Single FCU to Double FCU

[andybydna]

I have a single FCU (Fused Connection Unit?) in the garage that provides power for the garage door opener, it has a 13A fuse.

I want to add a smart garage controller to it that also requires power.

Can I convert the single FCU into a double FCU using two modular FCUs (https://www.screwfix.com/p/lap-13a-grid-fused-spur-white/29759) in the original box using a modular faceplate (https://www.screwfix.com/p/lap-13a-grid-fused-spur-white/29759)? They would have a 13A fuse for the door opener and 3A (or 1A) fuse for the controller.

I'm not yet sure if the existing FCU is a spur or not, as I've not been able to look yet.

 

[Sureitsoff?]

Or you could just put another standard fcu next to the existing one....

 

[andybydna]

Or you could just put another standard fcu next to the existing one....

Yeah I did consider that as one of my options, but it would be mounted to the fireproof ceiling (sorry I forgot to mention that) next to where the original is. I've no idea how easy/hard that is. I assume it's similar to plasterboard, but I have no idea what it is really.

These modular FCUs seemed slightly less hassle

My question was more in terms of electrical safety/regulations. But I guess a double FCU compared to one next to it is really no different? It also depends on whether the original is a spur or not?

If it's a spur, would I connect the second FCU to the fused side (output) of the first FCU, or to the other side (input)?
If it's not a spur would I just connect them both to the ring main, i.e. the same place?

 

[davelx]

Yes, if the original one is a spur you can just feed the new one from the downstream/output side. In fact even it it's not a spur.
I would not think you are likely to need the controller powered when there is no power to the opener.

 

[andybydna]

Yes, if the original one is a spur you can just feed the new one from the downstream/output side. In fact even it it's not a spur.
I would not think you are likely to need the controller powered when there is no power to the opener.

Ah OK that's cool, thank you

You're right about not needing power to the controller if the opener is dead lol .. in fact that might be better, as we get offline notifications from the controller, so that could indicate there's a problem with either.

 

[JohnW2]

I have a single FCU (Fused Connection Unit?) in the garage that provides power for the garage door opener, it has a 13A fuse. ... I want to add a smart garage controller to it that also requires power.
Can I convert the single FCU into a double FCU using two modular FCUs ...... They would have a 13A fuse for the door opener and 3A (or 1A) fuse for the controller.

You could, but does the controller really need the protection of a 3A fuse? If not, you could simply run it from the same (single) FCU supplying the door opener.

Kind Regards, John

 

[ericmark]

I used the LAP version the problem is there is no place for the neutral wires, not a problem with how I used it, as also had a socket, but the back box would need to be deep enough to take connectors for earth and neutral. The pair of LAP fuse holder would clip into the LAP 2-Module Modular Faceplate White (42092) but it is down to room remaining.

 

[andybydna]

You could, but does the controller really need the protection of a 3A fuse? If not, you could simply run it from the same (single) FCU supplying the door opener.

Kind Regards, John

Thanks John. This was also something I considered. But as the power cable to the controller is not very thick, I thought it best to have a lower rated fuse, just in case.

 

[andybydna]

I used the LAP version View attachment 344776 the problem is there is no place for the neutral wires, not a problem with how I used it, as also had a socket, but the back box would need to be deep enough to take connectors for earth and neutral. The pair of LAP fuse holder would clip into the LAP 2-Module Modular Faceplate White (42092) but it is down to room remaining.

Nice!

Luckily the existing back box for me is quite deep (plus it already had an earth connector built in), so I had plenty of room for a neutral connector.

I ended up opting for two LAP FCUs, as described in my original post.

It also turned out to be on the ring main, rather than a spur, which was a bonus (apart from the extra cables to deal with lol).

The controller is all working perfectly now, no more neighbours calling us to tell us the garage door has been left open hopefully!

 

[Harry Bloomfield]

Could you not, as they are both associated anyway, simply run both items off the one single spur?

Either both flexes into the one spur, or daisy chain them.

 

[JohnW2]

Could you not, as they are both associated anyway, simply run both items off the one single spur? ... Either both flexes into the one spur, or daisy chain them.

Already asked a while ago ...

You could, but does the controller really need the protection of a 3A fuse? If not, you could simply run it from the same (single) FCU supplying the door opener.

... but the OP has now responded ..

Thanks John. This was also something I considered. But as the power cable to the controller is not very thick, I thought it best to have a lower rated fuse, just in case.

... which, dependent upon the circumstances, could be a valid consideration.