If you are thinking about buying and installing electric blinds, then it is important to plan ahead to ensure you have the right power supply, connections and cabling in place to supply your blinds with power. One of the questions we are frequently asked by our customers is "what size of fuse do I need for electric blinds".
The questions we are going to answer in this article are:
For the purposes of this article we will consider 230vAC radio operated roller blinds with Somfy Sonesse 40 RTS or Newblinds Radio motors, because these are connected directly to the mains power. When we talk about radio operated blinds we mean blinds controlled wirelessly by some form of radio controller - this might be a handset, wireless wall switch or a centrat hub system such as Somfy TaHoma or Louvolite One Touch Hub.
So starting off with the basics, it's important to understand exactly what a fuse does.
Fuses should be used with every electical device that uses mains power - an example being a mains powered blind motor! Fuses serve to protect the wiring and the device. The fuse contains a thin piece of wire that melts easily. If for some reason the current going through the wire within fuse is too great, the wire within the fuse heats up until it melts and breaks the circuit, stopping power to the cabling and the device, before they overheat or get damaged!
When discussing fuses, you might typically think about an occasion in the past where you've had to replace a fuse on a house-hold appliance. These days house-hold appliances tend to come come with plug-tops and fuses pre-fitted. The fuse would be easily removable, by either unscrewing the plug casement, or it would be stored in a removable chamber.
It's a little different with mains powered electric blind motors. Plugs are typically pre-fitted to portable appliances and devices (e.g. lamps, kettles, toasters etc) whereas a blind, once installed, remains in situ and is not portable. For this reason, the power cable of the mains powered electric blind motor that we supply do not come fitted with a plug or fuses. When planning for installation of mains powered blinds, it is normal to connect the blind cable directly to a switched fused spur. Installation of the fused spur and connnection of the blind to the fused spur would normally be carried out by an electician.
If you haven't been able to install a fused spur in the vicinity of your window, you can still attach a plug top to the end of the cable, meaning that the blind can be plugged into and powered from a near by 3-pin plug socket.
In either scenario, it is important that the fused spur or plug top are fitted with the correct size fuse for the motor.
All appliances have what is known as a rated current which is the current that the appliance is designed to carry and use without it resulting in overheating or mechanical damage. According to electricalsafetyfirst.org.uk, “as a rule of thumb, fuses are rated according to the power rating of the appliance” and "appliances rated up to about 700 watts should have a 3-amp fuse"
The rated current in the motors used in our mains powered roller blinds is usually 0.5-0.6 Amp, and they have a power rating of between 90-130W.
So a 3 amp fuse will be sufficient to protect the cabling and motor.
If you are installing more than one mains powered radio operated roller blind, they cannot unfortunately use the same fused spur. Each motor should have its own switched fused spur. One of the key reasons for this is that during configuration of the blinds (and at a later date should you need to re-programme them), only the blind you are working with should be powered up, all other blinds should be switched off. If you don't have a switched spur per blind, then to power down the blind, you would need to disconnect it entirely from the spur.
The benefit of battery powered blinds is that no cabling is required, making them ideal for installation when you've not got mains power supplies or cabling installed to the windows. So under normal circumstances, there will not be a cable from the blind to mains power. However, of course, battery powered motors contain rechargeable (normally lithium ion) batteries which will need to be periodicaly charged. For this, you can purchase a charger which will be pre-fused and plug into a standard 3-pin plug socket.