I am running a permanently switched live loft cable from a landing light switch which previouslly used to feed the loft light as well (two way two gang switch originally) to a junction box in the loft, which then feeds to a socket to power a 3amp power supply for the aerial and another junction wire to a one way gang switch forthe loft light. Should I put in a fuse before the junction box to meet regs or is this no possible?