Avtron 8850

30 ft medium voltage container load bank to 5,000 kVA at 0.8 pf, which is 4,000 kW, at 690 V to 24 kV

Avtron 8850 is one of 16 load banks tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.

Avtron 8850 medium voltage container load bank, up to 5,000 kVA at 0.8 pf, 690 V to 24 kV, 30 ft ISO. Transformer, siting limits and inspection points.

The Avtron 8850 is a resistive-reactive load bank rated in kVA at 0.8 power factor, in a 30 ft ISO style container, with an oil-filled step-down transformer built in so the unit connects directly at medium voltage. Avtron publishes 690 to 24,000 V on the pub 5123 rev A data sheet and 3.3 kV to 24 kV in the March 2026 international data centre brochure. At 5,000 kVA and 0.8 pf that is 4,000 kW of real load plus 3,000 kVAR of lagging reactive load. The transformer is the whole point, and the arithmetic shows why. At 24 kV a 5,000 kVA connection draws about 120 A, against roughly 7,518 A for the low-voltage 8400 at 6,250 kVA and 480 V. That turns a seven-and-a-half-thousand-amp parallel bus problem into a single modest medium-voltage cable set. This also explains the capacity inversion against the lower-numbered 8400. The oil-filled transformer, its enclosed four-fan cooling compartment and the oil containment bund consume a large share of the container, so the extra 10 ft does not fully offset what they take and the 8850 lands 1,250 kVA below the 8400 while carrying roughly 7,000 kg more mass. The model number tracks voltage class, not kVA. The procurement gap on this model is the transformer itself. Its kVA rating, impedance, vector group, BIL and oil volume are all absent from Avtron's documentation, which defers to the transformer maker's own manual.

Why it matters

A medium-voltage test that would otherwise need a hired transformer, a temporary low-voltage bus and thousands of amps of cable arrives as one container and a 120 A connection at 24 kV. That is the difference between a practical campus acceptance test and one that gets deferred. The trade is 1,250 kVA less capacity than the low-voltage 8400, a 30 ft box, roughly 7,000 kg more mass and an oil regime the 8400 does not carry.

Who buys it

Owners and commissioning agents with a medium-voltage connection point and no practical low-voltage tie. As campus loads climb, the point where capacity must be proven moves upstream to 13.8 kV or 24 kV distribution, and a 480 V load bank cannot reach it without borrowing a transformer. Avtron names the 8850 for medium-voltage commissioning and maintenance in its March 2026 international data centre brochure.

Role in the data center

Medium voltage commissioning and maintenance, the slot Avtron gives it in the March 2026 international data centre brochure. It applies block load upstream of the low-voltage distribution, at 0.8 pf, for campus distribution ring and substation acceptance work and for proving medium voltage switchgear. Because the connection is at medium voltage, periodic capacity testing on a live campus does not require a tie into occupied halls. Note the regional split: the Americas edition of the same brochure fills this slot with the resistive 9100 instead.

Key specifications

Technical summary

Capacity: up to 5,000 kVA at 0.8 pf, not kW. Components at 5,000 kVA: 4,000 kW real plus 3,000 kVAR lagging (computed from 0.8 pf). Load step resolution: 1 kW and 5 kVAR. Voltage: 690 to 24,000 V on the data sheet; 3.3 kV to 24 kV in the 2026 brochure. Line current at 5,000 kVA: about 120 A at 24 kV and 875 A at 3.3 kV (computed). Frequency: 50, 60 and 50/60 Hz builds. Container: 30 ft ISO style, 9125 x 2440 x 2590 mm, CSC certified for top loading. Weight: approximately 23,500 kg per the 8800 Series manual, absent from the 8850 sheet. Transformer: oil filled, hermetically sealed, forced-air cooled, over-temperature trip, oil bund. Cooling: 2 fans for the resistive elements and 4 for the transformer, up to 35 m3/s. Clearance and noise: at least 1 m on the intake side; 88 dBA at 50 Hz at 3 m. Control, ambient, warranty: SIGMA 2; 35 deg C at up to 90 percent RH; 24 months.

Major variations

Voltage is the ordering variable and it is set by the transformer, so it is not a field adjustment. The data sheet publishes 690 to 24,000 V while the 2026 data centre brochure quotes 3.3 kV to 24 kV, and no capacity-versus-voltage table is published for the range between. Frequency builds are 50 Hz, 60 Hz and 50/60 Hz. Series siblings cover the adjacent cases: the 8800 is the same voltage class at 1,000 kVA and up in a 20 ft container, and the 8750 is resistive only to 33 kV in the same 30 ft box. The capacity inversion against the 8400 is deliberate rather than an error. The 8400 is the low-voltage machine at 380 to 690 V and reaches 6,250 kVA at 0.8 pf in 20 ft, while the 8850's oil-filled step-down transformer, four-fan cooling compartment and oil bund consume the extra 10 ft and cap it 1,250 kVA lower. Model number tracks voltage class, not kVA.

Configurations and options

SIGMA 2 control, with the wider SIGMA platform available for networking, Modbus and SIGMA Unity software. The container carries its own medium voltage ring main unit, which the user manual commissions as a separate step under a third-party manual. The transformer is oil filled and hermetically sealed with forced-air cooling, over-temperature warning and trip levels and an oil containment bund. Cable entry is a single side gland plate access point of 216 x 300 mm.

Compatibility and dependencies

Voltage compatibility is fixed by the installed transformer, so confirm the actual primary rating rather than assuming the published 690 to 24,000 V span covers your site. Cooling is air only, up to 35 m3/s, with at least 1 m of clear space on the air intake side and clear space above the outlet, so no external coolant loop is required. Transport is the constraint that most often decides whether this unit can reach a site. Avtron's own wording is 30 ft ISO style container at 9,125 mm, and standard ISO chassis are 20 ft, 40 ft and 45 ft, so it moves on a low-bed or extendable chassis rather than the flatbed pool that handles 20 ft boxes. At approximately 23,500 kg it is inside normal crane capacity but is a real axle-loading question on temporary site roads. The third dependency is oil: the step-down transformer is oil filled and sits over a containment bund, so the site carries spill and permitting duties a dry unit does not.

Pricing and availability

Comparable secondary-market band: 49.78–70.54 $ per kW of real component. Trend: stable The medium voltage tier has no published price at any condition from any seller, so there is no five-year price series for this model. Residual value here is dominated by the transformer and ring main unit rather than by load bank content, so the category's usual observation that resistive elements outlive their controls does not carry the valuation argument on this model. Lead time, new: No 8000 Series unit appears on Avtron's stock list. The 8850 contains a transformer configured to the customer's voltage and a ring main unit, both bought-in items with their own supply chains, so lead time is quote-only. The 3 to 4 week quick-ship Avtron publishes on four 4800 Series builds applies to that series, not to the 8850.. Lead time, used or refurbished: No used 8850 is publicly listed by any reseller, so no used lead time applies.. Warranty, new: 24 months as detailed in Avtron's Conditions of Trade, per the pub 5123 rev A data sheet. The transformer and ring main unit carry their own separate terms.. Warranty, used: Avtron's 24 month term runs from its Conditions of Trade and does not transfer on resale. The step-down transformer and the ring main unit carry their own makers' terms rather than Avtron's, so a used purchase should establish all three separately..

Lifecycle and maintenance

No MTBF or design life is published. The data sheet publishes a 24 month warranty per Avtron's Conditions of Trade. The 8800 Series user manual publishes Daily, Monthly and Annually maintenance intervals and a commissioning sequence of visual inspection, control circuit and fan verification, transformer commissioning and ring main unit commissioning, the last two under external manuals. The category's usual lifecycle argument is weaker here and buyers should know it. Resistive elements outlive their controls, which is why used resistive banks hold value, but this model's economics are dominated by an oil-filled transformer and a medium voltage ring main unit that age on their own schedules and are not load bank components at all. Only 4,000 kW of the 5,000 kVA draws fuel, so a four-hour run takes 16,000 kWh, and the transformer oil sits over a bund with spill duties a dry unit has not.

Thermal and emissions profile

No on-site combustion and no direct emissions. At up to 5,000 kVA and 0.8 power factor the resistive section rejects roughly 4,000 kW as heat through the container discharge; the integral oil-filled step-down transformer adds its own no-load and load losses as heat and introduces an oil-containment consideration at the pad, which is an environmental item to plan for even though it is not an emission.

Common failure points

• Step-down transformer — Over-temperature warning or trip, oil seepage, or rising top-oil temperature at unchanged load
• Transformer cooling fan group — Transformer over-temperature under load while the resistive elements run cool
• Medium voltage ring main unit — Failure to close, interlock faults, or partial discharge indications at the medium voltage terminations
• Resistive elements and contactors — A 1 kW or 5 kVAR step fails to pick up, or phase imbalance appears at a fixed step
• Reactor and inductive section — Achieved power factor drifts off target while the kW component reads correct
• Oil containment bund — Standing liquid in the bund, or a bund drain left open
• Container structure and corner castings — Corrosion or deformation at corner castings, roof rails or door frames

Inspection checklist

Rating unit on the nameplate: confirm kVA at 0.8 pf, since 5,000 kVA is 4,000 kW plus 3,000 kVAR and this model is routinely miscatalogued as 5,000 kW. Voltage class on the nameplate: the data sheet range is 690 to 24,000 V and the brochure quotes 3.3 to 24 kV, so read the actual transformer primary rather than assuming your site voltage is covered. Transformer condition: it is oil filled and hermetically sealed, so check for seepage at the tank, bushings and radiators, and obtain oil test results before purchase. Transformer documentation: oil volume and type are not in Avtron's manual, which defers to the transformer maker's own manual, so require that manual as a condition of sale. Oil bund integrity: the containment bund is a published feature, so verify it is intact, drained and not carrying stored oil or water.

Procurement channels

New through Avtron and its distributors, quote-only across the whole medium voltage tier. Curtis Power Solutions lists the family as the ASCO Froment 8000 Series containerised range, with no prices. SteadyPower publishes prices for 24 Avtron resistive builds and none for any medium voltage or containerised unit. There is effectively no used channel. No used medium voltage load bank is publicly listed at any rating, and no used load bank above 750 kW is publicly listed at all. No published rental fleet lists a medium voltage containerised unit, and Avtron states it does not rent its own equipment.

Regional notes

Built primarily for international practice: 50, 60 and 50/60 Hz, 690 to 24,000 V, and named only in the international edition of the March 2026 data centre brochure. The Americas edition offers the resistive 9100 at 4,160 V to 13.8 kV in this slot instead. The general arrangement drawing is copyright NJ Froment & Co Ltd, Avtron's UK operation, which is where the container line is engineered.