Electricity distribution

Ship electrical distribution devices are complete electrical devices in the form of switchboards (control panels) with control, protection and signaling appliances, designed to receive and distribute electrical power between consumers.

Ship electrical distribution devices are classified according to the following main features:

a) on purpose:

1. the MAIN one, designed to connect sources of electricity to the ship's power network, control their operation and distribute electricity;

2. EMERGENCY, which is part of the ship Emergency Electrical Plant and designed to connect emergency sources of electrical energy to the emergency network, control their operation and distribute electrical power;

3. GROUP, designed to distribute electrical power between a group of consumers of the same purpose;

4. a CONSUMER’S SWITCHBOARDS, designed to supply electrical power to a separate consumer, as well as control its operation;

5. power supply FROM SHORE, designed to connect the ship's electrical network to the shore electrical network or the network of another ship;

6. GENERATOR, designed to transmit electrical power from the Generator (G) to a certain Main Switchboard (MSB), as well as for local control of the Generator in cases where the Generator and Main Switchboard are located in different compartments of the vessel (separate power consumers can receive power from the Generator Board (GB));

7. CONNECTING ELECTRICAL BOX, which is a ship's electrical switchgear designed to connect electrical circuits;

8. SIGNALLING AND CONTROL, designed to give signals (sound, light) about the state of controlled premises, installations, systems, electrical systems and other objects.

b) by the location on board ship:

1. REGIONAL, intended for the distribution of electrical power within a certain architectural area of the ship and providing power to several cut-off electrical boxes;

2. CUT-OFF, intended for the distribution of electrical power within the single compartment of the vessel.

c) by design into FRAME and BLOCK TYPE. Electrical boxes in a frame design are usually made according to individual drawings, which complicates their production and increases the cost. If necessary, separate block boxes can be used to complete switchboards of any size and for any scheme.

d) according to the degree of protection from the environment, PROTECTED (IP21), SPLASH-PROOF (IP23) and WATERPROOF (IP55) switchgears are distinguished. Cables are entered into splash-proof shields from below through holes with frames that prevent damage to the cable sheath, and into waterproof switchboxes - through individual or group electrical glands.

e) according to the type of current, of DIRECT and ALTERNATING, 1- and 3-PHASE CURRENT are distinguished;

f) according to the presence of switching and protective equipment, all switchboards are divided into 2 types: WITHOUT SWITCHING DEVICES and WITH SWITCHING DEVICES.

The switchboard without switching devices contains only fuses of the DC and AC types. Such switchboards are used on small boats.

Typically, distribution boards with switching devices are of two types:

1. with batch switches and fuses;

2. with automatic switches (automatic circuit breakers ACB).

Distribution boards of the first type, as a rule, are not used to power 3-phase Electric Motors (EM). This is because when a fuse blows in one phase, a 2-phase mode of operation of the EM sets in, followed by its overheating and failure. At the same time, the operation of the Automatic Circuit Breaker ACB, due to a short circuit in any phase leads to a complete disconnection of the Asynchronous Motor (AM) from the supply network.