Eaton Magnum DS low-voltage switchgear and breakers
Manufacturer: Eaton
Eaton Magnum DS, the UL 1558 workhorse whose draw-out breakers anchor the priced US used market
This model is part of SecondWatt’s switchgear research catalogue. Specifications and price observations are included where supported by sources. Equipment availability and commercial terms require confirmation.
Eaton Magnum DS dossier: UL 1558 switchgear to 10,000 A bus with breakers priced 7,500-21,665 USD by condition, PXR retrofits, inspection checklist.
Magnum DS is Eaton's low-voltage metal-enclosed switchgear platform (UL 1558) built around Magnum DS draw-out air power circuit breakers, sold today alongside the next-generation Magnum PXR platform that builds on the same foundation. Ratings: 600 V class, main bus 1,600-10,000 A, breakers to 6,000 A, short-circuit withstand published to 200 kA (rear-access) with 30-cycle short-time, silver-plated copper bus, ANSI/IEEE C37.20.1, C37.51, UL 1558, UL 1066, and CSA C22.2 No. 31, in 18-60 inch sections; the arc-resistant front-access variant tests to IEEE C37.20.7 at up to 85 kA.
The trade still calls it Cutler-Hammer, and the breakers are the liquid asset: a reconditioned MDS-C08 at 16,665 USD (21,665 in 'Plus' trim), an unused MDS616 1,600 A at 12,000 USD, an MDS608 refurbished at 7,500 USD, and MDS620 2,000 A units at 15,500 USD unused versus 7,500 USD tested, all with test reports.
The OEM-sanctioned PXR trip-unit retrofit (with optional motorized remote racking) keeps 20-year lineups serviceable, which is precisely what sustains those used-breaker values.
Why it matters
Magnum DS is the deepest priced bench in ANSI LV switchgear: six live price points across conditions on one breaker family, a 2.1x gray-over-refurbished premium visible on the same frame, and an OEM retrofit path that extends asset life.
Who buys it
Owners of Magnum DS lineups across data centers, hospitals, and industry buy breakers and spares continuously; contractors buy tested units against 54-week LV switchgear leads; modernizers buy PXR retrofits instead of new lineups. The documented failure mode (mechanism retaining spring causing trip-free on close) is a known inspection item.
Role in the data center
Low-voltage distribution switchgear and draw-out mains and feeders sitting behind unit substations, feeding UPS input, UPS output and mechanical boards at 600 V class. Two decades of installs mean the spares-and-retrofit economics, not new-lineup pricing, define maintenance planning on most of this fleet.
Key specifications
| Main bus range | 1,600-10,000 A |
|---|---|
| Breaker ceiling | 6,000 A |
| Withstand (rear-access) | 200 kA |
| Arc-resistant variant | 85 kA (IEEE C37.20.7) |
| Standards | C37.20.1, C37.51, UL 1558, UL 1066 |
| Observed MDS-C08 recon | 16,665 / 21,665 ('Plus') USD |
| Observed MDS620 | 15,500 unused / 7,500 tested USD |
| Observed MDS616 unused | 12,000 USD OBO |
| Observed MDS608 refurb | 7,500 USD OBO |
| Retrofit path | Magnum PXR trip units + MR2 remote racking |
Technical summary
Voltage class: 600 V. Main bus: 1,600-10,000 A; breakers to 6,000 A. Short-circuit withstand: to 200 kA (rear-access); 85 kA arc-resistant variant. Short-time: 30-cycle. Standards: ANSI/IEEE C37.20.1, C37.51; UL 1558, UL 1066; CSA C22.2 No. 31. Arc-resistant: IEEE C37.20.7 (front-access variant). Sections: 18-60 in W x 54-90 in D x 96 in H. Trip units: Digitrip (legacy) to PXR (retrofit/current). Seismic: IBC/CBC/UBC Zone 4.
Major variations
Three switchgear constructions: rear-access standard, front-access, and front-access arc-resistant tested to IEEE C37.20.7 at up to 85 kA, in sections from 18 to 60 inches wide. Within the Magnum family, Magnum DS carries UL 1558 switchgear duty, Magnum SB is the insulated-case breaker for UL 891 switchboards, and Magnum PXR is the current platform built on the same foundation. Trip-unit generation is the other axis buyers price on: Digitrip 520 and 1150 units on legacy breakers versus OEM PXR retrofits on modernized ones.
Configurations and options
Three constructions carry different prices and different arc-flash positions: rear-access standard, front-access, and front-access arc-resistant tested to IEEE C37.20.7 at up to 85 kA, against a 200 kA withstand published for the rear-access build. Section width runs 18-60 inches and the main bus 1,600-10,000 A with breakers to 6,000 A, so bus rating and section count drive lineup price. On the breakers, the order variables are frame size, interrupting rating, manual or electrical operation, and trip-unit generation, Digitrip 520 or 1150 on legacy units against an OEM PXR retrofit on modernised ones. Optional MR2 motorised remote racking fits any Magnum PXR draw-out breaker.
Compatibility and dependencies
Breakers and cells are matched: a Magnum DS breaker seats in its own cassette, and Magnum SB, the insulated-case breaker built for UL 891 switchboards, is a different product with a different application listing. Standards are ANSI/IEEE C37.20.1 and C37.51 with UL 1558, UL 1066 and CSA C22.2 No. 31, so the lineup is 600 V class and its withstand rating has to be coordinated with the available fault current from the upstream transformer and any paralleled generation. Sections are 18-60 inches wide, 54-90 inches deep and 96 inches high, and rear-access construction needs the rear working space the standard build assumes. Seismic qualification is published to IBC, CBC and UBC Zone 4. Digitrip units are verified by secondary injection using Eaton's MTK2000 kit.
Pricing and availability
Published price range: $7,500 - $21,665. Trend: rising Breakers are up 47% since 2021 category-wide, and Magnum DS shows the structure: refurbished frames hold 7,500-16,665 USD, unused surplus commands a roughly 2.1x premium over tested-used on the same frame (MDS620: 15,500 versus 7,500 USD), and 'Plus'-tier reconditioning adds 30% over standard. The PXR retrofit path supports the floor. Lead time, new: 54 weeks (LV switchgear class). Lead time, used or refurbished: 1-4 weeks (deep dealer stock). Warranty, used: 1-year typical from reconditioning dealers.
Lifecycle and maintenance
LV power circuit breakers serve 30-40 years on 3-5 year maintenance cycles per ANSI/NETA MTS and NFPA 70B, with mechanism lubrication and injection testing the critical items. A deep reconditioning ecosystem (Relectric, NAS, Bay Power, Bullock) tests to NETA specifications and warrants units for 1 year. OEM trip-unit retrofit programs (Eaton PXR, ABB EntelliGuard R, Siemens 3WA retrofit) extend installed platforms past electronics obsolescence, which sustains used-breaker values.
Thermal and emissions profile
Switchgear produces no combustion emissions; the regulatory profile is electrical safety and materials. NFPA 70B became a standard in its 2023 edition, making maintenance programs mandatory rather than recommended, and arc-flash rules (NFPA 70E) govern work practices. LV air-insulated gear carries no F-gas exposure, and construction standards (UL 891, UL 1558, IEEE C37.20.1) plus arc-resistant options under IEEE C37.20.7 define the safety envelope buyers should verify.
Common failure points
- Mechanism springs and lubrication — Slow trips, trip-free on close, failure to latch on aged units
- Trip unit electronics — Nuisance trips or no-trip from aged or obsolete electronics
- Contacts and arc chutes — Overheating and interruption failure from eroded contacts or cracked chutes
- Secondary wiring — Control faults from damaged secondary disconnects and aux switches
- Provenance and counterfeits — Counterfeit or mis-labeled breakers fail catastrophically under fault
- Cassette and racking wear — Misalignment and cluster contact damage on worn cradles
Inspection checklist
Mechanism: exercise open/close 10+ cycles; verify the charge/close/trip sequence completes and the mechanism latches on every close; treat any failure to latch on close as a finding and check it against the OEM acceptance procedure. Trip curve: primary injection test; NETA field data shows 22% of LV power breakers off their published curves. Secondary injection: verify all 4 protection functions (LSIG) against settings; record as-found/as-left values. Contact resistance: micro-ohm test each pole; investigate readings above 1.5x sister poles. Insulation resistance: megger at 1,000 V per ANSI/NETA MTS acceptance tables. Contact wear: inspect arcing contacts and wear indicators against the OEM replacement limit. Arc chutes: remove and inspect for cracks, erosion, and metal splatter; replace damaged chutes. Lubrication: verify mechanism grease condition; dried lubricant is the leading slow-trip cause on 20+ year units. Racking: exercise draw-out mechanism through connect/test/disconnect; verify shutter operation.
Procurement channels
Relectric (priced recon), NAS/eBay (priced unused and tested), BCS, Circuit Breaker Sales NE, and Quality Switchgear (208 Magnum items, quote-only); whole 3-section lineups appear on eBay. Digitrip secondary-injection kits (MTK2000) support acceptance testing.
Regional notes
A North American 600 V product listed to UL 1558 and UL 1066 with CSA C22.2 No. 31, built for 60 Hz ANSI practice, with no IEC counterpart to import: an IEC 60947-2 air circuit breaker is not a substitute in a UL 1558 lineup. Seismic qualification is stated to IBC, CBC and UBC Zone 4, which is what a California or Pacific Northwest project will be asked to evidence. Eaton, Cutler-Hammer and Westinghouse all appear on dealer listings for the same hardware because of the brand chain rather than because they are different products.