Victron 3600W isolation transformers are no longer available. The part numbers ITR040362041 (manual 115/230V) and ITR050362041 (Auto) appear as manufacturer discontinued across authorized distributors. Boat owners and marine electricians usually search by amperage first. A 25A shore circuit is the practical size this transformer served. The kVA rating still matters because it confirms the transformer can carry that continuous load without overheating. The MarinePuck MP3.6 is the direct electrical drop-in for both the 3600W rating and the 25A service class.
Why the Victron 3600W Matters
A 25A shore inlet is common on mid-size coastal cruisers, sailboats, and smaller motor yachts. At 120V that is roughly 3000W of continuous capacity before derating. At 230V it is about 5750W. The Victron 3600W unit sat in the middle of that range and was widely specified for 25A-class services. The Auto version added automatic sensing between 115V and 230V shore supplies, which was useful for boats that moved between regions.
When Victron moved the line to larger 4500W and 8000W successors, the exact 3600W form factor disappeared. A larger transformer does not always fit the same locker or bulkhead space. It also changes the continuous current the upstream breaker and wiring must support. For boats that were designed or retrofitted around a 25A isolation transformer, a same-size replacement is usually the cleaner path.
| Search term boat owners use | What it actually means | Why both matter |
|---|---|---|
| 25A isolation transformer | Shore breaker / inlet rating | Determines wire size, breaker, and inlet hardware |
| 3600W or 3.6 kVA | Continuous transformer rating | Confirms the unit can carry the 25A load without thermal issues |
| ITR040362041 | Specific Victron part number | Exact match for manuals, parts lists, and existing installs |
| ITR050362041 | Auto-sensing version of the same rating | Same electrical job with automatic voltage selection |
What Discontinued Actually Means
Authorized distributors list the 3600W models as NLA or manufacturer discontinued. Some show the 4500W unit (ITR040452042) as the factory successor. That larger unit is electrically capable, but it is not a form-fit replacement. Weight, dimensions, and mounting holes change. For a retrofit where the original Victron 3600W is being removed from a tight space, the larger unit often requires cabinet modifications or a new location.
The original Victron 3600W used a toroidal core inside a metal enclosure. It included soft-start circuitry to limit inrush and reduce nuisance trips on the shore breaker. Output voltage was raised by a 1:1.05 ratio. The metal case required grounding considerations and added weight (approximately 50–53 lb). Dimensions were roughly 14.25 × 10.15 × 8.6 inches. These details matter when the replacement has to land in the same physical envelope.
MarinePuck MP3.6 as the 25A / 3600W Drop-In
The MarinePuck MP3.6 is a 3.6 kVA toroidal isolation transformer built for the same continuous load class. It is hermetically sealed in a non-metallic flame-rated ABS enclosure and epoxy potted. There is no metal case to ground and no corrosion path through the housing. Dimensions are 10 inches outer diameter by 5 inches high, and weight is approximately 45–50 lb. The smaller package is the practical advantage when the original Victron unit is being pulled from a locker or bulkhead.
| Spec | Victron 3600W (ITR040362041 / ITR050362041) | MarinePuck MP3.6 |
|---|---|---|
| Continuous rating | 3600 W / 3.6 kVA | 3.6 kVA |
| Typical service class | 25A (30A shore with margin) | 25A / 30A class |
| Core type | Toroidal | Toroidal |
| Enclosure | Metal | Non-metallic ABS, epoxy potted |
| Approximate weight | 50–53 lb | 45–50 lb |
| Approximate size | 14.25 × 10.15 × 8.6 in | 10 in OD × 5 in H |
| Soft-start | Included | Available in the MarinePuck line |
| Boost capability | Limited | 104 V / 208 V taps standard |
| Neutral bonding | Secondary neutral available | Secondary neutral available for single boat-side bond |
| Origin | — | Shelton, Connecticut |
| Certifications | — | UL Listed Marine E509703, ignition protected |
Both the amperage and the kVA rating line up. A 25A continuous load at 120V is 3000W. The 3.6 kVA transformer provides headroom for the continuous rating plus the soft-start and thermal margin needed for marine service. The non-metallic construction removes the need to treat the case as a grounded metallic enclosure under ABYC E-11 when an ELCI is installed on the input.
How the Electrical Function Stays the Same
Galvanic isolation is the core job. Shore power enters the primary. The secondary is electrically separate. The shore green is capped. The secondary neutral is bonded once on the boat side. This breaks the conductive path that drives galvanic corrosion while still allowing a proper grounded system on the vessel.
The MarinePuck MP3.6 uses the same toroidal principle. Lower interwinding capacitance and reduced stray field compared with traditional laminated designs help keep leakage low. The epoxy potting and non-metallic housing keep moisture out and eliminate a metal path that could otherwise require additional bonding or create a corrosion site. Soft-start is available in the MarinePuck line to manage inrush the same way the original Victron soft-start circuit did.
For boats that move between 120V and 230V regions, the dual secondary windings on the MarinePuck can be configured for the required output. The Auto version of the Victron unit handled sensing internally. The MarinePuck handles it by winding configuration and the existing shore inlet and breaker arrangement. In both cases the continuous rating stays at 3.6 kVA.
Retrofit Path for an Existing ITR040362041
Most replacements follow the same sequence:
- Isolate the shore circuit and verify zero voltage.
- Photograph the existing primary and secondary landings.
- Remove the Victron 3600W unit. Note any soft-start wiring or voltage-select jumpers.
- Mount the MarinePuck MP3.6 with the central carriage bolt. Leads can exit rearward through the mounting surface or radially.
- Land the shore inlet on the primary. Cap the shore green.
- Bond the secondary neutral once on the boat side.
- Confirm an ELCI breaker is installed ahead of the primary.
- Re-energize and verify voltage and polarity at the panel.
The smaller diameter and lower height often allow the MarinePuck to land in the same footprint or in a tighter adjacent space. Custom lead lengths are available if the original run was short or if the new unit sits slightly offset.
Why Size and Weight Matter on a 25A Boat
A 25A isolation transformer is frequently installed in an engine-room locker, under a settee, or on a bulkhead with limited clearance. The original Victron metal enclosure occupied a rectangular volume. The MarinePuck’s round, low-profile shape and roughly 5-inch height change the clearance calculation. In practice this has allowed installations where the original unit was a tight fit or where the larger 4500W Victron successor would not land without cabinet work.
Weight reduction of a few pounds is secondary to the mounting simplicity. A single central bolt replaces a multi-hole metal flange in many cases. The non-metallic housing also removes the need to bond the case itself, which simplifies the grounding conductor run.
FAQ
Is the Victron 3600W still available?
Authorized distributors list ITR040362041 and ITR050362041 as manufacturer discontinued. Remaining stock is limited and not a reliable long-term source.
Does a 25A boat need a 3600W transformer?
Yes. A 25A continuous load at 120V is 3000W. The 3.6 kVA rating provides the continuous capacity and thermal margin expected for marine isolation service.
Is the MarinePuck MP3.6 a form-fit replacement?
It is an electrical drop-in at the same 3.6 kVA / 25A-class rating. Physical dimensions are smaller, which is usually an advantage in retrofit spaces.
Does it include soft-start?
Soft-start is available in the MarinePuck line and addresses the same inrush concern the original Victron circuit handled.
What about the Auto version?
ITR050362041 is also discontinued. The MarinePuck MP3.6 covers the same electrical function. Voltage configuration is handled by the secondary windings rather than an internal auto-switch.
Is an ELCI still required?
Yes. ABYC E-11 places the ELCI on the input side of the isolation transformer. The MarinePuck does not change that requirement.
Where is the MarinePuck made?
Shelton, Connecticut.
Product Callout
Bridgeport Magnetics MarinePuck MP3.6
3.6 kVA / 25A-class toroidal marine isolation transformer. Electrical drop-in for the discontinued Victron 3600W (ITR040362041 and ITR050362041). Non-metallic, UL Listed Marine, ignition protected. Made in the USA.
Phone: (203) 954-0050
Email: [email protected]
bridgeportmagnetics.com/marinepuck/
