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240 Volt Installation
Many clients wish to enjoy more home comforts while cruising. JDBS has considerable experience in this area and can advise on the best solution to individual clients problems.

Energy Audit


We advise clients to make a list of those electrical appliances they wish to use. JDBS can then advise on the most effective solution and discuss their relative costs.


It is worth remembering that there are limitations on what can be reasonably provided within a boat. Very few Shoreline sockets can provide more than 16 or 20 amps, this roughly equates to between 3 and 4 Kilowatts and that is a tiny proportion of your electrical provision at home. For most boats the main serious problem is a washing machine, particularly if some form oif tumble dryer is required.


Where an Inverter is chosen, a common misconception is that a large bank of batteries is essential. There are many different types of batteries available at prices varying from modest to extremely expensive, opinion will vary regarding which is the most suitable for boat use. Our own belief is that it is preferable to choose a smaller number of better batteries. While a reasonable reserve is needed there will rarely be much advantage in exceeding a total of 600 Amp Hour if the batteries are to be recharged properly, whether by engine alternator or external mains chargers (the better solution). A fairly common battery to be found on a boat is 12 volt 90 Amp/hour, in theory one such battery could run a 1Kwatt appliance for 1 hour, in reality it probably won’t. If the only means of recharging batteries is by running the boat engine it will take something like 5 hours to achieve less than 100% charge, a full charge cycle of 24 hours is more like the time needed but not really achievable. Doubling the number of batteries is only a short term solution, it merely means running your engine for at least twice as long to recharge them, in practice it takes more than twice the time. The plain fact is that boat batteries are rarely properly charged which is the reason for so many premature failures.Effective solutions to most problems can be found but there are sensible limits and the cost rises dramatically as expectations increase.

There are three main ways of providing a "mains supply", each has advantages and disadvantages

 1. Shore Line

This is the cheapest solution, but is obviously not much help if a Shore line socket is not available at the clients moorings, also very few shore line sockets will be available while on holiday. Thought should also be given to the additional requirements of the EC Recreational Craft Directives which became mandatory for all new boats from June 1998, this legislation is not retrospective but British Waterways are adopting some of these requirements for Safety Standards Certificates. A 2 pole Isolation Switch, Phase Polarity Indicator and a warning label is required explaining their operation. A Residual Current Device and individual Circuit breakers for each boat circuit is also a requirement, but this is good practise and JDBS would always fit one.
 2. Inverter

JD Boats are distributors for Victron inverters.

Inverters are now available in a wide range of prices, quality and power output. Better manufacturers are now offering models providing high degrees of reliability and good protection to increasingly sophisticated domestic equipment, most of which has some form of electronic control. Some inverters are also combined with battery chargers which can be used in conjunction with a Shore line or good generator. Installation is usually relatively simple, particularly when internal wiring and sockets have already been installed. Apart from the cost of an Inverter a restriction is the limited amount of power stored within boat batteries and the time needed to recharge them.


 3. Generator

These fall into 3 main types:-
Petrol, Diesel and LPG portable generators
Propulsion engine driven 240 volt Alternators
Stand-alone Diesel Generators
Petrol, Diesel and LPG portable generators

Problems here are petrol storage (where applicable), moving them around (if powerful enough to be useful they are very heavy), noise, fumes and vulnerability to theft.

Noise levels in particular can be very annoying to other boat owners or residents of houses near the canal. The only advantage is their relatively small cost.


Propulsion engine driven 240 volt Alternators

Some of these have been unreliable in the past and have also caused problems to electrical appliances due to their inherent lack of voltage and cyclical stability. New models are much improved but still mean that noise and vibration levels can be intrusive if owners need to use them while tied up, wear and tear to the main engine is inevitably accelerated since Diesel engines do not like working against light loads. An apparently relatively cheap and effective solution to the “washing machine problem” does have disadvantages and thought should be given to longer term problems.


Stand-alone Diesel Generators

These are usually a semi-permanent installation being enclosed (cocooned) in sound deadening enclosures and double damped to reduce vibration, exhaust systems can be designed to reduce noise levels to a minimum, causing less annoyance to the boat owners and their neighbours. Not surprisingly, this is a much more expensive option and also not without its problems.