Safety First, Second and Third

We approach this subject with a HUGE caveat. If you are in any way unsure of your abilities in this area then seek the advice of a professional.

Much information exists on the subject of marine AC systems and it is easy to become confused.

We are dealing with lethal quantities of electricity in conjunction with large chunks of conducting metal and water. Water is especially dangerous where stray currents are involved. The impurities and ions found in the waters we play on make it a good conductor of electricity, the nature of water enables a greater surface area contact with the skin than, say, an individual strand of wire.

In any case, ALL installation work must be done to comply with the Recreational Craft Directive & the Boat Safety Scheme. These measures are in place to ensure the safety of all persons involved in enjoying this way of life and should not be negotiated with!

If you have purchased a basic sailaway canal boat which requires a full electrical installation, always employ the services of a professional.

Sources of AC Electricity

As we have seen, it is possible to produce 230VAC electricity on a narrowboat by inverting power from a bank of DC leisure or “house” batteries. AC electricity can also be supplier from a generator, whether this be an engine alternator type, fixed or portable.

In this context however, we are discussing stand alone 230v AC power brought in to our narrow boats from the shore based mains power systems, the same systems we are used to in our homes. Therefore we will define this type of 230v AC power as Shore Power.

The most basic system will consist of a power inlet plug. From this a 3 core cable will carry the live, neutral and earth wires to a RCD/MCB distribution box also known as a consumer unit.

Before the earth enters the consumer unit it is good safe practice to “bond” it to the hull of a steel narrow boat. The presence of RCD’s protecting 230v AC circuits is a requirement of the Boat Safety Scheme and this will be checked by your examiner.

From the consumer unit the cable will continue around the boat to sockets etc as required. We would recommend the use of 2.5mm square Acrtic Blue 3 core multi-strand cable (or equivalent) for all connections to shore and also for internal AC wiring.

Electrical Supply Sockets

The majority of electrical feeds from UK marinas and other moorings will be 16 amp and use the industrial circular blue plugs (used for most leisure pursuits such as caravanning). Some of the newer marinas are beginning to provide a 32 amp supply, if this is the case, will use a similar type socket but of a larger type for accommodating the 32 amp feed. Please check with the marina / mooring management which type of socket they use.