What is Digital Switching?
Digital Switching is the control of electrical circuits by a computer logic unit. In other words, it is like replacing the circuit breakers, fuses and switches on a boat's electrical panel with intelligent, configurable boxes.
A basic digital switching system allows to turn on or off a device. No more or less than a simple switch, but on a screen. More complex systems also allow to monitor information (battery voltage, reserve level). Finally, the most efficient systems allow you to create scenarios. For example, it is possible to authorize the operation of the windlass only if the boat's speed is less than 1 knot. With this type of system, such as Garmin's EmpireBus, the only limit is the boater's imagination (and wallet)!
Control units placed as close as possible to the consumer
A digital switching installation changes the electrical wiring of the boat. Of course, it is possible to replace the electrical panel by the connection boxes. But it is not very smart to gather all the wires coming from the consumers in one point on board. The interest of the system consists in placing the boxes at strategic places to limit the distance with the consumers. This way, fewer cables will be passed and especially smaller sections. Indeed, the longer an electrical path is, the larger the diameter of the cable is needed to maintain the intensity.
On a catamaran, for example, one box will be placed in each hull and one on the nacelle. In a motorboat, one can be placed in the engine room to retrieve mechanical data and another in the cockpit at the center of the boat. Each unit is connected to the others on the NMEA 2000 network, which transmits the information to the onboard displays.
as an example, a Digital Switching installation on an 11m sailing boat (Biloup 36) saw the original 100m wiring reduced to 30m!
Computer intelligence for management
The rest is programming. One can imagine different scenarios: Do not start the engine if the bath scale is not raised. If the battery voltage is too low, start the generator. If the wind strengthens and exceeds 25 knots, display a message advising to reef a sailboat. Block the engine start if the shore power is on This kind of scenario can be designed for comfort as well as for safety. For example, you can determine that the bulb of the anchor light at the masthead is burnt out if the power consumption is at 0 when you switch on. The system will tell you directly that you are in default.
Always stay on top of things
The first complaint about this type of installation is that it is impossible to intervene in case of a problem. If the screen of the plotter which controls the system stops, what to do? It is enough to take again the hand directly on the box. This one displays leds to give the state of its connections. With a simple button, you can turn on or off the position. You just need to have a correspondence table which indicates that the n°4 corresponds to the lighting of the square.
More expensive than a conventional electrical panel
A Digital Switching installation is more expensive than a simple electrical panel, but it offers a lot of additional services. For a shipyard producing new boats, the gain is real since it simplifies the wiring harness, reduces the size and footprint of the electrical panel, decreases the length of cable (saving price and weight) and also decreases the wiring time (saving labor).
Some manufacturers also offer waterproof modules (this is the case of EmpireBus) which make them very suitable for small boats such as semi-rigid or open. We know that on these units, the inside of the consoles are often exposed to humidity and the space to install an electrical panel is often limited.
For new boats or used units
You can see that the EmpireBus system is suitable for a new boat as well as for a renovation. This is the case of my Amerglass dating from 1973 on which I undertook to change the entire electrical network. I took the opportunity to equip myself with EmpirBus boxes. A practical test to validate the concept
