E91 10 kVA vs Eaton 9355
The Xtreme Power E91 10 kVA and the Eaton 9355 10 kVA are online double-conversion UPS systems for 208/120V three-phase applications. The E91 delivers full-rated 10 kW output at unity power factor, higher operating efficiency, longer usable runtime at matched load, and a significantly smaller, lighter chassis; the Eaton 9355 provides comparable topology with reduced usable output at 9 kW in a larger, heavier cabinet.
Where the E91 10 kVA leads
- Full 10 kVA / 10 kW usable output at unity power factor — vs the Eaton’s 9 kW.
- Higher operating efficiency (93% vs 91% online).
- A significantly smaller footprint and lighter weight (315 vs 373 lb).
- Longer usable runtime at higher real load.
- Factory start-up included as standard, plus a longer standard electronics warranty.
10 kVA three-phase UPS, side by side
| Specification | Xtreme Power E91 10 kVA | Eaton 9355 10 kVA | Advantage |
|---|---|---|---|
| Rated capacity | 10 kVA / 10 kW | 10 kVA / 9 kW | Full usable output, unity PF |
| UPS topology | Online double-conversion | Online double-conversion | Comparable premium protection |
| Efficiency (online) | 93% | 91% | Higher efficiency, less cooling |
| Maintenance bypass | Standard (integrated) | Standard (integrated) | Both integrated |
| Size (W × D × H) | 9.9 × 26.3 × 32.3 in | 12 × 33.5 × 32.2 in | Significantly smaller footprint |
| Weight (with battery) | 315 lb | 373 lb | Lighter system |
| Internal runtime | 11 min @ 10 kW | 8 min @ 9 kW | More usable runtime at higher real load |
| 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 | More comprehensive standard coverage |
| TAA compliance | TAA compliant | TAA compliant | Eligible for federal procurement |
Both are true online double-conversion three-phase UPS with integrated maintenance bypass and TAA eligibility. The E91 delivers full 10 kW usable output (vs 9 kW), higher efficiency, longer usable runtime, a smaller and lighter chassis, factory start-up, and a longer standard warranty. Confirm Eaton 9355 specifications against current Eaton documentation.
Choosing between them
Both deliver premium online protection, so the decision turns on usable capacity, footprint, efficiency, and ownership. Choose the E91 for full 10 kW usable output, a smaller/lighter cabinet, higher efficiency, factory start-up, and longer warranty; the 9355 fits where an existing Eaton standard governs.
Choose the E91 10 kVA if you need
- Full 10 kW usable capacity
- A smaller, lighter UPS footprint
- Higher operating efficiency
- Longer internal runtime at load
- Factory start-up included
- Longer standard electronics warranty
The 9355 10 kVA may fit if you need
- Facilities standardized on Eaton infrastructure
- Alignment with existing 9355 deployments
- Eaton service ecosystem continuity
Related comparisons
Standardizing compact three-phase UPS across your facilities?
Xtreme Power supports E91 three-phase UPS sizing, runtime planning with external battery cabinets, modernization strategy for legacy three-phase UPS, and TAA-compliant procurement for healthcare, education, retail, industrial, and enterprise infrastructure.