Six physical servers, 35 virtual servers and 12 switches set the continuity requirement
Eaton’s Central Catholic High School case documents two 9355 units and a later 93E supporting six physical servers, 35 virtual servers and 12 switches. Equipment record: Eaton 93E, companion identifier Eaton 9355. Decision: Use the 93E and paired 9355 architecture as a generator bridge and graceful-shutdown layer, with runtime and monitoring verified against the actual server and switch load.
From utility loss to generator pickup
The school network combined a centralized 93E with two earlier 9355 units. The UPS role was not long-duration generation. It was to carry the network through the interval before generator supply stabilized and to preserve enough controlled time for shutdown if generation did not arrive. Remote monitoring connected the power event to the virtual-server shutdown decision.
For Eaton 93E, the applicability boundary is anchored to 6 physical servers, 35 virtual servers and part Eaton 9355. The 3 worked inputs remain assumptions until they are recorded at the equipment.
Confirm availability and catalogue details for Eaton 93E or Eaton 9355 on the UPS selection and battery help centre page.
Figure 1. Eaton 93E equipment and power path
Three UPS positions and 53 protected assets
The controlling numerical record is: Physical server count: 6 physical servers; Virtual server count: 35 virtual servers; Switch count: 12 network switches; 93E plus two 9355 units: 3 UPS positions; Worked distribution reference: 208 V; Published 93E efficiency point: 98 %; Worked generator-pickup allowance: 90 s; Worked shutdown reserve: 300 s. Each value has a defined source or assumption status in the engineering ledger. Values from different configurations are not combined as though they came from one installed system.
| Engineering parameter | Value | Evidence status |
|---|---|---|
| Physical server count | 6 physical servers | Published OEM value |
| Virtual server count | 35 virtual servers | Published OEM value |
| Switch count | 12 network switches | Published OEM value |
| 93E plus two 9355 units | 3 UPS positions | Published OEM value |
| Worked distribution reference | 208 V | Worked design assumption |
| Published 93E efficiency point | 98 % | Published OEM value |
| Worked generator-pickup allowance | 90 s | Worked design assumption |
| Worked shutdown reserve | 300 s | Worked design assumption |
The 53 protected compute and network items are not interchangeable loads, and the published case does not provide their watts. Runtime therefore cannot be reconstructed from asset count. The worked timing budget uses explicit assumptions only to show how generator pickup, stabilization and shutdown reserve would be checked during a site test.
Counting the bridge interval
The worked check uses required bridge time = generator allowance + shutdown reserve. With a 90-second generator allowance and a 300-second shutdown reserve, the result is 390 seconds, or 6.5 minutes. A battery test would need to demonstrate the site-approved interval at the measured load, not merely confirm that the UPS passes self-test. The arithmetic is reproducible, but it remains a design check until the listed inputs are confirmed at the equipment.
The 390 seconds, or 6.5 minutes result follows from required bridge time = generator allowance + shutdown reserve. If the 208 V input changes, this check is repeated rather than carrying the earlier result into a different operating state.
Figure 2. Quantified basis for the Eaton 93E decision
Why monitoring mattered to the power path
The two 9355 units and the 93E created separate failure domains. A single aggregate runtime value would hide which server, switch or storage path depends on each unit. The asset map must connect every protected load to one UPS output and one shutdown sequence.
Generator pickup is not complete when the engine starts. Voltage and frequency must be accepted by the relevant UPS, the rectifier must remain stable and recharge current must not destabilize the source. The event log should show the change from battery to accepted generator input without an unintended bypass transfer.
Remote monitoring supplies the time stamps needed to distinguish a short utility interruption from a failed generator bridge. It also gives the virtualization platform a defined trigger. Shutdown authority stays disabled until the ordered stop sequence, restart dependency and abort condition are proven.
| Path | Technical consequence | Disposition |
|---|---|---|
| Apply the stated engineering decision | Use the 93E and paired 9355 architecture as a generator bridge and graceful-shutdown layer, with runtime and monitoring verified against the actual server and switch load. | Selected basis |
| Generic model substitution | Select by family name or rating alone, without confirming the exact configuration. | Not selected on the stated evidence |
| Unverified operating assumption | Treat a design assumption as though it were a site measurement. | Reconsider only if the input changes |
Confirm availability and catalogue details for Eaton 93E or Eaton 9355 on the UPS system catalogue page.
Confirm availability and catalogue details for Eaton 93E or Eaton 9355 on the catalogue of UPS replacement batteries page.
The Eaton 93E decision retains part Eaton 9355, the 390 seconds, or 6.5 minutes calculation result and the manufacturer-published 6 physical servers point in one equipment record. Applicable OEM instructions, qualified electrical authority and the installed single-line or wiring record remain controlling for any executable work.
Generator and shutdown proving test
Acceptance of Eaton 93E depends on five recorded checks:
- Map each physical server, virtual host and network switch to its supplying UPS.
- Measure load on the 93E and both 9355 units before the test.
- Record utility loss, generator start, accepted input and battery-to-line transitions on one timeline.
- Prove the 390-second worked budget or replace it with the approved measured interval.
- Run an observed graceful-shutdown test without relying on an unverified software countdown.
The Eaton 93E record is not accepted if part Eaton 9355 does not match, the calculation does not reproduce 390 seconds, or 6.5 minutes, or the final operating state is not recorded. The equipment returns to the approved safe state when a check stops, and the unresolved condition remains open without an invented repair result.
Figure 3. Verification sequence for Eaton 93E
The architecture succeeds only as a complete chain
The published school case supports a layered generator-bridge architecture, not a claim that any three UPS units automatically create redundancy. The usable result depends on measured load, generator acceptance, battery condition, monitoring and the shutdown dependency map.
GDF’s UPS service page covers field measurements and service work for Eaton 93E.
Decision rule: Use the 93E and paired 9355 architecture as a generator bridge and graceful-shutdown layer, with runtime and monitoring verified against the actual server and switch load. A different model, load, voltage, battery string, software version or operating state requires a new check against the applicable manufacturer record.
Sources
- Eaton Central Catholic High School success story
- Eaton 93E product family record
- Eaton 9355 product family record
- GDF Technologies, internal engineering reference: DataCenter/Three-Phase and Data Center Power.md
- GDF Technologies, anonymized field-case library, used only where the text identifies a retained field fact.