Gridswitch fuse spur?

[Mike Blair]

alright guys i have to get a 8 way grid switch but i have installed one. currently on a job where the electrician has left and i have taken over his job and has been a utter nightmare... there designer wants to use a 8 way grid switch 20amp double pole but someone was saying the fuses go in the back of the switch?!? never seen this i think hes confused! o_o

 

[Risteard]

You can get fuse modules and/or flex outlet modules depending what exactly is needed. Of course they will take up a module each though in addition to the switch module!

 

[Richard Burns]

You would have to specify your requirements more clearly.
Generally if you have a 20A DP switch then this is feeding a socket, for which the fuse will be in the plug so a fuse is not required at the switch.
If the 20A DP switch is not feeding a socket then is fusing down required, as the circuit should be protected at origin.
If you are switching four items then you can have both a switch and a fuse in the 8 gang grid.
I certainly would not recommend having fuses behind the switch plate as this is an inaccessible and inobvious nightmare.

 

[Mike Blair]

could someone show me a grid with fuses and switchs i have never seen one tbh o.o thats why im confused as hell. and no one else on site "designer" etc knows -.-

 

[Mike Blair]

instead of fuse spurs everywhere there using the grid switch so its all in one place

 

[Flanders]

could someone show me a grid with fuses and switchs i have never seen one tbh o.o thats why im confused as hell. and no one else on site "designer" etc knows -.-

here one https://www.bing.com/images/search?...407db4ebb74b6ed6af14650fc4825613o0&ajaxhist=0

 

[Mike Blair]

i see so i would probs have to get a 8way wago to split the feed into each fuse o.o haha

 

[telectrix]

no, you loop the feed from 1 module to the next, then the next, etc.

 

[Flanders]

No you feed to your fuse then from your fuse to the switch and then from the switch to the load. so in an 8way grid you could have 4 outgoing loads

 

[Richard Burns]

For an 8 gang switch you could arrange things like this to provide witching and fusing for four items.

and wire like this

 

[amlu]

click minigrid modules are nice
https://www.electricalcounter.co.uk...ur+Connection+Unit+Minigrid+Module/4021078815

 

[Flanders]

click minigrid modules are nice
https://www.electricalcounter.co.uk...ur+Connection+Unit+Minigrid+Module/4021078815

Yes I do like these but I don't think they do an 8 way face place that the OP requires

 

[123]

Yes I do like these but I don't think they do an 8 way face place that the OP requires

They do a 12 and 18 way though. By the sounds of it more than 8 ways will be needed as the fuses haven't been allowed for.

 

[Risteard]

Personally I would feed the switch modules first and then the fuses. It means you aren't inserting or withdrawing a fuse into an energised carrier then if the switch is open.

 

[ipf]

Personally I would feed the switch modules first and then the fuses. It means you aren't inserting or withdrawing a fuse into an energised carrier then if the switch is open.

...open?

 

[Risteard]

...open?

If the switch is open the carrier will be de-energised. If the switch is closed it will be energised.

 

[ipf]

If the switch is open the
Sorry...misread. Maybe 'because the switch is open' would have read easier :lipsrsealed2:

 

[TJ Anderson]

No you feed to your fuse then from your fuse to the switch and then from the switch to the load. so in an 8way grid you could have 4 outgoing loads

The fuse is put in series after the switch for the reasons Risteard has said. That's why switched fused spurs are constructed in same way.

 

[Richard Burns]

I would have to say the fuse after switch scenario is probably safest but I could not be bothered to change the diagram, FCU carriers are designed to be safe to insert fuses even when energised as they are for unskilled use but no sense in increasing risk.
wire like this in that case.

 

[Flanders]

The fuse is put in series after the switch for the reasons Risteard has said. That's why switched fused spurs are constructed in same way.

Yes i do agree with you . I did write my post that way first then edited it to read the otherway around after seeing richards drawing for continuity as i felt it does not make much difference , I agree with you that industrial switched fuses are wired this way otherwise you could touch a live part of the fuse even when tured off. but with the type of fuse holders we are talking about there is no way of touching the live part of the fuse when inserting it, saying all that going to the switch first is the better way of doing it

 

[Adam W]

I would have to say the fuse after switch scenario is probably safest but I could not be bothered to change the diagram, FCU carriers are designed to be safe to insert fuses even when energised as they are for unskilled use but no sense in increasing risk.
wire like this in that case.
View attachment 32430

At the risk of sounding pedantic you've drawn the supply as a radial, ie to be able to use a 32A OCPD you'd need to terminate 2 x 4mm² wires in each terminal, except in the last, and then you need to get all the wires in the backbox to screw back the faceplate.
I don't think you'd get very far wiring it in a 2.5mm² radial - you might be OK running a gas hob, extractor and possibly fridge freezer, but you might be in trouble if the compressor were to kick in while the washer dryer were running, especially if the customer had set it and gone out for the day expecting to come home to clean dry clothes but instead found a washer dryer full of clothes and water and a freezer full of food and water.

IMO it would be easier to wire this in a 2.5mm² ring to be able to draw the 32A.

 

[7029 dave]

At the risk of sounding pedantic you've drawn the supply as a radial, ie to be able to use a 32A OCPD you'd need to terminate 2 x 4mm² wires in each terminal, except in the last, and then you need to get all the wires in the backbox to screw back the faceplate.
I don't think you'd get very far wiring it in a 2.5mm² radial - you might be OK running a gas hob, extractor and possibly fridge freezer, but you might be in trouble if the compressor were to kick in while the washer dryer were running, especially if the customer had set it and gone out for the day expecting to come home to clean dry clothes but instead found a washer dryer full of clothes and water and a freezer full of food and water.

IMO it would be easier to wire this in a 2.5mm² ring to be able to draw the 32A.

Like an dedicated RFC just for the grid?. Yep like that design.

 

[Richard Burns]

I am only showing the looping of the supply for the switches, a 20A radial for an extractor hood and 3 sets of lights would be fine, since we do not know the loading or the use for the switches to say it must be a 2.5mm² 32A ring is failing to be pedantic!:wink_smile:

but just for you

however if it is a ring then you should be careful of grouping heavy loads on the ring (yeah right).

 

[Risteard]

...open?

Yes - the switch open as opposed to closed, i.e. the load side is de-energised.

 

[brianmoooore]

Yes - the switch open as opposed to closed, i.e. the load side is de-energised.

@Risteard You've replied to a thread that hasn't seen a post for close to a decade,or is the forum clock acting up again?

 

[Risteard]

@Risteard You've replied to a thread that hasn't seen a post for close to a decade,or is the forum clock acting up again?

I replied to a post quoting me. That post seems to have now disappeared. Not sure what is happening to be honest.