AC Changeover Switch

Changeover units for shore power, generator and inverter

If an onboard system has several 230 V sources such as shore power, generator and inverter, it needs a changeover unit. It prevents two sources from feeding in at the same time and separates them on all poles – to protect people, loads and the installation. The range includes the automatic changeover units of the philippi LAU series, the automatic bow-stern changeover LAE 241, and manual changeover and cam switches.

In brief: Automatic changeover units select the available source themselves and only connect a generator once it has stably reached its rated voltage. Manual cam switches are simpler; the source is selected by hand.

The range

• LAU 216 / LAU 216 F – automatic changeover shore/generator or inverter
• LAU 325 / LAU 325 F and LAU 340 / LAU 340 F – automatic changeover between three sources (shore, generator, inverter)
• LAE 241 – automatic bow-stern changeover between two shore connections
• CAG 20 BH / CAG 20 LG – bow-stern or shore-generator changeover switch
• Cam switches and main switches CH 16A and CA 63A – manual for shore/inverter or shore/generator/inverter, with blank plate

The F versions also contain an RCBO circuit breaker. Data and generator ratings of the LAU series are compared under AC shore power units.

Control via the P-BUS system

The LAU series is prepared for the P-BUS system. With the PSM or PSL system monitors, changeover delay, voltage limits and source priority can be set and the active source displayed. An additional output circuit can switch off loads such as the charger or water heater in inverter mode to spare the battery.

How shore connection, changeover and galvanic isolation work together is explained on the topic page Shore power on boats.

Frequently asked questions about changeover units

When do I need a changeover unit?

As soon as there is more than one 230 V source on board, for example shore power and generator or shore power and inverter. The changeover unit prevents two sources from feeding the onboard system at the same time, which can damage generator, inverter and loads and create dangerous conditions. The sources must be separated from each other on all poles.

Automatic or manual changeover?

The automatic changeover units of the LAU series select the available source themselves and only connect a generator once it has stably reached its rated voltage. Manual cam switches such as CH 16A or CA 63A are simpler and cheaper, but require the source to be selected by hand. Both separate the sources safely.

What does the F in LAU 216 F, 325 F and 340 F mean?

The F versions LAU 216 F, LAU 325 F and LAU 340 F already have an RCBO circuit breaker built in. In addition to changeover, they therefore also provide the residual current and cable protection at the shore connection required by ISO 13297. With the versions without F, this protection must be provided separately.