Smart controller wiring

[gbrown100]

I have a bunch of smart controllers from Shelly designed to sit in the back of a socket backbox. Some have a rating of 8 amp, some 13. I wanted to use them to switch and monitor consumption of a bunch of 3D printers, one per socket. I have a 6KVA UPS being installed using a 16 amp radial input from the Consumer Unit and output as 16 amp radial also. My confusion lies over the rating of the smart controllers, neither are rated to 16/20 amp so would not be able to be connected directly to the in/out of the radial circuit as it passes through (i.e. as you would if just installing in a bunch of sockets). Also, since I guess they themselves are classed as devices shouldn't they have an isolating switch also?

I worry that there's no safe way to install these devices, what are your thoughts? Is jointing using Waygo's and feeding the controllers from those also safer and allowed?

Thanks

Graham

 

[jj4091]

Connect the 8A ones using FCU's and fuse them appropriately. The 13A ones will be OK in normal 13A sockets.You don't need Isolating switches for the devices.

 

[gbrown100]

Thanks @jj4091 . The concern is that even the 13 amp ones, the terminals don't seem man enough to cope with anything over 13 amps, if wired as part of a 20 amp radial could the terminals get too hot if they're being used to connect between the cable segments for the circuit and its running close to capacity?

I mean the devices plugged in shouldn't be drawing anywhere near that much unless something goes wrong but with 3d printers that's a distinct possibility!

 

[jj4091]

"I mean the devices plugged in shouldn't be drawing anywhere near that much unless something goes wrong but with 3d printers that's a distinct possibility!"
That seems a bit contradictory. I thought you were concerned about the curreent draw on the controllers not the circuit.
You should be able to get 2 x 4mm cables in the terminals of a socket or FCU without any problem.You need to check if 4mm is suitable for the instalation method. A 13a fuse in each plug on the printers will stop them drawing more than that from a socket and a smaller one in the FCUs will have the same effect. But you need to ascertain what the rating is for each device and connect it to the appropriate outlet.

 

[Murdochcat]

are you considering have a number of these on a radial circuit? If so I would agree that the terminals are highly unlikely to accommodate 2 x 2.5mm cables.

I would recommend putting these "downstream" of a DP isolating switch or S FCU

 

[jj4091]

I mis-understood how these devices worked. Yes, teeing off with wagos to each controller then using that to switch a suitably fused FCU for each device is probaly the way to go.

 

[ericmark]

How will you control them with a power outage? I have UPS to freezer and central heating, but with power outage can't use my phone to control the central heating as the router has no power.

Anything mechanical will at some time fail, so better if any smart device can be unplugged and replaced, just had an outside light fail due to the plug in smart adaptor, cure was easy, took the one controlling the fan, and using that until I get a replacement, all my UPS supplies are easy to by-pass UPS should the UPS fail.