Hubbell Isolation Transformers

Hubbell Marine Isolation Transformers: Shore Power Safety Done Right

When it comes to protecting a vessel's electrical systems at the dock, few names carry as much authority as Hubbell Marine. Long regarded as the shore power experts in the marine industry, Hubbell has engineered a purpose-built line of isolation transformers that addresses two of the most serious hazards boaters face when plugging into shore power: galvanic corrosion and electric shock drowning (ESD).

What Makes Hubbell Isolation Transformers Stand Out

Isolation transformers from Hubbell Marine protect a vessel's delicate electronic equipment from damaging surges and spikes, while simultaneously eliminating the possibility of electric shock drowning caused by stray current leaking into the water from a faulty shore connection. Especially important on metal-hulled vessels but offering significant benefits for all boats, Hubbell isolation transformers protect metal fittings from potentially dangerous galvanic corrosion by isolating the onboard AC system from the connected shore power AC system, while still maintaining the safety provided by the shore power AC green grounding wire.

Model Range and Configurations

UL certified and ABYC compliant, Hubbell isolation transformers are engineered for 50A and 100A systems, available in 50/60 or 60 Hz and in 15 or 25 kVA configurations to suit US and EU markets — and each unit comes pre-wired for 120/240V applications in a compact, lightweight design that utilizes little onboard space.

Boaters can choose between a white powder-coated or 316 stainless steel housing to complement their onboard equipment. The 316 stainless option is particularly well suited to saltwater environments where corrosion resistance is paramount.

The ISO-Boost Advantage

One of Hubbell's most notable differentiators in this category is its optional auto-boost technology. Hubbell isolation transformers measure shore power on startup, and if the reading falls significantly, the device instantly boosts output by up to 12.5% to ensure a constant flow. An optional auto-boost module is available for all models — this feature engages automatically if the voltage at the dock falls between 195–220V, ensuring consistent power — and an LED indicator display mounted outside the housing provides easy access to transformer status.

Built for the Marine Environment

Hubbell's construction philosophy prioritizes resilience in harsh marine conditions. These units are UL listed, CSA certified with UL-3R enclosures that meet or exceed all listing criteria including NEMA, ANSI and OSHA standards. They feature two full current-carrying shields, a vibration-resistant design, and exceed ABYC's 4000 Volt HIPOT test requirement. An encapsulated, completely enclosed design using electrical grade silica and resin compounds seals the core and coil against all moisture and air.

Hubbell isolation transformers offer easy access to the main module and other internal components, and high-quality terminal blocks ensure reliable wire management. Integral mounting brackets make secure installation possible even in tight quarters.

These versatile systems can be wired for either a polarization or isolation transformer system , giving marine electricians the flexibility to match the installation to the vessel's specific requirements and compliance needs.

Why Choose Hubbell for Isolation Transformers

With decades of expertise in marine electrical products, Hubbell brings industrial-grade engineering to the marine market. Their isolation transformers are not afterthoughts — they are purpose-designed for the rigors of dock life, built to handle voltage fluctuations at unfamiliar marinas, and certified to the standards that professional marine electricians and ABYC-compliant boatyards demand. Whether you are outfitting a cruising sailboat or a large powerboat, Hubbell's isolation transformer lineup delivers the peace of mind that comes from knowing your onboard systems — and your crew — are protected.