2 cut-out fuses

[JohnW2]

If the second fuse were feeding a second CU in the same house, would you call it a looped supply? ... I'll assume you answer no.

You assume correctly.

If the second fuse were feeding a second CU in a different house, would you call it a looped supply? ... From your comments so far I'll assume you answer yes but I don't see a difference.

Well it's not so much "my answer" as the issue that we';ve been discussing. In an attempt to get us closer to understanding each other, allow me to ask you a slight variant of your questions, namely ..

"If the second fuse holder contained a solid link, rather than a fuse, and were feeding a second CU in a different house via a DNO fuse (and a meter) in that second house, would you call it a looped supply?"

If your answer is 'yes' then it seems that, as I suggested, your distinction is purely on the basis of whether the fuse for the second house's supply is in the first house or the second house - is that your belief?

As a slight aside (and a further aid to clarification), do I take it that you would regard what I have here (well, my neighbour) as being a "looped supply"? Because the supply is overhead, there is no 'cutout' in the conventional sense, just three fuse carriers (and a small 'Henley' for the neutral). The two arrowed cables (from DNO side of the fuses) goes to 'the house next door' (which was once a part of what is now my house), where there is presumably a DNO fuse (and meter). Do you call that a "looped supply"? [note that the photo was taken before a meter-changer-man covered the exposed (red!) insulation of the incoming neutral with grey silicone ]...

Kind Regards, John

 

[JohnW2]

All OP needs to know at this stage is there is a 1ph supply and to establish the earthing arrangement.

Indeed. Although there is no PME sticker to be seen, the earth appears to be coming pfrom somewhere close to the outgoing neutral, so it seems quite likely that it is TN-C-S, doesn't it?

Kind Regards, John

 

[SUNRAY]

You assume correctly.
Well it's not so much "my answer" as the issue that we';ve been discussing. In an attempt to get us closer to understanding each other, allow me to ask you a slight variant of your questions, namely ..

"If the second fuse holder contained a solid link, rather than a fuse, and were feeding a second CU in a different house via a DNO fuse (and a meter) in that second house, would you call it a looped supply?"

If your answer is 'yes' then it seems that, as I suggested, your distinction is purely on the basis of whether the fuse for the second house's supply is in the first house or the second house - is that your belief?

At this point I'll declare grey area. It's not a situation I've come across but I dare say it exists. Essentially it's not 'looped' anywhere, [just taken from an output], especially as it's so easily disconnected at that point.

As a slight aside (and a further aid to clarification), do I take it that you would regard what I have here (well, my neighbour) as being a "looped supply"? Because the supply is overhead, there is no 'cutout' in the conventional sense, just three fuse carriers (and a small 'Henley' for the neutral). The two arrowed cables (from DNO side of the fuses) goes to 'the house next door' (which was once a part of what is now my house), where there is presumably a DNO fuse (and meter). Do you call that a "looped supply"? [note that the photo was taken before a meter-changer-man covered the exposed (red!) insulation of the incoming neutral with grey silicone ]...

View attachment 208204

Kind Regards, John

If the feed to next door is directly off the incoming feed with no intermediate fuse or means of isolation then absolutely looped supply. I assume the brown wires come directly from the overhead lines and then direcly to the neighbour.

If I'm honest I'm not keen on the term 'looped' but I can't think of a more appropriate term.

 

[SUNRAY]

I think the first 3 sketches are fairly straightforward.

4th is so close to 3rd that I'd not use the term 'looped', however if 'looped' is the acceptable term for a service supplied this way then so be it.

Apologies for the large format, I tried to shrink it but it pixilated.

 

[JohnW2]

.... "If the second fuse holder contained a solid link, rather than a fuse, and were feeding a second CU in a different house via a DNO fuse (and a meter) in that second house, would you call it a looped supply?" ... If your answer is 'yes' then it seems that, as I suggested, your distinction is purely on the basis of whether the fuse for the second house's supply is in the first house or the second house - is that your belief?

At this point I'll declare grey area.

It's starting to seem that it's all 'grey' ....

[re my question above] It's not a situation I've come across but I dare say it exists. Essentially it's not 'looped' anywhere, [just taken from an output], especially as it's so easily disconnected at that point.
[re my own installation, as illustrated and described] If the feed to next door is directly off the incoming feed with no intermediate fuse or means of isolation then absolutely looped supply.

... so, it seems that you feel the first case is "not looped anywhere" whereas the latter is "absolutely looped". However, the only difference between the two is that the L feed to 'next door' connects to the DNO's incoming L at the incoming side of the DNO's fuse in the latter case and connects to the DNO's incoming L through a 'solid connection' in a fuse holder in the former case. Is that really enough to make a difference between "looped" and "not looped"?

If I'm honest I'm not keen on the term 'looped' but I can't think of a more appropriate term.

"Looped" does seem to be a less-than-helpful term - would we not usually call a situation like this "daisy-chained", or something like that? The reality is that the only significance of such an arrangement is in relation to the CSA of the DNO's incoming conductors. With both 'conventional' and 'looped' supplies, the supply to the cutouts in the two premises in question come straight from the 'main' ('in the road', or wherever), so the only functional difference is whether the cable ('from the main') has an adequate CSA to service two, rather than one, installation(s).

Kind Regards, John

 

[JohnW2]

Apologies for the large format, I tried to shrink it but it pixilated.

Reposted here in more manageable size. Comments will follow shortly ..

Kind Regards, John

 

[SUNRAY]

It's starting to seem that it's all 'grey' ....
... so, it seems that you feel the first case is "not looped anywhere" whereas the latter is "absolutely looped". However, the only difference between the two is that the L feed to 'next door' connects to the DNO's incoming L at the incoming side of the DNO's fuse in the latter case and connects to the DNO's incoming L through a 'solid connection' in a fuse holder in the former case. Is that really enough to make a difference between "looped" and "not looped"?
"Looped" does seem to be a less-than-helpful term - would we not usually call a situation like this "daisy-chained", or something like that? The reality is that the only significance of such an arrangement is in relation to the CSA of the DNO's incoming conductors. With both 'conventional' and 'looped' supplies, the supply to the cutouts in the two premises in question come straight from the 'main' ('in the road', or wherever), so the only functional difference is whether the cable ('from the main') has an adequate CSA to service two, rather than one, installation(s).

Kind Regards, John

Personally I feel the existance of the solid link does make the distinction as it is easily removeable.
Daisy chain implies to me that one thing leads on to another, a series of 10m extention leads daisy chained to reach 100m would be an example. As it happens in my mind 'daisy chain' describes your red example, however as i mentioned before I'd happily conform if others think 'looped' is the appropriate term.

 

[b21playa]

So mine looks like the 2 supplies diagram with one 1 being used. I guess at some point way before I purchased the house there could of been 2 meters

Originally I think the house was a 3-bed and then an additional room was put over the garage and then the loft conversion with 2 beds

 

[SUNRAY]

So mine looks like the 2 supplies diagram with one 1 being used. I guess at some point way before I purchased the house there could of been 2 meters

Originally I think the house was a 3-bed and then an additional room was put over the garage and then the loft conversion with 2 beds

That is a very possible scenario but there are other plausible scenarios too.

 

[JohnW2]

I think the first 3 sketches are fairly straightforward.

I and 2 are certainly very straightforward, representing the two common situations.

#3 is also straightforward but (at least in my experience) very uncommon - but, as I've been saying from early on (and as the OP now seems to agree), seems to be the most likely historical explanation for the OP's second fuse holder (the feed from it to 'somewhere else' having since disappeared).

As I've said before, your #3 ("Two Services") only really differs from #2 ("Looped") as regards whether the fuse for 'House 2' is in 'House 1' or 'House 2' - which is why I think many people would probably also call #3 "looped"..

I suppose we should remember that, although it doesn't look like a "4-pole" cutout, we're not absolutely certain that the two fuse holders are connected to the same phase.

4th is so close to 3rd that I'd not use the term 'looped', however if 'looped' is the acceptable term for a service supplied this way then so be it.

I'm not totally sure what you were trying to illustrate here. If it is meant to represent the situation of my hypothetical scenario (with solid link in the neutral fuse holder), it's not very clear, since it is not apparent from your diagram that (unlike all the other 'red rectangles') the left hand of the two red rectangles in the "DNO cutout" is a solid link, rather than a fuse. I was not suggesting that such was something one would be likely to see in practice, but was illustrating how close it was to other arrangements.

Kind Regards, John

 

[JohnW2]

Personally I feel the existance of the solid link does make the distinction as it is easily removeable.

I would have thought that "looped" was an attempt to describe the topology of the wiring, rather than precise details of connectiuons in that wiring, or how easily parts of it could be "removed".

As for "removablity", I don't think there is all that much difference. In both cases, one would have to break the seal of the fuse holder, open it and pull the fuse holder (bearing either a fuse or a 'solid link'). The only 'less easy' thing about my house (as compared with the hypothetical example with a link) would be that one would have to loosen one screw and withdraw the 'loop' conductor (which a DNO man would probably do 'live').

Daisy chain implies to me that one thing leads on to another, a series of 10m extention leads daisy chained to reach 100m would be an example.

As above, I think what we really are (or should be) talking/thinking about is the topology of the wiring, and the important thing about a 'looped' (or 'daisy-chained') supply is that it goes first to one house, and then on to another, such that the cable feeding the first house has to carry the combined current load of both houses. That's exactly the same as if one 'daisy-chained' a number of multi-outlet extension leads - again, the cable of the first extension lead would have to carry the combined current of everything.

As it happens in my mind 'daisy chain' describes your red example, however as i mentioned before I'd happily conform if others think 'looped' is the appropriate term.

Well, I'm certainly no authority, and I was hoping that you would be telling me what was the 'appropriate term' in the various scenarios! We both know what a 'looped' supply usually (nearly always) means and it's only in the unusual situations we've discussed that we are not sure. As I've implied, to my mind the most crucial thing is whether the cable to House 1 has to carry the combined currents of both House 1 and House 2.

Kind Regards, John

 

[b21playa]

It would be interesting to see actual cables. Maybe when I get DNO out on completion to upgrade my supply I can ask them

 

[JohnW2]

It would be interesting to see actual cables. Maybe when I get DNO out on completion to upgrade my supply I can ask them

Which cables would you be interested in seeing?

Kind Regards, John

 

[SUNRAY]

#3 is also straightforward but (at least in my experience) very uncommon - but, as I've been saying from early on (and as the OP now seems to agree), seems to be the most likely historical explanation for the OP's second fuse holder (the feed from it to 'somewhere else' having since disappeared).

In my experience 'Two Services' is extrememly common, in 70's it was very common to build terraces/semi's with a shed adjacent to the front door which contained the services, the gas, water and electric supplies often came up in one and then teed to the neighbour with the leccy coming from a second fuse in the head. Multi occupancy buildings [conversions] often have several whole installations in one space with only one head[RF Lighting has posted several pictures]. I assisted with a fusebox change very recently which has a 3ph supply and Henley blocks before the meters feeding 7 flats. I see no reason to call this 'looped'

As I've said before, your #3 ("Two Services") only really differs from #2 ("Looped") as regards whether the fuse for 'House 2' is in 'House 1' or 'House 2' - which is why I think many people would probably also call #3 "looped"..

Ultimately all the power comes from the same place so we could class everything as looped despite the fact that the vast majority is fed like a backbone.

I suppose we should remember that, although it doesn't look like a "4-pole" cutout, we're not absolutely certain that the two fuse holders are connected to the same phase.

Quite so

I'm not totally sure what you were trying to illustrate here. If it is meant to represent the situation of my hypothetical scenario (with solid link in the neutral fuse holder), it's not very clear, since it is not apparent from your diagram that (unlike all the other 'red rectangles') the left hand of the two red rectangles in the "DNO cutout" is a solid link, rather than a fuse. I was not suggesting that such was something one would be likely to see in practice, but was illustrating how close it was to other arrangements.

Kind Regards, John

I don't believe it makes any difference if it's a link or fuse, the format would be identical.

I would have thought that "looped" was an attempt to describe the topology of the wiring, rather than precise details of connectiuons in that wiring, or how easily parts of it could be "removed".

As for "removablity", I don't think there is all that much difference. In both cases, one would have to break the seal of the fuse holder, open it and pull the fuse holder (bearing either a fuse or a 'solid link'). The only 'less easy' thing about my house (as compared with the hypothetical example with a link) would be that one would have to loosen one screw and withdraw the 'loop' conductor (which a DNO man would probably do 'live').
As above, I think what we really are (or should be) talking/thinking about is the topology of the wiring, and the important thing about a 'looped' (or 'daisy-chained') supply is that it goes first to one house, and then on to another, such that the cable feeding the first house has to carry the combined current load of both houses. That's exactly the same as if one 'daisy-chained' a number of multi-outlet extension leads - again, the cable of the first extension lead would have to carry the combined current of everything.
Well, I'm certainly no authority, and I was hoping that you would be telling me what was the 'appropriate term' in the various scenarios! We both know what a 'looped' supply usually (nearly always) means and it's only in the unusual situations we've discussed that we are not sure. As I've implied, to my mind the most crucial thing is whether the cable to House 1 has to carry the combined currents of both House 1 and House 2.

Kind Regards, John

I'm sure the DNO have that covered. My own home is looped, not at all sure where to, but I have been able to measure the different temperature of both. Classically and comically during the scenario everyone always choses to demonstrate/argue diversity, Christmas morning while cooking dinner. One was a few degrees above ambient but the other was was well over 30'C.

 

[SUNRAY]

This: https://www.diynot.com/diy/media/untitled.15083/ was a 1ph head with 2 fuses.