My garage contains a radial socket circuit, wired with 2.5mm T&E and protected by a 16A MCB.
This circuit also feeds a 3A FCU which powers my burglar alarm. I need a mains socket near this and there's no other practical way of getting a new cable to it without removing a tiled floor, so I'm hoping to use the feed to the FCU to also connect a socket.
I've found that the cable to the FCU isn't 2.5mm - the external dimensions of the cable mirror that of 1.5mm T&E however having removed the FCU the insulation of the inner cores looks more like 1.0mm than 1.5mm. I haven't yet turned the power off to measure the actual cores but either way it's no bigger than 1.5mm.
The cable to the FCU runs under an uninsulated suspended floor so can I assume reference method C for the cable? If so, am I right in thinking 1.5mm is rated to 20A and 1.0mm to 16A, therefore given the MCB is rated at 16A I would technically be fine to extend the circuit to another socket using either 1.5mm or even 1.0mm, even though this isn't normally used for sockets?
If that's not acceptable, I assume it'd be fine to install a 13A FCU at the garage end of the existing cable, thus protecting the cable to the existing 3A FCU for the alarm and also the socket I intend to install? I don't anticipate using this for high power devices so I'd be happy to fuse at 10A or even 5A however I'd rather allow for other people plugging in devices such as a vacuum cleaner that could blow this fuse which would also knock out the power to the burglar alarm.
This circuit also feeds a 3A FCU which powers my burglar alarm. I need a mains socket near this and there's no other practical way of getting a new cable to it without removing a tiled floor, so I'm hoping to use the feed to the FCU to also connect a socket.
I've found that the cable to the FCU isn't 2.5mm - the external dimensions of the cable mirror that of 1.5mm T&E however having removed the FCU the insulation of the inner cores looks more like 1.0mm than 1.5mm. I haven't yet turned the power off to measure the actual cores but either way it's no bigger than 1.5mm.
The cable to the FCU runs under an uninsulated suspended floor so can I assume reference method C for the cable? If so, am I right in thinking 1.5mm is rated to 20A and 1.0mm to 16A, therefore given the MCB is rated at 16A I would technically be fine to extend the circuit to another socket using either 1.5mm or even 1.0mm, even though this isn't normally used for sockets?
If that's not acceptable, I assume it'd be fine to install a 13A FCU at the garage end of the existing cable, thus protecting the cable to the existing 3A FCU for the alarm and also the socket I intend to install? I don't anticipate using this for high power devices so I'd be happy to fuse at 10A or even 5A however I'd rather allow for other people plugging in devices such as a vacuum cleaner that could blow this fuse which would also knock out the power to the burglar alarm.
