Posted By Paul Leadbetter Alan A fuse is designed to break a circuit when it experiences a sudden increase in current above its rating. When current is increased stepwise, it is possible to exceed the fuse rating by quite a margin without it blowing. With daisychaining of extension boards, it is easily possible to get the total current well above 13 amps (a few amps here and a few amps there soon adds up); the consequent heating of the plug and lead increases the risk of fire. If you leave everything connected to the extension boards turned on but switch off the wall socket, you may find that the fuse blows when you turn it on again because, in this case, the high current is applied all at once and so the fuse does its job. Paul

Posted By MichaelM Alan I found something similar recently and instructed them to stop the practice immediately. An extension should not be plugged into another extension in any circumstances as this leads to overload if all plug socket availability is used. It was a four gand into a four gag going to the right and a four gang into a four gang going to the left, allgoing into a double wall socket! Dangerous practice! Michael