FCU 's in Ring Main - advice.

[chrisgc]

Just some advice needed with regards to a few items permanently connected in a kitchen circuit.

Ring main circuit in a kitchen so will include a few double sockets, plus the following:

Extractor hood, Washing machine, Tumble dryer and Dishwasher.

Whats the best way to have the above items connected into the ring?

Is it FCU for each item then each FCU leading to Single socket for each of the items?

Also can an FCU be connected directly in the ring ie, between sockets OR is it preferred to have the spurring off a socket in on the ring?

PS. Its a new circuit so not adding onto an existing.

 

[telectrix]

FCU for extractor, fused down to 3A or 5A. for the washer etc, i would use 20A D/P switches, maintaining the ring final circuit through each switch, with a single 2.5mm drop to single socket for each appliance.

 

[Lucas123]

grid switch with individual fuse carriers to differentiate between appliances according to its load

 

[telectrix]

no need for fuses in grid switches. the appliances are fused at the plug tops.

 

[malcolmsanford]

The grid switches is indeed as the lads say a better way to go.

But you can indeed incorporate FCU into your ring final as per the regs, because it is a BS 1363 accessory.

 

[chrisgc]

The appliances are not next to each other so differentiating between each item may not be needed. For instance appliance then cupboard then appliance etc.

If anyone could do just a quick sketch as to the easiest and cost efficient method I would appreciate it.

 

[Lucas123]

Tel
i have had this arguement over and over again i am with you the fuse in the plug top is protecting but the mob im testing for at the minute have the grid switch in place with the double module (that being the fuse carrier)

 

[Guitarist]

Appendix 15 in the BGB will give you some ideas.
I'm with tel regarding sockets for your appliances.

 

[brman]

if you fuse it you don't have to stick to the 1 spur per socket rule I guess.
Could be an issue at a house I was at recently where each room had one socket on the ring and a second socket as a spur. So no adding of unfused spurs in that house......

Out of interest, why the recommendation for the grid switch instead of an FCU? Is it to get DP isolation?

 

[telectrix]

you can also get D/P FCUs.i prefer D/P isolation, whichever way it's achieved as , in the case of an appliance earth fault, it can be isolated without dragging the machine out.

 

[telectrix]

Tel
i have had this arguement over and over again i am with you the fuse in the plug top is protecting but the mob im testing for at the minute have the grid switch in place with the double module (that being the fuse carrier)

tell the numpties to look up " discrimination" ( but not in nelson mandela's autobiography)

 

[Guitarist]

you can also get D/P FCUs.i prefer D/P isolation, whichever way it's achieved as , in the case of an appliance earth fault, it can be isolated without dragging the machine out.

I think most decent FCU's are DP as standard now mate.

 

[Amp David]

Only time you'd ever need to have a fuse in the grid setup is if the appliance for whatever reason was connected via a flex outlet.

 

[malcolmsanford]

So scenario of direct fitted appliances via wall plate, DP 20amp switches on wired say on a Ring final 32amp MCB.

if each appliance is less than 3 metres from the switch which is likely in a kitchen unless it is big , why are we advocating any other protection besides the main MCB, unless of course manufacturers instructions here

 

[telectrix]

13A BS1362 to protect the appliance cable, which is generally 1.5mm.

 

[chrisgc]

Just wondered then if this is ok?

 

[Octopus]

What you should consider is the visual impact of having so many sockets & FCU's on "show".

I tend to use the 2G + 1G metal boxes, where possible so that FCU's are directly adjacent to a socket so will not look to "busy". In such set ups the FCU and the socket are still on the ring.

 

[chrisgc]

What you should consider is the visual impact of having so many sockets & FCU's on "show".

I tend to use the 2G + 1G metal boxes, where possible so that FCU's are directly adjacent to a socket so will not look to "busy". In such set ups the FCU and the socket are still on the ring.

The sockets will be behind or to the side of appliance so out of view but obviously the FCU's or DP switchs will be visible so as to be accessable.

Just trying to get some ideas but I do know what you mean about considering the visual impact especially as its a kitchen with granite work tops and back drops etc.

Any solutions please fellows??

 

[Guitarist]

Just wondered then if this is ok?

Nothing wrong with that mate.

 

[chrisgc]

Nothing wrong with that mate.

Thanks for that, I know its a bit basic and visually not the best but dont really know much about those grid switches.

Thinking visually it would be nicer to have the washing machine, tumble dryer and dishwasher on a 3 gang switch plate to cut down on the DP switches.

How are these grid switch plates wired in regards to my diagram???

 

[Octopus]

The sockets will be behind or to the side of appliance so out of view but obviously the FCU's or DP switchs will be visible so as to be accessable.

Just trying to get some ideas but I do know what you mean about considering the visual impact especially as its a kitchen with granite work tops and back drops etc.

Any solutions please fellows??

What I meant was if you have a 2G socket above the worktop, use the 2G + 1G box so that the FCU or double pole switch is immediately next to the existing socket. I wasn't meaning have the FCU and the socket for the applicance above the worktop!

 

[chrisgc]

Thinking visually it would be nicer to have the washing machine, tumble dryer and dishwasher on a 3 gang switch plate to cut down on the DP switches.

How are these grid switch plates wired in regards to my diagram???

 

[shocking_eg]

dont forget to think about loadings.

had a call out the other day, home owner was tripping her 32A mcb, tumble fridge, washing machine and kettle where on together ! lol

i would use the grid for the appliances and run a seperate 2.5mm ring for the grid switch / appliance circuits.

 

[Guitarist]

Tbh, many houses are wired on one RFC and never have any problems. I think you need to educate her on spreading her chores...

 

[shocking_eg]

Tbh, many houses are wired on one RFC and never have any problems. I think you need to educate her on spreading her chores...

haha tell me about it !

usually diversity takes it course - not in this case !!

 

[chrisgc]

So am I taking it that grid switches is not the way to go?

 

[shocking_eg]

So am I taking it that grid switches is not the way to go?

why not ?

its your choice, easier in my opinion - just chase in a deep box

 

[chrisgc]

why not ?

its your choice, easier in my opinion - just chase in a deep box

How are the grid switches wired in then in comparison to my original diagram as have not used these?

 

[shocking_eg]

just run power into the box where the grid switches will be mounted into, either off the ring main or by a dedicated circuit. then from the grid box run a 2.5mm radial to each of your three appliances.

and terminate the radials into each of the three 20A grid switches and link across your supply cable between the 3 switches.

just think of it as a 1 way light switch that the switch line / loop in is made within the switch itself.

simples really

 

[chrisgc]

Does the grid switches create a heavy load in one particular area?

 

[chrisgc]

Just want the least amount of fittings possible.

 

[gafc156]

I`m with you Tel i always install D/P gid switches with sockets either behind appliance or in the next available cupboard if intergrated

 

[WayneL]

I don't see the point of 'local' isolation, personally.

In my kitchen, it's 5 steps to the CU under the stairs........isolate it there.

If it's emergency switching you require - again, I don't see the point.

If there was an earth fault, it would be off anyway.

Is there actually a regulation that requires this.......or is it 'good practice' again??

 

[gafc156]

For me its neat and tidy, and you don`t get unsightly switched spurs everywhere. the only issue i have with isolation under the stairs is if you have somebody to come out and repair your appliance he/she needs to be able to isolate it before removing appliance. this should really be isolated in the same room he /she is working, and not in another room not under there control.

 

[WayneL]

For me its neat and tidy, and you don`t get unsightly switched spurs everywhere. the only issue i have with isolation under the stairs is if you have somebody to come out and repair your appliance he/she needs to be able to isolate it before removing appliance. this should really be isolated in the same room he /she is working, and not in another room not under there control.

Why, though?

If I go out to work on a dodgy socket in the living room, I isolate under the stairs......what's the difference?

And who said anything about 'unsightly' switched spurs.

Without the need for local isolation, you can either run the ring through the 'behind cabinet' sockets, or spur down off the worktop sockets........no 'unsightly' switches at all.

I'm just curious as to a specific 'regs' number that makes people think this is necessary....anyone??

 

[gafc156]

I see your point, and i sort of agree, however you are talking about an electrician isolating a circuit which we all do. however i don`t think a non electrician should be turning off an mcb at the ccu to work on a faulty appliance. i dont think it makes sense surely it is better to isolate one circuit and not the whole kitchen or in some cases the whole flat.

 

[Geoffsd]

Local isolation is more useful in the case of a faulty appliance which may be tripping the RCD - until the repairer arrives.

When he does he will unplug it.

 

[WayneL]

I understand the convenience etc etc - I just wondered if there was an actual regulation requiring this, or it's up to the individual?

I'm mainly asking because a recent job I looked at had six double socket outlets spread around the worktops - in addition to this there were five SFCUs - feeding under counter sockets/equipment, a cooker isolator and a fan isolator.......to be honest, it looked a mess.

 

[Des 56]

I agree with Waynel sentiments

I dont think there is anything specific about switches for isolation of an individual appliance,after all if the machine is broke,it can be pulled out and unplugged

I tend to just go with what the customer feels about switching,whether its a grid,double pole isolators or the dreaded "Put them in a cupboard"


I must say,the under the stairs option is one I haven't tried,but I think I would give that one a miss, although it probably covers any regulation requirement
In a TT with double pole isolation,we dont always double pole everything,but sometimes rely on the main switch to cover that issue

 

[Guitarist]

Basically, it's a convenience and safety factor. My parents are always turning everything off after they have used it, including the dishwasher and washing machine. If it's switched off (unplugged), it's safer than left on. Can't fault their logic, so they have switches above the worktop in line with the appliance socket underneath.
Regarding this "looks" issue.... there are loads of very nice looking switches and sockets and a kitchen is after all supposed to be a working environment, not a work of art!