OXA260U3O3QT ABB TruONE 400 A IEC 4-Pole Automatic Transfer Switch Level 3 Overlapping Neutral

Why Choose the ABB OXA260U3O3QT TruONE Automatic Transfer Switch?

The ABB OXA260U3O3QT is a 400 A IEC, 4-pole TruONE automatic transfer switch (ATS) designed for automatic transfer of electrical loads between two power sources. Part of the ABB TruONE ATS range, it combines the switching mechanism and automatic transfer controller within an integrated open-style assembly for critical, standby and industrial power distribution systems.

This model features Level 3 controls, open-transition I-II operation and an overlapping neutral. The overlapping neutral arrangement maintains the neutral connection to the load during transfer between sources, with a neutral contact overlap period below 100 ms and the overlapping neutral pole located on the right-hand side.

The OXA260U3O3QT has a 400 A IEC rating and 260 A UL rating with a 4-pole configuration. It uses a top-entry arrangement with Source 1 and Source 2 connections at the top and load connections at the bottom, while phase barriers on the load side are included for this 400 A-class configuration.

Key Advantages

• 400 A IEC rated automatic transfer switch for critical and standby power systems.
• 260 A UL rated current for UL-based installations.
• 4-pole configuration with overlapping neutral functionality.
• Integrated Level 3 controls for automatic source transfer, monitoring and configuration.
• Open-transition I-II operation without a stable OFF position between sources.
• Overlapping neutral maintains neutral continuity during source transfer.
• Top source connections and bottom load connections support the specified switchboard arrangement.

Key Features

• ABB TruONE ATS series.
• 400 A IEC rated current.
• 260 A UL rated current.
• 4-pole automatic transfer switch.
• Level 3 controller.
• Open-transition I-II operation.
• Overlapping neutral with contact overlap below 100 ms.
• Overlapping neutral pole positioned on the right-hand side.
• Source 1 and Source 2 connections at the top.
• Load connections at the bottom.
• Manual operating handle included.
• Supplied with a 2 m connection cable between the detachable HMI and ATS frame.
• Load-side phase barriers included for the 400 A-class configuration.

Integrated Automatic Transfer with Overlapping Neutral

The ABB TruONE platform integrates the transfer switching mechanism and automatic control functions into a purpose-built ATS assembly. This approach reduces the number of separate components and connections required in a conventional automatic transfer system while providing coordinated source monitoring and transfer operation.

The OXA260U3O3QT combines open-transition I-II switching with an overlapping neutral arrangement. During transfer, the neutral remains connected to the load and the neutral contacts overlap for less than 100 ms. Its 400 A IEC rating, Level 3 controls and top-source/bottom-load connection layout make it suitable for demanding commercial, infrastructure and industrial power distribution systems.

Typical Applications

• Automatic mains-to-generator transfer systems.
• Critical and standby power distribution systems.
• Commercial and industrial electrical switchboards.
• Emergency and alternative power supply installations.
• Building services and infrastructure power distribution.
• Industrial systems requiring automatic source transfer with overlapping neutral.