Digital Switching gets easier, cheaper, and more compelling

14 Jan

Until recently digital switching has only been seen on newly built, high-end boats. Now, Maretron and CZone both have digital switching products that can be retrofitted by a boat owner or pro installer and cost under $500. But, are these products easy to install and will the boat owner benefit from the installation? Read on to find out.

Digital switching is a complex topic and there are quite a few systems from several different manufacturers available today with more coming. This entry won’t be able to cover all the capabilities of the systems covered nor the specifics of installing each one. Over the coming year I plan to cover several of these systems in greater depth and show what’s involved in installing and configuring these systems to integrate them into your boat.

Benefits of digital switching

What’s a digital switch and why should I care? That’s a reasonable question and the answer is a little involved. When compared to traditional mechanical switches, digital switching’s biggest benefits are flexibility, reduced weight, weather sealed highly reliable switches, and automation. But, digital switching can also be a little harder to understand at first and troubleshooting can involve a computer instead of a multi-meter which can be intimidating.

Reduced weight through less wiring

Have Another Day’s conventional DC panel. Each of these loads start at the batteries in the engine room then run to the panel and out to their final location

Traditional DC switching and power distribution starts with a centralized electrical panel where very large cables are run from the batteries to the panel. Then, each circuit on the boat has a wiring run from the panel to the point of use. On my own boat that means that loads like the fresh water pump, located a few feet from the house batteries, run all the way from the batteries, to the panel, and then back down to the pump. So, power for a load that is three feet from the batteries travels through about 20 feet of wire. Wire is heavy and with the number of circuits on a modern boat that can add up to many hundreds or even thousands of pounds, much of which digital switching can help reduce.

Easy control from multiple locations

Garmin 8612 controlling loads on Maretron, CZone and Yacht Devices digital switches

With traditional switching, wires must be run to each location you want a switch. On Have Another Day our salon lights can be turned on in two locations. So, there’s wire running to each switch plus another (traveller) running between the switches. This means that adding another switch can be a difficult and time consuming task that consumes lots of marine wire. With digital switching additional switches, or other controls like a touch screen or MFD, connect to the NMEA 2000 backbone of the boat; potentially dramatically simplifying installation.

Weather sealed

A traditional circuit has quite a few connections and each of these is a potential source of corrosion and trouble. Plus, mechanical switches have moving parts that are subject to failure. Digital switching circuits typically bring in a single source of power and then have a single connection to each load. There aren’t individual connections for circuit breakers, switches, and the load. Most digital switching modules are well sealed against the environment, utilize solid state switching, and offer a degree of reliability traditional mechanical switching simply can’t match.

Automation and configurability

Traditional mechanical switching can’t offer much in the way of automation, but digitally switched circuits open a world of possibilities. For example, with digital switching it’s possible to read the fresh water tank level from the NMEA 2000 network and turn off the fresh water pump if the level drops too low. Or, a circuit can be set to turn itself off after a specified delay. Plus, with more advanced digital switching systems the trip threshold can be set on a per circuit basis. So, if you have a load attached that should draw 8 amps you can set the trip threshold at 10 amps. But, if you replace that load with one that only draws 4 amps now you can easily change the trip threshold to 5 amps without making any other changes. Plus, systems with settable trip thresholds also have individual circuit current monitoring. Monitoring current consumption gives the ability to monitor and alarm if unusually high (short circuit) or low (burnt out bulb, freewheeling pump, etc) current is measured.

Cost comparison

When digital switching was first introduced to the marine market it commanded a substantial price premium over traditional mechanical switching, required certified installers, and was designed for installation as part of a new boat-build. But, as digital switching has matured, manufacturers have started offering less expensive and easier to configure versions of their products. Entry level digital switching products are available for as little as $250 for six circuits. I constructed a sample system with traditional mechanical switching for six circuits and it came to about about $200 but that doesn’t include any dimmers, which is built into most basic digital switching modules, nor does it account for a substantial difference in installation labor and supplies.

Hands on testing

I’ve been testing digital switching products from Maretron and CZone. I have Maretron’s MPower CLMD12 12 circuit digital switching module along with their VMM6 6 button keypad and from CZone I have their Contact 6 Plus 6 circuit module along and their KP2x3 6 button keypad.

Maretron MPower

Maretron’s CLMD12 is a 12 circuit digital switching unit with settable trip thresholds, current monitoring, and dimming available on each of the 12 circuits. Additionally, the CLMD12 has 7 discrete inputs. Discrete inputs allow circuits on the CMD12 to be controlled by a mechanical switch or any other control equipment that can complete a circuit. Two of the twelve circuits handle a maximum of twelve amps, six are rated at ten amps, and four are rated at five amps. But, each of these circuits can be set to trip at lower current levels if a smaller circuit needs to be protected. Final pricing for the CLMD12 hasn’t been set, but Maretron expects it to carry a suggested list price of $495, making the per circuit cost pretty affordable at just over $41.

My CLMD12 switch module and VMM6 control unit came configured to work with each other out of the box without any configuration. But, if you want to take advantage of advanced features, Maretron’s line of switching is managed through their G2Analyzer software connected to the vessel’s NMEA 2000 bus by either a Maretron USB100 or IPG100. This software gives you control of an impressive number of parameters for configuring both digital switches and the keypad or rocker switch controls. G2 Analyzer allows the user to configure what happens in response to a button push on a control device, what lights should be lit on the switches, how many amps a circuit should trip at, dimming, default state at power-on, flashing lights and so many other parameters.


Physical installation of the CLMD12 is pretty straightforward. A single 10-32v volt positive input connects to the stud at the top left of the switch, a ground is supplied to the ground conductor, and a NMEA 2000 drop cable is connected to the DeviceNet port on the bottom right of the switch. Once these basic connections are made the loads and controls can be configured. With those loads configured the last step is to connect the actual loads to one of the 12 wires coming out of the bundle of wires connected to the Deutsch connector on the bottom left side of the unit (labeled J1). I got everything connected and a couple of circuits controlled within an hour or so, though I lost some time because I connected a 5 amp load to a circuit preset to a 3 amp trip threshold. Once I realized this and adjusted the trip threshold everything worked well and I had the opportunity to verify the trip thresholds work as designed.

Bypass module

Maretron’s bypass module allows easy bypass of an entire switch module

In the event of a failed switch module, Maretron offers a bypass module for an estimated $195. The bypass module holds blade fuses for each of the 12 loads and also offers a mechanical on/off switch. Maretron’s intent is that a bypass module can be located next to each switch module or have one bypass handy for several switch modules. The bypass module comes with a short, 6 gauge, jumper to piggy back power off the switch module’s power supply. If the switch module fails, the 12-pin Deutsch connector, connected to J1 on the switch module, can be moved from the switch module to the receptacle on the bypass module.


A Maretron VMM6 with sample key caps

Maretron’s primary switch module for aftermarket applications is the VMM6, a six actuator (fancy word for switch) module with replaceable keycaps to match any label need. The $130 VMM6 will be available with multiple actuator configurations, the sample above has, from left to right, five momentary single action rockers and one double action rocker. The double action rocker effectively has two switches and can be used, as shown, to brighten or dim a light, but can also be used to control two separate loads. The action taken with each switch press is configured in G2Analyzer and includes toggling a load on or off when pressed, one button dimmer control –which toggles the load when tapped and dims up and down when held–, flash the load off and on, just dim, just brighten, momentary (only on when the switch is held), and several other possibilities.

CZone Contact 6 Plus

CZone’s Contact 6 Plus is a $250 6 circuit digital switching unit compatible with the full line of CZone digital switching and monitoring products. At about $42 per circuit the pricing is right in line with Maretron’s CLMD12 and also comparable to traditional mechanical switching. Each of the 6 circuits in the Contact 6 Plus can handle a maximum of 15 amps of 12 or 24 volt DC. The simpler Contact 6 Plus doesn’t have any of the discrete inputs or software configured trip thresholds of the Maretron switches. CZone has gone with a different circuit protection approach than Maretron or their own COI. The Contact 6 Plus uses physical ATC blade fuses for circuit protection and doesn’t have the ability to monitor current consumption. CZone’s use of physical fuses means you’ll need to keep spares on hand in case you blow one and also means access to the unit needs to be considered in order to replace fuses.

Contact 6 systems can be run as very small stand-alone switching systems with CZone’s Smart Harness. Smart Harnesses are available for two or three modules and are non-expandable NMEA 2000 networks. Out of the box Contact 6 systems come configured to run as a standalone system without other devices on their NMEA 2000 network.

If you’re going to use your CZone system with other NMEA 2000 devices on the network you will need to build a configuration in the CZone Configuration Tool and upload it to the CZone components on the network. The configuration tool is very powerful and makes it easy to configure an advanced system. Once the system is configured you can save the configuration file to an SD card and use an MFD to load the configuration onto the network. This ability is really nice as it means no additional hardware is needed to configure your system if you already have a compatible MFD onboard.


CZone Contact 6 Plus connection block

Installation of a Contact 6 Plus is also straightforward. The switch module accepts a single 12 or 24 volt DC positive input and a NMEA 2000 drop. The module draws ground through the NMEA 2000 connection. Loads are connected using a six pin plug-in screw terminal that accepts 8-24 gauge wires. Installation of the Contact 6 Plus took well under an hour but I had a bit more of a learning curve with the Configuration Tool so my time to successfully switching loads was similar to with the Maretron system.

Emergency bypass

CZone doesn’t use a separate bypass module, but instead there’s a secondary bypass position on each fuse holder. When the fuse is in the bypass position all digital switching circuitry is bypassed and a direct, fused connection is made between the power source and the load. There’s no additional expense for bypass functionality, but when compared to Maretron’s approach each circuit will need to be bypassed individually if the whole module fails.


A portrait 6 button keypad

CZone offers their keypad controls in six button ($220) and twelve button versions in both portrait and landscape orientations. When the Contact 6 Plus is operating in standalone mode with a smart harness, the push buttons can be configured to behave either as on/off toggle switches or as one button dimmers through a series of button presses. The labels on the panel are adhesive and the keypad comes with a sheet of 60 common labels. When the system is connected to a NMEA 2000 network and configured with the CZone Configuration Tool a much broader set of controls, like Maretron’s, are available.

Proprietary versus standard NMEA 2000 messaging

When manufacturers began designing their digital switching products the NMEA hadn’t added switching PGNs to the NMEA 2000 standard. As a result, manufacturers had little choice but to use proprietary messaging for their implementations. Since then the NMEA has modified the NMEA 2000 standard to include digital switching messages. Maretron has adopted those messages and operates on standard PGNs while CZone continues to use their proprietary messaging to control their switches. Within a single vendor’s system the use of standard or proprietary PGNs won’t change your experience with the products, but if you have multiple vendors’ equipment on the boat and hope to have it work together your options will be significantly better with NMEA 2000 standards compliant communications used.

Yacht Devices switching

So far we’ve talked about ambitious products with the potential to replace much of a boat’s DC distribution system. But, perhaps you’re looking for a simpler option to just control a few circuits. That’s where Yacht Devices‘ YDCC-04 circuit controller can come into play. First, a quick note that I own Yacht Devices U.S., the U.S. distributor of Yacht Devices’ parts. The YDCC is a 4 circuit switching device that takes a slightly different approach from Maretron and CZone.

The $250 YDCC is only an on/off device without dimming capabilities. Like Maretron it uses NMEA 2000 standard PGNs for all its control messages. It uses bi-stable relays to switch the circuits and these relays don’t have the ability to do PWM dimming. Additionally, the YDCC doesn’t take a single positive input and then distribute it, instead the switched leg is supplied for each circuit. The switched load can be AC or DC and nearly any voltage running up to 10 amps. The first two loads have outputs for when the circuit is on and off. This allows current to flow to one contact when the circuit is “off” and another when it’s on. There’s not any circuit protection in the YDCC so you’ll need it upstream of the module.

LED ringed momentary push-button switches connected to a YDCC on Have Another Day

But, the YDCC also has a full set of contacts on the right side of the device for switching. On Have Another Day I’ve switched several loads in my cockpit using a YDCC and what you see above are the four switches connected to the YDCC to control those circuits and indicate their status.

Yacht Devices also offers the $150 YDSC-04 which doesn’t include any relays but allows you to view and control the status of a YDCC (or any other NMEA 2000 standard digital switch) via switches and indicator lights.

Final thoughts

Digital switching isn’t just for new boats. Digital switching brings lots of benefits to your boat. If you’re taking on a project today that requires new circuits it’s hard for me to see why you wouldn’t use one of the low cost, high featured digital switching options in the market. This isn’t to say there’s not a learning curve with digital switching, because there is, but I believe the benefits I talked about earlier easily outweigh the differences and potential complexities. Anytime I look at new systems or paradigms on a boat I try and answer one question… Will this make boating better, easier or more fun? With digital switching I believe the answer is it can make boating easier and better, giving you options you simply can’t have with traditional mechanical switching.

This article was syndicated from Panbo


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