Gridswitch fuse spur?

Risteard · Jun 9, 2016

ipf said:
...open?

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

ipf · Jun 9, 2016

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

TJ Anderson · Jun 12, 2016

Flanders said:
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 · Jun 12, 2016

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.

[ElectriciansForums.net] Gridswitch fuse spur?

Flanders · Jun 12, 2016

TJ Anderson said:
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 · Jun 12, 2016

Richard Burns said:
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 · Jun 12, 2016

Adam W said:
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 · Jun 13, 2016

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