|SINGLE PHASE||THREE PHASE|
|A circuit breaker operating in all live conductors of the supply, with the neutral conductor to open circuit when tripped and to be fitted adjacent to the shore supply inlet on the vessel.||A circuit breaker operating in all live conductors of the supply, with the neutral conductor to open circuit when tripped and to be fitted adjacent to the shore supply inlet on the vessel.|
|A test device, connected on the supply side of the vessel’s shore supply circuit breaker to check, and visually indicate, the polarity of the shore supply in relation to the vessel’s system. *||A test device, connected on the supply side of the vessel’s shore supply circuit breaker, to check and visually indicate the polarity of the shore supply in relation to the vessel’s system.|
|An interlocking circuit to ensure the shore power cannot be connected unless the polarity is correct. *||A means of checking the phase sequence in relation to the vessel’s system.|
|Indication to show when the shore supply is energised.||An indication to show when the shore supply is energised|
|Appropriate switchgear to facilitate the reversal of polarity.||Appropriate switchgear to facilitate the reversal of phase sequence|
|An interlocking circuit to ensure the shore power cannot be connected unless the polarity and phase rotation are correct|
* Except where shore power is supplied to the boat by an on-board isolating transformer or converter with a polarized output
Shore connections of single-phase and 3-phase installations for berthed Pleasure Craft and DCV (NSCV) vessels at wharfs/jetties/marinas, are to comply with requirements detailed within AS/NZ 3004.2:2014 – Electrical Installations-Marinas and Boats; Part 2: Boats.
SET Maritime & Electrical has been involved in the Domestic Commercial Vessels (DCV) over the past 6 years, specialising in electrical compliance for Plan Approval and Surveys of vessels. In this time a range of different shore connection installations has been inspected and checked against the required Standards. In most cases full compliance has not been met.
The most critical safety factor for a vessel is Reversed Polarity which presents a very serious risk of electrocution. This occurs when the Active (red) and Neutral (black) electrical wires are reversed. The vessel’s wiring is correct for Polarity, when this is verified by a Certificate of Electrical Compliance and is issued by an Electrical Contractor. The issue is that at each time a connection is made, the Polarity of shore connections are unknown to the vessel owner, due to unknow maintenance or interference. If polarity of the power supply is reversed, this then will render the vessel’s electrical safety devices ineffective.
The shore connection products available on the market, are all based upon a Polarity Monitoring Device to detect reverse polarity with a simple circuit shown below as the fundamental design of them all.
With the large variety of interpretations on how the mandatory functional requirements for shore connections are met, that have been detailed above, the process involved in monitoring for correct Polarity, is to have functional earthing (FE) permanently connected. This is undertaken to ensure the correct operation, rather than for the safety conditions associated with protective earthing. The combination of both protective and functional earths are required, as per AS/NZ 3000:2018 – Wiring Rules, and it should be noted that FE does not offer protection from electrocution from a hazardous voltage.
SET Maritime & Electrical have designed an installation called the “Shore Connection Box”, that meets the safety functionality detailed within the Standard for single-phase and three-phase electrical installations.
For the Polarity Monitoring device, the Functional Earthing (FE) circuit makes only a momentary connection to check polarity and allows for the interlocking contactor to allow for supply to the vessel. Upon completing the test, it is will disconnect the circuit, thereby reducing the risk of electrocution from a hazardous voltage.
There are 3 versions available:
Patent No: 2020100761
Two versions have been designed:
The circuit design has been designed to be fail-safe, in that if the polarity has been changed, then automatic reconnection cannot occur. Both versions come with reverse polarity change over switch
The 3-phase Shore Connection Box enclosure has been designed to automatically monitor the incoming power supply, and once the enclosure is energised, the Monitoring Relay will detect the Phase Rotation, Loss of Phase, Under Voltage and Over Voltage.
The circuit design has been designed to be fail-safe and will re-test the incoming power supply prior to restoring power.