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Any similarity between an EVC point and a socket for a refrigerated cargo container?

Unless things have changed since I retired in 2002, I am curious regarding the similarity between an EVC point and a socket for a refrigerated cargo container.


On board ship, refrigerated cargo containers were simply plugged in to the ships electrical system. 3-phase, 3-wire plus earth, so a 4-pole plug and socket. The acceptable voltage being 380 to 460v 60 or 50 Hz. Most ships being 60 Hz, but some I sailed on had been designed for possible MOD charter and were 50 Hz. (there were some dual voltage containers, ie for 3-phase 230 volt supplies which some ships had.)


The lowest power consumption was for frozen cargo, whereas cargo which was carried chilled or even warm, due to fresh air requirements rather than recirculation, resulted in higher power consumption.


Considering that the container was connected via 10 metre or so cable, this looks similar to an EVC connection?  In rough weather, I have experienced heavy seas over the deck causing cables to be ripped out at the container end and when the weather subsided, I found that the doors of a container full of French Fries were having some cooked on deck by a fizzing broken cable.


Circuit protection either three cartridge fuses or a MCB, never came across any RCDs. Some ships fed the sockets directly off the main 440v bus, so an earth fault on a container, usually the defrost heater, would show as an earth on the ship's main 440v bus, other ships had the luxury of a number of isolating transformers. A quick Google tells me that some ships can carry 500 refrigerated containers, some more. This explains why my last ship generated at 6.6 kV.


Containers held on the quay side were plugged into pillars and I guess the same for when containers were at their destination, or awaiting stuffing. I never saw one of these in those days https://catalog.eslpwr.com/wp-content/pdfs/s_3500-02.pdf but certainly looks serious.


Yet the requirements suggested in  http://digitalfizz.com/cargostore/wp-content/uploads/Reefer_Power.pdf of RCD protection and under volt release, seems less stringent to that for a EVC point?


Clive

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  • Thanks fd from the for that Graham, I`m still digesting your comments.

    As an aside, a couple of years back I did an install on farm grounds fed from the farmhouse. The farm itself was fed from a pole pig in the next field say 20 metres away. It was the only customer on that Tx. Two wires (single phase) to the farmhouse and the N was split to N & PE in the service head and had an earth rod in the garden just where the supply entered the external wall then to the head. I decided it was TNC-S but perhaps it was TNS (PNB) ?
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  • Thanks fd from the for that Graham, I`m still digesting your comments.

    As an aside, a couple of years back I did an install on farm grounds fed from the farmhouse. The farm itself was fed from a pole pig in the next field say 20 metres away. It was the only customer on that Tx. Two wires (single phase) to the farmhouse and the N was split to N & PE in the service head and had an earth rod in the garden just where the supply entered the external wall then to the head. I decided it was TNC-S but perhaps it was TNS (PNB) ?
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