Victron Energy Autotransformer, 120/240V AC, 50A, 50/60Hz, IP21

Overview

The Victron Energy ITR000100052 is a 120/240 VAC 50A autotransformer for step-up, step-down, and split-phase load balancing in marine AC power systems. It works with 120/240V AC systems at 50/60 Hz, making it a practical component for boats using split-phase shore power, generators, or Victron inverter/charger installations where load balance between legs matters.

In a split-phase setup, this unit can create a usable neutral point and help balance uneven 120V loads across a 240V supply. That can be useful on cruising boats and larger onboard electrical systems where one leg may carry heavier cabin, galley, HVAC, or utility loads than the other.

The unit uses a toroidal transformer in an aluminium enclosure with IP21 protection, so it belongs in a protected electrical space rather than an exposed deck or washdown area. Its rated 240V feed-through current is 50A, with neutral current rated at 45A continuous at 40°C and 55A for 30 minutes.

Key features

• Supports 120/240 VAC step-up, step-down, and split-phase output balancing in AC power systems.
• Rated for 50A maximum 240V feed-through current, with a 50A two-pole input circuit breaker.
• Works on 50/60 Hz AC systems commonly used with shore power, onboard generators, and inverter/charger installations.
• Toroidal transformer construction helps keep the unit suitable for demanding onboard electrical installations.
• Aluminium enclosure with IP21 protection for installation inside a dry, protected compartment.
• Ground relay is included for use with Victron Multi or Quattro inverter/chargers when the installation requires it.
• Measures 460 x 214 x 110 mm and weighs 11.5 kg, so mounting location and support should be planned before installation.

Installation and setup

This autotransformer is part of the vessel’s AC distribution system and should be installed where it can be wired, protected, and serviced correctly. Because it handles 120/240 VAC power and neutral bonding behavior can affect safety devices such as GFCI protection, installation should be handled by a qualified marine electrician familiar with ABYC-style AC system practices and Victron inverter/charger layouts.

The IP21 enclosure is intended for a sheltered location. A dry electrical locker, technical space, or protected power equipment area is a better fit than an engine-room location exposed to spray, dripping water, or heavy salt air.

Compatibility and fit

This model suits boats with 120/240 VAC split-phase architecture where load balancing or voltage conversion is required. It can be used with shore power, generator output, or inverter/charger systems when the overall system design calls for an autotransformer rather than separate stacked inverter operation.

Owners upgrading a marine AC system should confirm the vessel’s service size, breaker arrangement, neutral and grounding plan, inverter/charger model, and available mounting space before purchasing. The 50A rating is the key fit point for this version.

Use cases on board

On larger cruising boats, sportfishing boats, and liveaboard systems, uneven 120V loads can make one leg of a split-phase supply work harder than the other. This autotransformer helps manage that kind of imbalance in systems where 240V supply is available but onboard loads are spread across two 120V legs.

It is also a useful component when a vessel’s AC design needs 120V from 240V, 240V from 120V, or a balanced split-phase arrangement tied into a compatible Victron power system.

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