Shore to Boat Mains Supply
Over the years I have been called out to cure all sorts of installation problems on narrowboats frequently the boats electrical installation started as one system and over the years has evolved with changes and modifications that the final system is often very complicated unreliable and in many cases downright dangerous.
There really is no need for this, if a logical approach is taken to the installation. Shore supplies ar invariably mains voltage at 230 volts with most rated around the 16 amps.
There really is no need for this, if a logical approach is taken to the installation. Shore supplies ar invariably mains voltage at 230 volts with most rated around the 16 amps.
When it comes to a shore supply, it really depends if you are based at a marina using mains all the time, or if it is for occasional use only. I am a constant cruiser and only use a shore supply to top up the batteries on occasions. many permament mooring boaters use the shore supply for mains appliances such as washing machines as well.
But whatever you use the supply for, the first thing to consider when installing a shore supply as the installation of a Galvanic isolator or isolation transformer.
When you connect your boat to a marina electrical supply you also connect your boat to all the other boats in the marina via the earth connection in your shore power mains lead. This creates a pathway for small electrical currents to flow from one boat to another. Unfortunately this pathway leads to increased corrosion of the underwater metals and results in rapid loss of anodes and increased pitting and deterioration of hulls, propellers, shafts, outdrives etc. you can protect against this problem by installing a galvanic isolator.
When you connect your boat to a marina electrical supply you also connect your boat to all the other boats in the marina via the earth connection in your shore power mains lead. This creates a pathway for small electrical currents to flow from one boat to another. Unfortunately this pathway leads to increased corrosion of the underwater metals and results in rapid loss of anodes and increased pitting and deterioration of hulls, propellers, shafts, outdrives etc. you can protect against this problem by installing a galvanic isolator.
Many boaters have an inverter for use when away from the mooring and shore power for use when in the marina.
This can complicate matters in that some means to switch between the two is required.
There are probably more ways to achieve this than there ways to skin a cat, the most basic method is to have a plug feeding the boat electrical system which is simply plugged into shore power or the inverter. This is far from ideal. Usually a more permanent solution is sought.
One possible problem that has to be guarded against any possibility of shore power finding it's way to the output of the inverter.
This in nearly all cases, totally destroys the inverter, instantly, whether or not it is switched on. For this reason both the Live and the Neutral have to be switched. Also "break before make" switches must be used.
This can complicate matters in that some means to switch between the two is required.
There are probably more ways to achieve this than there ways to skin a cat, the most basic method is to have a plug feeding the boat electrical system which is simply plugged into shore power or the inverter. This is far from ideal. Usually a more permanent solution is sought.
One possible problem that has to be guarded against any possibility of shore power finding it's way to the output of the inverter.
This in nearly all cases, totally destroys the inverter, instantly, whether or not it is switched on. For this reason both the Live and the Neutral have to be switched. Also "break before make" switches must be used.
This method uses a manual change-over switch to select between shore power and the inverter. It is simple and reliable. The only downside is that it requires user intervention to select between the two, saying tha it doesn't seem to bother many people.
