What to do with my Frankenstein fuse box?

[groovybug]

Hi everyone,

I’m just starting to make sense of the electrical system in my new place. The flat is 1900 and it has been upgraded bits by bits over the years. While most of the cables seems to be okay (PVC insulated, with a mixture of old red/black wires and blue/blown wires), the fuse box is a huge mess.

Please see the photos (ignore the pilxated bits, those are my neigbhour’s).
From what I can make out of, the main power supply goes through the meter then into an AEI splitter (?) (what is the right word for this). From the AEI there are 3 pairs of cables going into 3 different fuse switches/consumer units. First one is a REVO fuse switch, there are two cables coming out of this, so probably one ring main, controlling the majority of the sockets. Second one is a Wylex consumer unit, probably a more recent addition. There are two 32A MCBs, one for the oven, and the other for the boiler. Third one is a 15A Memette (switchgear?, why do we need this one?). This one strangely goes into another MEM fuse switch located on an upperfloor. This MEM fuse switch splits to 2 5A radial circuit running on the loft, one supplies lighting for living room, bedrooms and the other for kitchen and bathroom.

Questions,

1. Is there any huge problem you can see with the current set up that needs immediate attention?

2. I want to replace all these 3,4 (REVO, Wylex, Memette and MEM) units with a single modern consumer unit. Anything to watch out for?

3. Ideally, I would not want to rewire what has been there (they look ok), but just adding a few more circuits. How many circuits do you consider as minimum in a property (3 bed flat, 90m2)? I’m thinking just splitting the ring main into 3 separate ones, one for living room/bedroom/hallway, one for kitchen ground sockets (so fridge, washing machine, dishwasher) and one for kitchen counter sockets (kettle, microwave etc). (there is a seperate circuit for oven already)

Many thanks!

 

[flameport]

Everything in the photos is scrap, and should have been replaced decades ago. The Memette is 1950s, the Revo might be 1960s, the others perhaps 1980s.
The item with ??? is a power supply, probably for a door entry system.

It may be possible to retain the cables, but it depends on what type they are, their condition, where/how they are installed and whether there are enough of them - older properties typically had very few socket outlets, and if it gets to having to install a substantial amount of new cabling for new outlets it's likely to be easier and cheaper to do all of it in new.

Unless you intend wiring it in the style of the 1940s, rings are neither necessary or desirable.

 

[ericmark]

Mothers house, my old house, and this house all had the Wylex fuse box with the fuses replaced with MCB's until a few years ago.

Mothers house was a mixture of 1954 wiring to few years before my fathers death, and there was a problem installing a RCD, and it clearly needed a part re-wire to replace all the rubber insulated cables and cables which had been overloaded it was found 2.5 mm² had been used and the original 7/0.029 the latter seems OK but signs of melting on the 2.5 mm² where dad had fitted spur off spur through the live of the house. So only wiring done after 2004 was retained.

My old house also found some problems, but did not need a rewire, I had fitted RCD protection in around 1992 so any problems since then would have tripped the RCD as the problem arose, but mothers house there were so many faults, as said gave up and a re-wire was done.

This house after loosing two freezers full of food before moving the fuse box and consumer unit replaced with an all RCBO consumer unit so one circuit would not take out another one. I was lucky only 2 circuits with a problem, borrowed neutral, but when a RCD/RCBO is added it can find faults you didn't know existed, so before it is done need to do an EICR to find faults first.

And this is your problem, fitting a RCD will protect you better, and a SPD will likely protect your equipment better, but there could be loads of unknown at moment faults, which will raise their head when the fuse box is replaced with a consumer unit (CU).

A RCD or RCBO (RCD and MCB combined) measures the current in and out and if the same assumes non is going to earth, and when a fault develops it should trip before you get a shock.

A SPD looks for spikes on the supply, years ago a typical appliance like a radio transformed the voltage down before turning it to DC and the transformer would stop most of the voltage spikes, but new stuff uses switch mode supplies so mains voltage is connected direct to semi-conductors, so the chance of a spike causing damage is increased, by how much is debatable.

There are very few cases where we can say for certain a RCD or SPD would have saved people or equipment, but with a RCD likely Emma Shaw would still be alive today, although it was not the lack of RCD blamed for her death.

Until around 1990 I had not seem many RCD's or as they were called then ELCB-v, then RCCB. But we had to be very careful to ensure our homes were earthed, as water and gas went to plastic pipes many homes ended up without a good earth, my parents house being one.

We were suppose to get a PIR (periodic inspection report) latter called an EICR (electrical installation condition report) done on change of occupant or every 10 years which ever was the sooner, but in real terms this was rare, the home buyer report was likely the nearest we got, and for this house he pointed out a disused fuse box in the ceiling, which was in fact still in use.

It took me around 6 to 9 months before I got around to fitting a new modern CU, I was just careful until fitted, well still careful, but to add sockets, move lights etc, in the main can't be done until the CU is fitted.

BS 7671 is not retrospective, it does not force anyone to up-grade, but until upgraded you can't add anything. So it will need doing.

 

[333rocky333]

The AEI splitter, do not know why, but most people still call them a Double pole Henley block even though as in your case most nowadays are not made by Henley, they also make single pole versions.
Think the proper name nowadays is just a 100amp Single or Double pole connecter block.

 

[Colin Brenton]

I'd be seriously considering at least fairly significant rewiring, to be totally honest. If you've just bought, now is the best time to do it, rather than when you've decorated, had carpets put down etc.

That Memette unit looks to be 1930s/40s, to me, connected to rubber covered cabling and is long, long overdue for retirement.

Hate to be the bearer of band news, but if a job's worth doing, do it just once, and get it over with.

 

[Harry Bloomfield]

That Memette unit looks to be 1930s/40s, to me, connected to rubber covered cabling and is long, long overdue for retirement.

I agree on the age and the desperate need for at least that/those circuits to be rewired urgently. Probably, they supply the original lighting circuits, from when the place was first wired. I would expect it to contain a pair of porcelain wire fuse bridges, which contain asbestos, both live and neutral fused.

 

[plugwash]

Hi everyone,
1. Is there any huge problem you can see with the current set up that needs immediate attention?

It looks like an ancient setup that has had a bunch of peicemeal additions over the years.

The wiring is a tangled mess, which is difficult to make out and it can be hard to distinguish a grubby black from a dark grey in photos (much easier in person), but i'm pretty sure I see a mixture of old rubber and more-modern plastic in those pictures. Modern plastic has a very long life, but old rubber should have been replaced a long time ago. The general advice I've see with old rubber-insulated cables is to replace them as soon as possible, and not to touch them until you are ready to rip them out. Old rubber can harden and crack with age and this problem is greatly exacerbated by any movement of the cables.

As a rule of thumb, plastic twin and earth cables are generally white or grey, old rubber cables were more likely to be black. Braided insulation is strongly indicative of old rubber.

One thing I would be tempted to do is start turning things off one at a time, and trying to figure out what if-anything is actually supplied from each fusebox. I'm not 100% sure, but I think the oldest "memette" box may already be turned off (I wouldn't expect a handle to be sticking out like that in normal operating configuration), suggesting it may be redundant.

2. I want to replace all these 3,4 (REVO, Wylex, Memette and MEM) units with a single modern consumer unit. Anything to watch out for?

I think you will struggle to find an electrician who is prepared to connect a new consumer unit to old rubber cables. Certainly the electrical safety council advise against doing it. So the question becomes do any of the old rubber cables form a critical part of the installation?

And you also have the problem that the cables may well not reach a suitable location for the new consumer unit without being extended, indeed one of the consumer units you have pictured seems to be in a totally seperate location from the others.

3. Ideally, I would not want to rewire what has been there (they look ok), but just adding a few more circuits. How many circuits do you consider as minimum in a property (3 bed flat, 90m2)? I’m thinking just splitting the ring main into 3 separate ones, one for living room/bedroom/hallway, one for kitchen ground sockets (so fridge, washing machine, dishwasher) and one for kitchen counter sockets (kettle, microwave etc). (there is a seperate circuit for oven already)

Three rings seems over the top to me for such a property, one for the kitchen and one for the rest of the property is more than adequate. Even one for the whole property may be ok, but depending on the location of the kitchen it can lead to a concentration of load near one end of the ring which is not ideal.

 

[Harry Bloomfield]

I'm not 100% sure, but I think the oldest "memette" box may already be turned off (I wouldn't expect a handle to be sticking out like that in normal operating configuration), suggesting it may be redundant.

Sticking out/up is on for those old fuseboxes, hanging straight down is off. In the on position, the lid is interlocked so it cannot be opened until turned to off, in order to access the fuses.

 

[SUNRAY]

I'd be seriously considering at least fairly significant rewiring, to be totally honest. If you've just bought, now is the best time to do it, rather than when you've decorated, had carpets put down etc.

That Memette unit looks to be 1930s/40s, to me, connected to rubber covered cabling and is long, long overdue for retirement.

Hate to be the bearer of band news, but if a job's worth doing, do it just once, and get it over with.

As a nipper I remember 'helping' Dad fit a cast iron box of that style in the house we moved into in 1961.

 

[mattylad]

I had the memette type box as a power switch on my workbench once, although all protected elsewhere I thought it looked cool...
I was young then... lol

 

[JohnW2]

Unless you intend wiring it in the style of the 1940s, rings are neither necessary or desirable.

Whilst I am no champion of ring finals (but also not a fan of 20A radials), for which I agree there is little ongoing need/justification, I think that it would be fair to say that they were the generally-accepted (and almost ubiquitous) arrangement for sockets circuits for a good few decades beyond the 1940s, weren't they?

I may be wrong, but I would suspect that, even today, and for whatever reason, ring finals may well still outnumber radials for newly-installed sockets circuits.

Kind Regards, John

 

[SUNRAY]

Whilst I am no champion of ring finals (but also not a fan of 20A radials), for which I agree there is little ongoing need/justification, I think that it would be fair to say that they were the generally-accepted (and almost ubiquitous) arrangement for sockets circuits for a good few decades beyond the 1940s, weren't they?

I may be wrong, but I would suspect that, even today, and for whatever reason, ring finals may well still outnumber radials for newly-installed sockets circuits.

Kind Regards, John

Absolutely correct, My experience of new builds within sizable developments is almost exclusively ring finals, even the multi switch panel in the kitchen has its own ring (that is assuming they don't forget to put the second leg in).

 

[crystal ball]

Absolutely correct, My experience of new builds within sizable developments is almost exclusively ring finals, even the multi switch panel in the kitchen has its own ring (that is assuming they don't forget to put the second leg in).

Yep, a school I do minor stuff for had a £5m refurb & extension recently, rings everywhere

 

[ericmark]

I seem to remember MK socket spec 3 x 4 mm² or 2 x 6 mm² but many sockets not easy to get 3 x 2.5 mm² so if you want 32 amp circuits with ability to have 3 cables into a socket, then no real option but ring finals.

I have wired a ring final with 6 mm² and 2.5 mm² drops to each socket in a large warehouse, but domestic not really an option, the physical limitations of the 13 amp socket means in the main the ring final is the best compromise.

However it really does not matter, if a home has 6 radials or 2 ring finals, except even the cheapest RCBO is around £15 so looking at £60 extra to have radials. Plus more likely to over load a circuit with radials and cause a RCBO to trip.

So real question is what do you ask an electrician to do? I had this problem with mothers house, it clearly needed a rewire, first firm I said all I wanted, cost around £6000 next firm what I could get away with as a minimum around half the cost, but could not compare as both quoted for different amounts of work.

I could only find two who could complete within the time scale, so really toss a coin.

So decide what you can get away with, if you want more, then you can if funds allow ask for more to be done, the if I wanted this, this and this done how much extra, but start at base figure.

Also decide if staying in house while re-wired or moving out, it costs to always leave things safe, so more expensive if you stay in the home, in my case could not trust mother not to touch things, so no real option care home while being re-wired. Same applies with children.

A RCBO can vary a lot in cost but £13.19 on one site, and 100 amp RCD is £39.33 and MCB £1.52 likely need around 6 circuits so all RCBO will cost less than twin RCD so not worth not having all RCBO's.

I stipulated all sockets to be on the ring final, so I could spur off any socket they fitted latter.

 

[plugwash]

What are the options for kitchen sockets? (assuming the cooker is either gas fired or powered from a seperate cooker circuit)

A 20A circuit can power one full-size appliance plus smalls. So no real opportunity to exploit diversity, and you would probably want 4 of them for a kitchen, one for the washing machine, one for the dishwasher, one for the tumble drier, and one for the countertop sockets.

A 32A circuit on the other hand can power two full-sized appliances plus smalls. That means we can exploit diversity, it's unlikely that more than two appliances will be at full load at the same time, so we can cover the whole kitchen with one circuit.

4mm² is borderline for 32A, it will pass with method C and no derating factors, but only just, almost any derating or adverse installation methods will push you up to 6mm² which is expensive and inconvenient. You can find sockets that are rated for 2x6mm² but I don't think I've ever seen one rated for 3x6mm², so a 6mm² radial would make any expansion a PITA.

With a ring though, you are allowed to install 20A cable on a 32A circuit. 2.5mm² has a much bigger margin for a 20A circuit than 4mm² does for a 32A circuit and if you do have to step up due to adverse installation conditions, you are only stepping up to 4mm² which still gives room in the terminals for a spur.