Marine Isolation Transformers

Stainless Steel or Light Gray Powder Coated Enclosures

Marine Isolation transformers are used on-board vessels or dock-side as part of marina power distribution systems. The isolation transformers totally isolate the earth-bonded shore AC power from on-board electrical systems and greatly reduce the risk of shock caused by defective
electrical systems, and largely eliminate corrosion of metal parts caused by stray AC current.

Problems with the AC supply may be caused by insulation breakdown, immersed wiring, incorrect wiring or equipment failure. If the 3rd (green) ground wire is connected to the on-board bonding circuit, corrosion, excessive erosion of zinc electrodes and shock due to stray current may result. In addition corroded wiring in the shore installation may send considerable voltages down the ground wire without tripping the AC circuit breaker causing damage to on-board electronics.

Our five standard design marine isolation transformers are available in either light gray powder coated or stainless steel enclosures.

 Light Gray Powder Coated Enclosure  A 12 kVA Marine Isolation Transformer was installed on-board this ocean going Nordhavn
46 "Starlet" owned by Mark Ullmann

Product Specifications

Advantages of Toroidal Isolation Transformers

The advantage of a toroidal transformer is that it allows the stainless steel enclosure to be much smaller than when a conventional stacked lamination type transformer is used. Smaller dimensions also mean much lower total weight of the enclosed isolation transformer.
Both features are of paramount importance on-board vessels of any size.

Isolation Transformer Safety Standard Certifications

UL 60601.1, CSA C22.2 No 601.1-M90 (1990), EN61558-1, IEC60601-1, CE Marking
Medical Safety Standard with maximum leakage current of 100 to 300 microamperes depending on the power rating of the transformer.

Enclosure Specifications

NEMA 4X  style, 14 gauge light gray powder coated or stainless steel water tight enclosure with hinged and lockable door. Input and output wires are terminated through sealed stress relief cable glands at the bottom of enclosures to a terminal block inside the enclosure.

The 3.6kVa Marine Isolation Transformer"Marine Iso-Puck"



  • Powder-Coated Steel Housing
  • Completely Epoxy-Potted (Sealed) Transformer
  • Embedded Thermistor To Manage In-Rush Current
  • Light-Weight (40lbs), Installs Easily with 2 Studs Thru Bulkhead (plus a wiring hole)
  • Water-Proof Enclosure For Termination
  • Competitively Priced
  • Unsurpassed Simplicity
  • Complies with UL 60601.1 Safety Certifications
  • Made in the USA

Marine IS0-Puck Download





Downloadable PDF of 3.6kVa Marine ISO-PUCK