Switch for every 12v item?

[SteveTibbetts]

I will need to consolidate the 3 separate switch panels on my boat into 1 at some time. I really don't want to be looking for switches down below while there's a port entry to be negotiated. We currently have a dogs breakfast of wiring and it looks like a previous owner did have the idea that each and every piece of equipment needed a switch, albeit in one of 3 places.
There are currently over 20 switches spread over the 3 panels, some with adjacent fuse holder and some with an in-line fuse behind the panel.
I intend to replace with an 8(?) switch panel with surface mount fuses.

I believe that best practice would be to have items such as VHF, plotter, chart light, etc unswitched and available whenever the boat is in use, everything being the right side of the 1-2-both isolator switch. Modern electrics items all seem to have a functioning on/off switch.

Sound right to you?

 

[MoodySabre]

Personally I would like everything fused. If something blows, particularly on the nav/VHF side then I wouldn't want to loose everything.
Sometimes it is necessary to double up to simplify switching.

 

[prv]

Every run of cable needs to be protected by a suitably sized fuse, but I agree that not everything requires a switch on some central panel if you have a master isolator and a local means of turning the item on and off.

For my new wiring on Ariam I will have a fusebox behind the chart table panel, with nearly everything powered from this. The exceptions are the fridge and the bilge pump, which would need a diversion several times longer than the rest of the circuit just to go up to the fusebox and back down again - instead these will have their own fuses near the batteries. Then, after the fusebox, some of the circuits will have a switch on a central panel, others will not. The switched ones are those I'm likely to want to turn on and off while using the boat:

• Instruments - I turn this off at the end of a day's sailing, once tied up
• VHF / AIS - Ditto. Turning off at the VHF's own switch is no good as the circuit also powers a GPS puck I want turned off along with the radio. Plus having to turn off both VHF and the AIS display separately in different places is more hassle than flipping one panel switch.
• Plotter / Radar - I might want this on or off depending on what we're doing.
• Chart Nav - this is the panel name for the circuit powering the Yeoman plotter and Garmin basic GPS. I will often want this on, my parents will not as they're confirmed plotter-philes.
• Navtex - On a multi-day trip I would want this left on overnight while the other instruments are off; on a daysail I wouldn't turn it on at all.
• Cabin lights - I ummed and ahhed over whether to have a master switch for this. But decided it's useful to be able to turn all the lights off in one go when leaving for the pub - and ensuring that nothing is on and wasting power during the day. I've fitted a small, dim LED next to the switch to find it in the dark when returning from said pub
• Water pumps - freshwater and shower sump pumps. Might be turned off at night to avoid noise from re-pressurising the system.
• 12v and USB sockets - actually I can't remember why I decided to switch this one now! But the panel has already been laser-engraved, so it's staying

Various other things have no switch on the central panel:

• Nav lights - have their own waterproof rotary switch in the cockpit
• Fridge - has a hard on/off switch on its control panel in the galley. Controller, compressor and batteries are all in close proximity - extending the cables up to the panel and back would be needless complication.
• Bilge pump - Similar reasoning re cabling, plus I never want to turn it fully off - float switch active at all times unless the fuse is pulled for maintenance.
• Anchor windlass - not the heavy power feeds, but the current to the control buttons, wireless receiver, relays, etc. This is isolated by a waterproof switch in the cockpit so that dangerous accidental operation can be avoided.
• Deck lights - again have a switch in the cockpit and no need for one on the panel below decks
• Deck power sockets (cockpit and foredeck) - switched in the cockpit, nearer to where they are used.
• Stereo - has its own power buttons on main unit and remote. See no need for a panel switch, plus mildly inconvenient to have to go below to turn it on rather than just pressing "On" on the cockpit remote.
• Eberspacher - must not be turned off while running, so having no panel switch is safer.

Pete

 

[Buck Turgidson]

Divide the users up by function/priority and put them on a combined bus with bus master switch. e.g.

Comms Bus(This is powered whenever you are sailing)
- VHF
- AIS
- associated GPS
- Navtext

NAV Bus ( May or may not be powered when sailing)
- Chart Plotter
- associated GPS
- Instruments

Lights Bus ( Only used at night)
- All Nav lights
- Compass light
- Chart table light

Domestic Bus (May be used at any time)
- House lights
- Other systems

By isolating each bus you can use bus master switches and shorts on one bus wont effect the others.

An alternate idea would be to divide into Emergency (comms and nav lights) Essential (instruments and Plotter) and Non Essential ( all the other) equipment. This is how it's done on commertial aeroplanes.

Using seperate busses means you can use the equipments on off switches rather than additional panel switches and only have panel switches for the busses. Everything still needs to be fused (I prefer CB's) individually.

 

[nigelmercier]

With the exception of the lighting, and the chart plotter (which is on the Instruments switch) my philosophy is ...

If something has a switch, it doesn't need another one.