Hi there
I have a few questions related to the power ratings of certain devices and how this interplays with the fuse. The reason I am asking this is whether I can safely add new plug sockets off an existing 3A fused spur (I plan to only use these plug sockets for low power devices).
The current 3A fused spur is connected to a Heatmiser wiring centre which controls our wet underfloor heating system. The wiring diagram of the Heatmiser wiring centre is below and my queries relate to the yellow highlighted sections.
1. Given Power (P) = Current (I) x Volt (V), if the power consumption is 7W and the supply voltage is 230V, wouldn't that mean the current the unit consumes is 0.03A (i.e. 7/230) or, if not, please can someone explain?
2. If I am correct in concluding the current consumed is 0.03A, why is there (a) a 3A mains supply fuse (this is in a 3A fused spur) and (b) a 5A fuse on the board? How much 'excess' fuse capacity is on the 3A fuse if the Heatmiser wiring centre is the only device connected to it?
3. If I am correct in concluding the current consumed by the Heatmiser wiring centre is 0.03A, how can the max load on the different boiler/H/W/zone outputs be 3A 230V with a max total load of 5A?
4. Would it be safe to run a couple of plug sockets coming off the 3A fused spur (I would want to use low power devices)? If so, how much spare "ampage" should there be for those plug sockets (would it, for example, be 3A less 0.03A)?
Thank you in advance
I have a few questions related to the power ratings of certain devices and how this interplays with the fuse. The reason I am asking this is whether I can safely add new plug sockets off an existing 3A fused spur (I plan to only use these plug sockets for low power devices).
The current 3A fused spur is connected to a Heatmiser wiring centre which controls our wet underfloor heating system. The wiring diagram of the Heatmiser wiring centre is below and my queries relate to the yellow highlighted sections.
1. Given Power (P) = Current (I) x Volt (V), if the power consumption is 7W and the supply voltage is 230V, wouldn't that mean the current the unit consumes is 0.03A (i.e. 7/230) or, if not, please can someone explain?
2. If I am correct in concluding the current consumed is 0.03A, why is there (a) a 3A mains supply fuse (this is in a 3A fused spur) and (b) a 5A fuse on the board? How much 'excess' fuse capacity is on the 3A fuse if the Heatmiser wiring centre is the only device connected to it?
3. If I am correct in concluding the current consumed by the Heatmiser wiring centre is 0.03A, how can the max load on the different boiler/H/W/zone outputs be 3A 230V with a max total load of 5A?
4. Would it be safe to run a couple of plug sockets coming off the 3A fused spur (I would want to use low power devices)? If so, how much spare "ampage" should there be for those plug sockets (would it, for example, be 3A less 0.03A)?
Thank you in advance