT-NC UPS units. One will use a 120V transformer so the setup can support the required equipment while keeping both UPS systems based on the same model and input voltage. One UPS will carry the primary loads, while the other will provide independent power for redundant server and NVR supplies and other equipment.
The calculated maximum load is close to the capacity of a 3000VA unit only if every PoE port and device draws its absolute maximum simultaneously. Actual usage should be much lower, with roughly 40–50 powered PoE devices and typical rack load well below the theoretical maximum. The refurbished UPS units, including new batteries, cost less than $4,500 compared with an estimated $10,000–$12,000 for a comparable new setup.
Does this dual-UPS approach provide reasonable capacity and redundancy? Would you change anything while staying near the same budget?
3 Answers
Using two UPS units with the same 208V-based design is a better approach than splitting redundant power supplies across different voltages. If possible, feed appropriately rated PDUs from each UPS so equipment can remain powered if one UPS fails. Just make sure every device and PDU is compatible with the actual output voltage and plug types.
A UPS battery plan matters as much as the initial purchase. Even lightly used batteries age, so follow a fixed replacement schedule—around three years is a reasonable conservative interval for these units. Also consider configuring automatic shutdown for nonessential services so the server and core network can remain online longer during an extended outage.
It may be worth reviewing why four 48-port switches are required if only around 50 devices are currently expected. They could be justified by PoE capacity, layout, uplinks, expansion, or avoiding a difficult recabling project later, but documenting the expected growth and equipment lifetime will help confirm that the rack design is appropriately sized.
That was my conclusion as well. I’m changing the plan to two SRT3000RMXLT-NC units, with a transformer on one of them, rather than mixing UPS voltages between redundant power supplies.