Fused Spur

I recently added a Fibaro Smart Switch 2 to a heated towel rail fused spur, the way I opted to wire it up is so that the switch on the fused spur controls whether any electricity goes to the smart switch, so basically the switch will be left on (unless I want to turn it off completely, so it cannot be turned on even by SmartThings). I had to use this custom device handler https://github.com/GSzabados/SmartThingsPublic/blob/patch-5/devicetypes/fibargroup/fibaro-single-switch-2-zw5.src/fibaro-single-switch-2-zw5.groovy otherwise it didn’t see the status changes and was pretty useless (seems crazy this manual step is required, but I digress).

Now it is on SmartThings, I have automations set up to turn the towel rail on and off twice a day for morning showers and evening baths. One thing I thought would be great is if other members of the family who aren’t tech savvy were able to just switch the towel rail on for an hour if they want it warm at a time outside of this schedule. One option would be to have a smart button. But I wondered if anything exists which I could replace the fused spur with, which:

  • As per a normal fused spur, has a switch to turn on/off the appliance
  • Has a 1 hour ‘boost’ button, which can be hooked up to the switch circuit on the Smart Switch which would cause the appliance to turn on and then switch off an hour later.
  • Has a LED on the fused spur, but rather than being controlled by whether the switch is on or off, is controlled by current from elsewhere, i.e. I would like the LED to come on if there is power getting to the appliance (so after the Smart Switch has taken control). This way from looking at the fused spur you’d know whether the towel rail is actually on or not (rather than an LED which is always on, basically just saying power is being delivered to the Smart Switch).

Does anyone know if anything like this exists? Other than a smart button, I am thinking that maybe a smart panel (tablet?) mounted on the wall, with a couple of ‘tiles’ to do things like force the towel rail on for an hour could be a reasonable solution - but I am just trying to explore what currently exists - sometimes a simple old fashioned physical button and LED works out better…!

You have wired the spur and the smart switch in series, which means both have to be on for the rail to come on. If you wire them in parallel it would only need one or the other to be on for the rail to switch on. Thus you can have automation and the manual switch for other family members.

The things which put me off doing this:

  • There is not a way to isolate the radiator, i.e. the fused spur can be switched off yet, the Fibaro switching means power can still be getting to the radiator. I like the idea that it is possible to flick a physical switch and no that no power is getting there.
  • The fuse in the fused spur would no longer be protected, instead it would presumably just be down to the 30A fuse in the Fibaro which is very overpowered for the 5A fuse required for the towel rail.
  • It has my original problem, which is other family members switch the towel rail on and then forget about (and then say ‘it is only a few pennies to run per hour’ and forget that when they do that for heaters, towel rails, lights, clothes driers, etc. those ‘few pennies’ quickly become a ‘few hundred pounds’)!

I wonder if it would be overkill to replace the single fused spur with a double: one side being the fused spur (giving the ability to isolate, and meaning the fuse protects) but then also a switch next to it (connected up to the switch circuit on the smart switch). If I did that, I guess the last puzzle piece would be to set up some automation that notices when the device has been switched on outside of the time intervals I have set up and knows to then switch it off after an hour. I am guessing this would be possible somehow?

If you want the fibro circuit protected by a fuse then you’d have to use a fused spur but what are you protecting?? If you have a RCD (ELCB) or whatever they are called in your country they will protect persons, a fuse doesnt.

If you want to detect a switch left on you’d have to also put a smart device in that circuit to run that automation.

I was originally trying to give you a ‘free’ solution, but if your going to spend money and want to do other things. I would suggest a better solution would be to use something like a flic button as a local way to switch your fibro and just leave your circuit as is. You can then setup an automation to switch the fibro switch off after a certain time after the flic button has turned it on.

Hope this helps