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Hi. I am an recently retired industrial electrician, I am worried about an installation in my own home I did about 30 years ago. I supplied my burglar alarm control box. By Spuring off my ring main (unfused) about 4 feet to the alarm box. I may also have down sized the cable to 1.5mm T&E. I did not fit a fused Spur on the supply as the Alarm box is fused internally on the supply as it enters the box. At the time I thought this was O.K. as I understood the 3 meter rule to allow Down sizing and omiting of a fused spur at the point of connection to the ring main. As long as the run was less than 3 meters and the load to be suitably limited by protection at the end or along the supply cable. Since retiring I have had time to ponder these things. Any clarification would be a big help.
 
as he said^^^^^. normal practice is to fit a unswitched FCU (3A) adjacent to the alarm panel. but it's not unsafe. it's worked for 30 years ain't it?
 
must taken a long time to think about it. or was it a light bulb Moment .:rolleyes:

He might have only been retired for 1 day..
 
At the time I thought this was O.K. as I understood the 3 meter rule to allow Down sizing and omiting of a fused spur at the point of connection to the ring main. As long as the run was less than 3 meters and the load to be suitably limited by protection at the end or along the supply cable.
I thought you could only apply that rule for connections within 3M of a cutout/meter or busbar chamber, not parts of a final circuit?
 

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