20 kVA 208/120 V Three-Phase Online UPS Comparison
Compact three-phase UPS systems are widely deployed in healthcare, education, retail, and distributed IT environments requiring robust online power protection, efficient operation, and manageable installation footprint. The Xtreme Power E91 20 kVA and Eaton 9355 20 kVA are true online double-conversion UPS systems designed for 208/120 V three-phase applications.
Both platforms provide high-quality double-conversion power protection and integrated maintenance bypass capability. However, differences emerge in usable real-power output, operating efficiency, cabinet footprint, system weight, and standard ownership coverage.
The E91 20 kVA delivers full 20 kW output at unity power factor, higher operating efficiency, and dramatically smaller and lighter physical design. The Eaton 9355 provides longer internal runtime but achieves this with substantially larger size and weight and reduced usable output at 18 kW.
For facilities prioritizing maximum usable capacity, compact footprint, and simplified installation, the E91 20 kVA provides a more space-efficient and ownership-optimized solution.
Learn more about the Xtreme Power E91 Series
https://xpcc.com/products/e91/
Key Differentiators at a Glance
- Full 20 kVA / 20 kW usable output (unity power factor)
• Higher operating efficiency
• Dramatically smaller cabinet footprint
• Significantly lighter system weight
• Full rated-load runtime capability
• Factory start-up included as standard
• Longer standard electronics warranty
20 kVA Three-Phase UPS Feature Comparison
208/120 V Applications
| Feature | Xtreme Power E91 20 kVA | Eaton 9355 20 kVA | Notes / Considerations |
| Rated Capacity | 20 kVA / 20 kW | 20 kVA / 18 kW | Full real-power output (unity PF) |
| Output Power Factor | 1.0 | 0.9 | More usable kW from same kVA |
| UPS Topology | Online double conversion | Online double conversion | Comparable protection architecture |
| Efficiency (Online) | 94% | 91% | Higher efficiency reduces energy and cooling |
| Maintenance Bypass | Standard (integrated) | Standard (integrated) | Both allow servicing without downtime |
| Dimensions (H × W × D) | 40.2 × 12.3 × 34.0 in | 66.0 × 20.0 × 34.1 in | Dramatically smaller footprint |
| Weight (with batteries) | 570 lb | 1,160 lb | Substantially lighter system |
| Internal Runtime | 7 min @ 20 kW | 18 min @ 18 kW | Eaton runtime requires much larger chassis |
| Runtime Expansion | External battery cabinets | External battery cabinets | Comparable scalability |
| Warranty (Electronics) | 2 years | 1 year parts | Longer standard coverage |
| Start-up & Labor | Factory start-up included | Start-up optional; 90-day labor | Lower deployment cost |
| TAA Compliance | TAA compliant | TAA compliant | Eligible for federal procurement |
Download the Printable Comparison
Download the Xtreme Power E91 20 kVA vs Eaton 9355 comparison PDF
Ideal for engineering submittals, bid reviews, and procurement evaluations.
https://xpcc.com/wp-content/uploads/Xtreme-E91-20k-Eaton-9355-Comparison.pdf
Where the E91 20 kVA Excels
- Facilities requiring full 20 kW usable output
• Installations with limited floor or vertical space
• Deployments requiring lighter equipment placement
• Projects seeking higher operating efficiency
• Applications requiring compact three-phase UPS footprint
• Specifications requiring longer electronics warranty
• Federal projects requiring TAA compliance
When the Eaton 9355 May Be a Fit
- Facilities standardized on Eaton infrastructure
• Installations prioritizing maximum internal runtime
• Sites aligned with existing 9355 deployments
• Locations where larger cabinet footprint is acceptable
Who Should Choose Which?
Choose the Xtreme Power E91 20 kVA if you need:
- Full 20 kW usable capacity
• Smaller and lighter UPS footprint
• Higher operating efficiency
• Full-load runtime capability
• Factory start-up included
• Longer standard electronics warranty
Choose the Eaton 9355 if you need:
- Longer internal runtime in base cabinet
• Alignment with existing Eaton deployments
• Standardization with 9355 infrastructure
Compare E91 20 kVA to Other Compact 3-Phase UPS Alternatives
Evaluating compact three-phase UPS platforms or planning multi-site standardization?
View all E91 Series comparisons:
https://xpcc.com/e91-ups-comparisons/
Plan With Confidence
Xtreme Power Conversion supports specification development, runtime planning, and three-phase UPS deployment for healthcare, education, retail, and distributed IT environments.
(800) 582-4524
sales@xpcc.com