You know the routine: boats tie up to the jetty and right after the mooring lines, the shore power cable comes out. This is no different in Finland. So here is your compact guide to shore power in Finnish marinas.
Electricity in Finland
Finland uses 230V, 50 Hz electricity like most of Europe. So the first thing to check when sailing to Finland is that your shore power system is rated for that voltage. If your boat is not set up to use 230V and 50Hz electricity, then just using the adapters will not help you. For more information on the implications of the different voltages and frequencies, check for instance this article by s/v Woosh.
Shore power plug or adapter
In general, Finland uses the so called Schuko plugs. For a long time, the Schuko plug with protective earth was the dominant plug for shore power outlets that you found in Finnish marinas.
Later, the regulations were changed and new installations were required to use connectors and plugs specified by the IEC 60309 system for industrial use (I will call this type of plug IEC). As most shore power outlets are two-phase and the voltage is in the 200-250V range, the actual plug to be used is the blue P+N+E connector (3 pins, power + ground + protective earth). Note that purple, white and yellow connectors should not be used as they are rated for lower voltages.
Marinas with existing shore power installations were however not required to upgrade to the IEC connectors and many marinas still use the Schuko type outlets. This means that your boat needs to have plugs or adapters that can connect to either of the two outlets. Often this is done so that the main power cable to the boat has the Schuko plug and then this cable to connected to the IEC outlets using and adapter or adapter cable that provides a female Schuko plug. Of course you can do this the other way around too: IEC cable and an adpter from IEC to Schuko.
Shore power capacity
How much power you actually can draw out of the shore power outlet will vary. Some of the older installations have a number of outlets connected to a single fuse, often 10A or 16A most. In these cases, the system is mainly intended for charging your boat’s batteries, running your computer or a hair dryer. 1-3A current per boat would be a good norm but there is really no way of knowing how much current you can use. More power hungry equipment is quite likely to blow a fuse.
Modern marinas have much higher specced systems and individual boats can draw the full current permitted by the fuse, typically 10A or 16A. You can easily find the fuse rating, it is written on the automatic fuses of modern installations, just peek inside.
If you have a monster boat that draws power like a small village, then you need to check with the marina if there are special outlets available that can handle your power needs. Normally these would be three-phase outlets providing a voltage of 380V.
In many small marinas out in the archipelago, not only is the current capacity limited, but also the number of electrical outlets is often much lower that the total number of boats that the marina can accommodate. It’s considered bad behavior to unhook someone else’s electric cable so you need to have a plan B.
For these marina it is good to carry a two-way splitter (typically Schuko male + 2 x female) so that you and your neighbor can share the same outlet. If the owner of the other boat is not around, then you can intermittently disconnect him and then reconnect both of you with the splitter.
Remember though that both boats are now hanging of the same fuse so if the fuse blows, then you, your neighbor (and a varying number of boats around you) will lose power.
Edit: I had forgotten to mention that you can of course build the splitter system also “in reverse”: 1) IEC cable to the boat, 2) IEC-to-Schuko converter to connect the IEC cable to the old Schuko-type outlets and 3) an IEC splitter. Thank you David for you comment that made me notice the omission.