This weekend we worked with two separate events who contacted us to hire emergency Event Power due to problems with the 400v static supplies on their sites. Our electrical technicians were called out yesterday to rescue circa 100 food traders requiring power for catering, card machines, hot drinks, lighting and all important refrigeration. For those that may be ofay with 400v three phase the picture of several 400v sockets turned out to be more deceiving than first thought. Steve our electrical engineer reported that two of 63amp sockets had a label say they couldn't be used together. One 63amp was 4 pin, the other was 5 pin. The 32amp and 16amp 400v sockets were also 4 pin. We called Janet at Distribution Zone who told us we were dealing with an obsolete pin system rarely used in 2018 commercially.