Switches and sockets

[88v8]

I'd be more impressed if they could manufacture a dishwasher that would last longer than 5 years before it breaks down beyond economic repair.

Well, my wife has lasted more than five years

The switches... when last we had the system looked at for certification, the electrician was not bothered about the unscrewing issue with our ancient metal switches. A system cannot be 'failed' because it does not meet current, I mean present, standards.
But he did want me to devise a means of earthing them.

I have several more 60s light switches, the modern ones as I think of them, to replace with original jelly moulds, just haven't got round to it yet. One reason for the delay, as I realised the other day, is that the 60s switches are now beginning to look vaguely Period. This was a moment akin to seeing items from one's youth in a museum.

Ivor

 

[steveb]

if unscrewing covers is such an issue, could a solution be created with a small drill , a tap set and the insertion of a small grub screw underneath or other out of view location. If the screw head was painted brown or black it would basically disappear anyhow

 

[88v8]

if unscrewing covers is such an issue, could a solution be created with a small drill , a tap set and the insertion of a small grub screw underneath or other out of view location. If the screw head was painted brown or black it would basically disappear anyhow

Ingenious. I think the problem there would be that the brass covers are too thin to carry a thread, and the underpinnings are porcelain.

If one is really bothered - which I'm not - I suppose they could be Araldited on so that little fingers couldn't unscrew them. But it's handy being able to remove the covers for the annual Brasso.

Ivor

 

[Owain]

Cordless phones drive me mad enough when someone doesn't put it back in it's cradle and I can't find it (exactly why we have a 1960's wall mounted phone in the kitchen!)

Young people don't understand about not twisting the coily cord, though.

 

[Flyfisher]

The switches... when last we had the system looked at for certification, the electrician was not bothered about the unscrewing issue with our ancient metal switches. A system cannot be 'failed' because it does not meet current, I mean present, standards.

Correct, 'old' electrical installations cannot be failed simply because they don't meet the latest regs. Imagine the chaos if every new set of regs were retrospective (the same applies to anything really). But a 'competent person' won't be able to do any work, or certify it, that involves such 'out of date' parts. We had a fairly rudimentary electrical system, with quite a few rooms with no sockets and most other sockets on radial rather than ring circuits and all converging back to wired fuses, some in porcelein carriers.

All perfectly legal . . . until we wanted to add some new circuits, which meant a new consumer unit because the existing ones didn't meet current regs, though I didn't mind that because modern CUs are definitively safer than the old ones. But to minimise additional wiring and all the associated disruption I was happy to keep the radial circuits - perfectly safe (and compliant) as long as the main fuse is 16A instead of 30A - and let's be honest, outside of a kitchen or a utility room who actually needs 30A circuits these days?

We've also kept all the original non-compliant light switches except for one that we wanted converting for two-way switching, which involved new wiring and so could not be certified with the non-compliant switches.

But to be honest (heresy alert!!!!) I don't really 'get' this attachment to old, non-compliant and frankly dangerous switches and other electrical gizmos. It's not as if anything electrical is authentically 'period' (using the 100 year old definition for the term) in the first place. It's just 'old'. And often dangerous. Now candles for lighting, that's properly period but I'm guessing that nobody here is that keen on authenticity! :wink: :lol:

 

[Owain]

Now candles for lighting, that's properly period but I'm guessing that nobody here is that keen on authenticity! :wink: :lol:

Candles for me are authentic 1970s power cuts

 

[Feltwell]

Candles for me are authentic 1970s power cuts

Ahh yes, takes me back to my childhood, the waft of "pink paraffin" as you did homework by tilley lamp, dinner cooked on an ancient camping stove …...

Along with the Morris Marina, flares, casual racism on television and everything being brown, gold or orange. Some things really are best left in the 1970's!

 

[Me!]

takes me back to my childhood, the waft of "pink paraffin" as you did homework by tilley lamp

Oooo, you were posh. My dad used to drain a bit of oil out of the central heating tank to run oil lamps. They did smoke a bit

 

[Feltwell]

We had a gas lamp on a pole that screwed onto a calor gas cylinder as well. Very upmarket! :lol:

Mind you, whilst some of our power cuts were down to the strikes, more were down to the cows in the field next door pushing the wooden power posts over - used to happen quite regularly until the Electricity board finally buried the cable!

 

[88v8]

It's not as if anything electrical is authentically 'period' (using the 100 year old definition for the term) in the first place.

My definition of Period is anything older than me, which nowadays gives a lot of scope

Ivor

 

[Owain]

My definition of Period is anything older than me, which nowadays gives a lot of scope

No more or less scope than at any time since your birth, if you think about it.

 

[a twig]

All perfectly legal . . . until we wanted to add some new circuits, which meant a new consumer unit because the existing ones didn't meet current regs, though I didn't mind that because modern CUs are definitively safer than the old ones. But to minimise additional wiring and all the associated disruption I was happy to keep the radial circuits - perfectly safe (and compliant) as long as the main fuse is 16A instead of 30A - and let's be honest, outside of a kitchen or a utility room who actually needs 30A circuits these days?

As someone who has 4x 32A radials in their house, would you mind expanding in that bit please?

 

[Abi Cott]

*not an electrican*

In layman's terms I've been led to believe it's about cables heating up inside the walls.

Radial circuits heat up more than ring mains.

The cables heating up is caused by how much power is being drawn through them. A kettle draws more power than a tv and therefore the cable gets a bit hotter running a kettle than a tv.

Overall not a problem, until you start adding insulation to the areas the cables run through. However if that cable is wrapped in insulating material it can't dissipate the heat and becomes a fire hazard.

However if you add a 16amp fuse instead of a 32 amp fuse to the radial circuit, the fuse blows before the cable reaches a dangerously incendiary temperature.

I'm sure someone more electrically qualified will come along and explain it in more technical terms like "de-rating" but as I understand it, sticking a 16amp fuse in the circuit prevents you from having to worry if a cable that originally was open to the air, now has loft insulation stuffed around it. It's a fairly wise "belt and braces" and given how much less electrical energy most appliances now use it's unlikely to be an inconvenience, but, if, may be, some nutter plugs in 4 electric heaters. The fuse goes pop

 

[Craig89]

A 32A ring circuit would be wired in 2.5mm and a 32A radial would be wired in 4mm cable. An appliance on a ring circuit is essencially supplied with 2 cables in parallel thats why they can be smaller. But as Flyfisher pointed out in most instances these days a 16A supply is more than enough so a 16A radial circuit in 2.5mm cable is perfectly fine.

Radial circuits are prefered because less cable is used and if a ring circuit ever becomes broke for whatever reason then you would have 2 radial circuits feed off an overrated breaker and you would never know. If you have a break in a radial circuit then everything after the break doesnt work which is both safer and easier to fault find

 

[Flyfisher]

Apologies for any confusion, I should have clarified that our cables in question were 2.5mm2 so, as Craig89 has described, a 16A fuse was appropriate for a radial circuit.

I think ring circuits are generally favoured because 2x 2.5mm2 cables are physically easier to install than 1x 4mm2. Not so much in terms of running them in walls and floors etc but connecting 2x 4mm2 cables into a double socket.

There are standardised tables giving the current rating of all cables under different conditions, eg in free air, in conduit, under insulation etc. They are usually quite conservative so rules-of-thumb are frequently used, thus 6A fuse for lighting, 30A fuse for 2.5mm ring mains etc, but in all cases the fuses are there to protect the cable, which in practice means preventing them from overheating.

Incidentally, Abi’s example of someone plugging in four electric heaters would blow either 16A or 32A fuses (assuming 3kW heaters) as they would draw around 50A.

There are guidelines for laying out circuits around a house and how many circuits for a given floor area etc, but this more to do with preventing nuisance tripping rather than absolute safety. It would be perfectly safe in electrical terms to have a whole house served by a single ring or radial circuit but it might not be very convenient if fuses kept tripping.

 

[Abi Cott]

I was assuming they were 2kw heaters :lol: but as stated I'm no electrician. I don't mind doing wiring as long as it's someone else's responsibility to decide what cable goes where.

 

[wobs]

When I got all the main electrical work done on our house in 2013 (almost a full re-wire), our electrician was of the opinion that the standard would eventually go back to radial circuits rather than rings. Not being an electrician, I'm not sure of his reasoning.

As part of this job, we did:
Re-wire of whole lighting circuit, so it was earthed
Extended mains circuits and added various double sockets
Removed some "interesting" wiring and replaced with boring modern wiring.
New consumer unit
Earthed the house.

By the end, we had various old bits left over, including an old isolation switch (probably bakolite). My sister selling them on ebay, but as Flyfisher pointed out, these old units could be dangerous, and as such, wouldn't want to sell them to someone who may use them in a house.

That said, the electrician claimed that modern electrical units were of a lower quality than they used to be. Although if you have an electrical unit that is many over 50 years old, I wouldn't trust that quality owing to wear.

 

[wobs]

.

 

[Flyfisher]

I was assuming they were 2kw heaters :lol: but as stated I'm no electrician. I don't mind doing wiring as long as it's someone else's responsibility to decide what cable goes where.

4 x 2kW = 8000W / 240V = 33.3A (or 34.8A for 230V) so a 32A MCB would still trip, although not instantly in this borderline case because there’s a time/current thing depending on the type of MCB and I don’t know the precise numbers off the top of my head. It’s probably around one minute or so in this example, but the higher the current the faster it will trip. No doubt Mr Google could find the precise details.

The main thing to remember is that the MCB is there to protect the cable from overheating and if properly matched everything should be safe, regardless of how many things are plugged in at any one time.

 

[Flyfisher]

When I got all the main electrical work done on our house in 2013 (almost a full re-wire), our electrician was of the opinion that the standard would eventually go back to radial circuits rather than rings. Not being an electrician, I'm not sure of his reasoning.

Interesting. I’d guess it’s because, outside of kitchens, very few devices these days are high power so a 30A circuit is overkill in most cases. It would also save cable and copper, so a bit more eco-friendly.

In practice, I’d say the modern requirement is for many more sockets rather than lots of power, which no doubt why those plug-in ‘socket strips’ are so popular these days. I have about 10 sockets in my study but I doubt I’m using more than 3A even with everything switched on!