Very old henley fuse box

I cant comment on what it would or wouldnt cost to get the DNO in, and that might be the best first option but I cant imagine it would cost and arm and a leg to get a spark in for an hour to give it a look over and shed some light. Some might be able to do that job on there own, but where the other wires go, and where the feed for the flats comes to is potentally relivent.
All true, and the OP is apparently going to discuss all this with his mother. However, it would seem that he feels her inclination will be to 'let things be', doing without the intercom, in order to avoid the hassle and potential cost of opening up a potential can of worms. It's clearly not what we would advise, but it's ultimately her decision.
Although thought that comes to me is, is it possable that the locked box contains a meter? Seems unlikely but so does the shared lighting being unmetered.
Almost anything is possible!

Kind Regards, John
 
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The initial visit from the DNO will be free, and if they deem that cutout to be unsafe / unserviceable then it's their responsibility to replace it

I would aim to be there when the DNO guy came out, that way I could have a good chat with him get him to explain what's what to me.
 
The initial visit from the DNO will be free, and if they deem that cutout to be unsafe / unserviceable then it's their responsibility to replace it.
Yes, I realise that. I think the concern may relate to the possible consequences of what the DNO may have to say about what's currently connected to their cutout (and, indeed, what they are prepared {or not} to reconnect to a replaced cutout). Maybe westie might be able to comment on that.

There's obviously no doubt what course you, I and most others here would take - but we cannot necessarily speak for the OP's mother.

Kind Regards, John
 
the worst I can see the DNO doing is removing the supply to the intercom (no big deal as it's broken - may make things easier in the long run) and maybe the lights - that would be a greater loss.

If it was my flat, I'd want all the nasty old stuff ripping out and hell to the cost - which ofc is not the OP's mothers POV
 
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If it was my flat, I'd want all the nasty old stuff ripping out and hell to the cost - which ofc is not the OP's mothers POV
Hard isnt it, as clearly its not what would be designed or fitted today, but given it will have been fitted within her lifetime, although to a certain extent may be in a worse condition now than when it was fitted its never easy getting into a converstation about the fact that was was fine and good then now isnt.


Daniel
 
the worst I can see the DNO doing is removing the supply to the intercom (no big deal as it's broken - may make things easier in the long run) and maybe the lights - that would be a greater loss.
Is it just me? Apart from the fact that I'd obviously like to see that cutout replaced with something modern/safe, the main issue I see is those cables coming from it. Maybe it's an optical illusion, but they look very small to me, with no apparent protection other than the cutout fuses and, if they really are feeds to all the flats, are of goodness knows what (probably long) lengths and routes. ... all of which would make me wonder if the DNO would be happy/prepared to reconnect them to a replaced cutout - which is why I was hoping westie will be able to comment. Of course, I'm still not yet convinced that they necessarily are the feeds to the flats!

Kind Regards, John
 
Of course, I'm still not yet convinced that they necessarily are the feeds to the flats!
Which I guess is the main benifit of getting a spark in to have a look at it. As long as you dont get a spark who decides having seen it the only thing he can do it pull the plug no the lot and leave you with the lights off you have simply exchanged an hours wages for an hours infomation. If you can get someone in on personal recomendation, or a family freind, so much the better.

Daniel
 
As long as you dont get a spark who decides having seen it the only thing he can do it pull the plug no the lot and leave you with the lights off you have simply exchanged an hours wages for an hours infomation.
Indeed - but it sounds as if (whatever we may think) the OP's mother might prefer/choose not to receive that information.

Kind Regards, John.
 
Do those old Henleys contain asbestos?
That would seem quite likely. However, even without asbestos, I imagine that the DNO would probably want to change the cutout (presumably FOC). As I've been saying, it's their reaction to what is connected to the cutout which is probably what the OP (or his mother) is concerned about.

Kind Regards, John
 
Age wise it probably will be the same as the building, that style of cut-out I would date to pre 60's. 9which doesn't preclude pre-war.
It is likely with it's age that the supply was installed by a council and the Electricity Board and then the DNO has inherited it. Chances are there are too many to be easily changed unless it becomes a priority.

Looks like there is an individual fuse in each flat for local isolation, which could suggest the fuse size in the metal clad unit is higher than 100A, makes that small cable even less protected.

Oh, John W2 asked about the other cables and fuse sizes, as it seems likely that this is in the main DNO property I see no issue, we do not protect cables against overload. Fuses are to protect the system from faults and discriminate to reduce customer outages to a minimum.

With the fusing factor of the type of fuse we use in those units, a 100A fuse will carry 147A pretty much continuously. (from that you can work out what size we would need to protect a 100A rated cable from overload)
 
Oh, John W2 asked about the other cables and fuse sizes, as it seems likely that this is in the main DNO property I see no issue, we do not protect cables against overload. Fuses are to protect the system from faults and discriminate to reduce customer outages to a minimum.
I realise that, and it's really the basis of my question. One hears of DNOs complaining (or worse) about 'unprotected' meter tails a little more than 3m in length, but here we have seemingly undersized, 'unprotected' and quite possibly very long (and possibly inaccessible) set of 'tails' from the cutout.

...and we are perhaps losing track of something else, and thereby maybe assuming that 'those cables' are the consumer's property/problem. IF (as we have been told) the flats each contain a meter, and IF there are being supplied from that 3-phase head, then the cables I'm concerned about are those between the cutout and the meter. Are thin, 'unprotected' (other than by cutout fuse), potentially very long (and possibly inaccessible) cables acceptable for that purpose?

Kind Regards, John
 
One hears of DNOs complaining (or worse) about 'unprotected' meter tails a little more than 3m in length

The requirement is to operate the cut-out fuse within 5 sec for a fault on the tails or CU prior to the first point of the customer's protection (which is where the .8 Ze figure comes from, this may vary in some DNOs that install smaller fuses than the 100A we use.

Within modern installations, no this would not be acceptable. But this is a legacy set up some of which are extremely scary!
If we accept that there is a single phase cut-out in each flat the cables between that cut-out and the meter may be protected depending on the size of that cut-out fuse.
However I would agree that there would be an issue for a fault on the "sub-main" between the Henley unit & the flat. If they are in conduit all the way there is probably not a great risk so for a fault they could probably burn back until they became open circuit.

We did some flats in the 80's, consisting of ground, first floor and second floor. We fitted a 3 x 100A cutout on the ground floor feeding that flat and two concentric risers in steel conduit to the other two flats, The other two flats have single phase 100A cut-outs. All fuses are 1900A as all are accessible in viewing cabinets so we did not worry too much about discrimination. This is still the preferred for this type of housing.

Another variant sees a central meter position with a modern version of the Henley unit feeding a muli 100A fused unit feeding meters at that location. Individual fuse switches feed each flat
 
One hears of DNOs complaining (or worse) about 'unprotected' meter tails a little more than 3m in length
The requirement is to operate the cut-out fuse within 5 sec for a fault on the tails or CU prior to the first point of the customer's protection (which is where the .8 Ze figure comes from...
How does that equate to the oft-cited 3m limit? I would have thought that one could usually have a good few metres of 25mm² tails and still be able to meet that requirement.
Within modern installations, no this would not be acceptable. But this is a legacy set up some of which are extremely scary!
Fair enough.
If we accept that there is a single phase cut-out in each flat the cables between that cut-out and the meter may be protected depending on the size of that cut-out fuse. However I would agree that there would be an issue for a fault on the "sub-main" between the Henley unit & the flat.
Indeed - that's what I was talking about.

Kind Regards, John
 
How does that equate to the oft-cited 3m limit? I would have thought that one could usually have a good few metres of 25mm² tails and still be able to meet that requirement.

You tell me!
I've never been able to get to the bottom of how that particular length was decided, but it has been around for over 30 years.
In modern terms it should equate to the Ze of the supply and have a maximum.
 

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