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Mastervolt

55003500

Masterswitch box 25 kW (230 V)

The Mastervolt Masterswitch 25 kW 230 V is a high-capacity automatic AC transfer switch designed to handle up to 125 A between two power sources (generator, shore power, or inverter). Certified to IP55 and featuring adjustable delay on connection, it effectively protects your onboard electrical network without requiring a MasterBus connection.

Includes: Masterswitch 25 kW unit (external fuses and circuit breakers not supplied).

Retail priceBenefit from the professional rate

1.191,16€

1.191,16€ ~~1.383,48€~~

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In stock

Free pickup point shipping over €150 in France
Pickup at Skysat possible

Custom installation

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Request a quote

Installers near you

thanks to our network of approved installers

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Support service

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Technical specifications

Nominal voltage	230
Amperage	125.0
Nombre de circuits	2.0
Nombre de pôles	Single-phase
Parcs de batteries supportés	0.0
Méthode de protection des circuits	Fuses
Courant continu nominal du DVSR	0.0
Mounting type	Mural
IP rating	IP55
Display type	None
Certifications	CE
Taille maximale de cosse de câble	50
Operating temperature range	-5 to 60
Dimensions (W x H x D)	241 x 291 x 168
Weight	3.8
Section de câble AC recommandée	4-50
Surveillance de la fréquence AC	No
Nombre d'entrées AC	2
Nombre de sorties AC	1
Type de réseau AC	Single-phase
Plage de température ambiante	-25 to 70
Type de connexion du câble	Terminal block
CE marking	Yes
External fuses required	Yes
Fusible intégré	No
Galvanic isolation	No
Délai d'entrée groupe	0-10
Temps de stabilisation par défaut (Générateur)	10
Grounding required	Yes
Type de source (Entrée 1)	Generator or Shore Power
Type de source (Entrée 2)	Converter or Dock
Input voltage range	200-250
Manuel d'installation inclus	Yes
Indication LED sur boîtier	No
Fréquence nominale	50/60
Marine-ready	Yes
Compatible MasterBus	No
Approuvé pour usage médical	No
Nominal current	125
Nominal puissance w	25000
Nombre de phases	1
Max power consumption	26
Standby consumption	0
Depth (mm)	168
Height (mm)	291
Product type	Automatic AC transfer switch
Width (mm)	241
Dispositif différentiel (RCD) requis	Yes
Relative humidity	95
Remote control compatibility	No
Storage temperature range	-60 to 80
Priorité de commutation	Priority input 1
Type de commutateur de transfert	Automatic

Detailed description

The Mastervolt Masterswitch 25 kW 230 V box is the decision-making core of your AC electrical system on board. Designed to replace manual switching between two AC power sources, this automatic transfer switch handles up to 25 kW with a maximum current of 125 A at both input and output. Unlike basic switches, this industrial model ensures seamless transition between a generator, shore power, or inverter, with ultra-fast switching times (12 to 22 ms on startup, 4 to 19 ms on shutdown).

Intelligent priority management and system protection

The Masterswitch 25 kW features two AC inputs and a single output. Input 1 has absolute priority, ideal for connecting a generator or shore power. To preserve the generator’s mechanics and protect the onboard network from voltage and frequency variations, an adjustable delay of 0 to 10 seconds (default set to 10 seconds) allows the generator to stabilize before taking the load. Input 2, with secondary priority, automatically takes over if no voltage is present on the primary input, consuming no power (0 W) when used alone with an inverter. At maximum load across all inputs, the unit’s internal consumption remains minimal at 26 W.

Robust design for marine environments

Rated IP55 for water resistance, this 3.8 kg box (dimensions 291 x 241 x 168 mm) is built to withstand humid conditions and extreme temperatures (from -5 °C to 60 °C in operation). Installation is simplified with terminals accepting large-section cables, ranging from 4 to 50 mm² (AWG 10 to 1/0). While it is not compatible with MasterBus nor equipped with integrated circuit breakers (unlike the Masterswitch Fuses version), its pure electromechanical design makes it an absolutely reliable solution for vessels requiring heavy-duty and secure energy management.

Documentation

Type	Nom
	EN - User and Installation Manual - Masterswitch 25 kW (230 V)
	EN - Installation and User Manual - Masterswitch 25 kW (230 V)

Expert opinion

Pol CONIN

Digital Manager

« The reference for high-power automatic switching for 230 V networks »

The Masterswitch 25 kW unit stands out as a key component for managing high power loads aboard large vessels. Its ability to handle 125 A continuously on a 230 V network makes it suitable for heavy-duty installations where reliable AC switching is critical. I particularly appreciate the adjustable mechanical delay of up to 10 seconds on the priority input: this is an essential protection mechanism to allow a generator time to stabilize its frequency before powering the vessel. While it lacks a MasterBus interface, this simplicity ensures immunity to communication failures. With its oversized terminals accepting cables up to 50 mm² and an IP55 enclosure, this is an industrial-grade piece of equipment designed to last the lifetime of the vessel, provided it is properly protected by appropriate upstream differential circuit breakers.

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Masterswitch box 25 kW (230 V)

1.191,16€

1.191,16€ ~~1.383,48€~~

Frequently Asked Questions

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What is the Masterswitch 25 kW box used for?

It automatically switches between two alternating current sources (such as a generator and a shore power inlet) to power the onboard electrical system without any manual intervention.

What is the maximum power and current supported?

This industrial transfer switch can handle high power up to 25 kW, with a maximum current of 125 A both on input and output.

How many inputs and outputs does this box have?

The Masterswitch has two AC (alternating current) inputs to connect your power sources, and a single output that redistributes power to your electrical system.

How does the priority between the two inputs work?

Input 1 has absolute priority. If a voltage is detected on it, it automatically powers the output. Input 2 takes over only when no current is present on Input 1.

Why is there a switching delay on the main input?

A switching delay (default set to 10 seconds) allows the generator to start and stabilize its voltage and frequency before taking the load, which protects your onboard electrical system.

Is it possible to modify the activation delay?

Yes, this delay is adjustable from 0 to 10 seconds. If you use input 1 to connect a shore power inlet (which does not require a warm-up time), it is recommended to set this delay to 0 seconds.

What is the switching time between the two power sources?

The transfer time is ultra-fast: count on 12 to 22 milliseconds when powering on, and 4 to 19 milliseconds when shutting down.

Do computers risk shutting down during switching?

Yes, due to the micro-break inherent in the transfer between AC sources, computers and other highly sensitive electronic equipment may lose data if not protected by a UPS.

Is the Masterswitch housing waterproof?

Yes, it meets IP55 waterproofing standards, providing effective protection against dust ingress and water jets in marine environments.

Is this switch compatible with the MasterBus network?

No, this specific model is not compatible with the MasterBus communication network.

Do we need to install external fuses or circuit breakers?

Yes, this enclosure does not include built-in circuit breakers. It is essential to install fuses and residual current circuit breakers (rated at a maximum of 125 A) on the wiring for all inputs and outputs.

What are the weight and dimensions of the device?

The device weighs 3.8 kg. Its exact dimensions are 291 x 241 x 168 mm (height x width x depth).

How should the grounding be performed?

The Masterswitch grounding terminal must be connected to the boat's or vehicle's central grounding (connected to the hull or chassis) to ensure the safety of the installation.

What are the tolerated operating temperatures?

The device is designed to withstand demanding conditions, with a specified operating temperature range from -5 °C to 60 °C.

What is the nominal voltage accepted by the switch?

It is designed for 230 V single-phase systems (with an input range of 200 to 250 V), operating at a frequency of 50 or 60 Hz.

Does the housing have LED indicators or a remote control?

No, this model is designed to be clean and industrial: it has no LED indicators on the housing nor a connection port for a remote control.

Where should I install the transfer switch on board?

Although it is rated IP55, it must be installed in a dry location, protected from direct rain, snow, excessive humidity, and condensation risks to prevent any electric shock.

Can this switch be used for medical equipment?

No, the Masterswitch is not intended for use as a component in life-support systems or medical equipment, except with a specific written agreement from the manufacturer.