This 1600A Dorman Smith CB has stood guard over a switch board for around 35years without, as far as I know, anyone going near it. I suppose I should ask DS but
anyone know what service arrangements, if any, that it should be subject to?
Sound advice indeed Geoff! There is, as you rightly suspected, a generator feed in. The switchboard would require to be completely isolated to add or remove other protective devices as it comprises bare busbars immediately accessible on the removal of any cover section. The installation is in a large cold store and the device in the photo can be operated when ammonia is detected in the adjacent compressor plant room. I don’t know why this was done as there is a separate MCCB serving the MCC in the compressor plant room and the alarm output could have been connected to either end of that. As it stands, I backed out of running a test on the alarm as I feared the device would not re-set. This happened in another plant when the alarm activated on a real gas escape and the main MCCB would not reset. We were in danger of loosing hundreds of thousands of pounds of frozen goods so you can imagine the panic in trying to get things back on line. It is the same company so obviously they are not up for learning lessons!
Sound advice indeed Geoff! There is, as you rightly suspected, a generator feed in. The switchboard would require to be completely isolated to add or remove other protective devices as it comprises bare busbars immediately accessible on the removal of any cover section. The installation is in a large cold store and the device in the photo can be operated when ammonia is detected in the adjacent compressor plant room. I don’t know why this was done as there is a separate MCCB serving the MCC in the compressor plant room and the alarm output could have been connected to either end of that. As it stands, I backed out of running a test on the alarm as I feared the device would not re-set. This happened in another plant when the alarm activated on a real gas escape and the main MCCB would not reset. We were in danger of loosing hundreds of thousands of pounds of frozen goods so you can imagine the panic in trying to get things back on line. It is the same company so obviously they are not up for learning lessons!
