120 V 230 Volts mains, which is best?

[boater sam]

The ring main is not compulsory, radial circuits can be used. But the ring has the advantage that the cable rating is effectively 40 Amp with a 30 or 32 Amp fuse/MCB. It is more difficult to overload a ring, the heat has more space to dissipate from two cables rather than one.
I prefer to put two or more wires in a connector rather than just the one.

[colly0410]

Been thinking: Many years ago when they twigged that 230'ish volts was a more economic mains system than 110'ish volts, most 110 V countries changed over to 230 V, but not the USA. Did the USA hold on to 110 V for protectionist reasons?

[Terry]

Remember reading somewhere that ring mains can only be safely used with fused plugs otherwise a faulty short circuited gubbins would get the full 30 amps, wereas with a 13 or 3 amps fused plug the max current would be err 13 or 3  amps in theory..

I used to think on similar lines but that isn't right.

The 30A fuse/32A breaker in the consumer unit protects the ring.

The plug fuse protects the cable connected to it so, if you are using 0.5mm² flex rated at 3A, you shouldn't fit a fuse larger tha 3A.

0.75mm² is rated at 6A and 1mm² at 10A. You should be using 1.25mm² or heavier flexible cable if a 13A fuse is fitted.

As for the equipment at the far end of the flex, it is the manufacturers responsibility to provide protection for that. Hence a wallwart doesn't have a replaceable fuse, although it is essentially a 13A plug because there is no flex to protect. There should, however, be internal protection* inside the (sealed) case. It isn't replaceable because you can't get inside!

* Whether there is or not in a lot of cheap stuff imported from China is, of course, another matter ...

[colly0410]

In our hotel room in America we had 2 bedside lamps & each had a 129 volts socket & 2 USB ports built into them, never seen this before. ..

[Terry]

I presume you meant 120V but hit the wrong key!

Not unusual to find 13A sockets like that in the UK.

I picked up a handy unit in Poundland recently which plugs into a 13A socket and has two USB ports and a 13A socket.

It will be handy on holidays and saves taking two chargers with us, as well as leaving the socket available for use.

We're going to the Netherlands next month so, coupled with a 13A to Schuko adaptor, it should prove very useful indeed.

[ppppenguin]

I picked up a handy unit in Poundland recently which plugs into a 13A socket and has two USB ports and a 13A socket.

There is some cause for concern about the USB sockets built into 13A socket outlets which sell for £8 and up. It makes me  wonder how a safe and adequate USB charger can be sold for £1. Or is it one of their few items at rather more. Even at £2 I still don't see how you can possibly make a saef device like that.

Mind you, I've bought Poundland's 3 way 13A blocks and they seem to be OK, at least for light loads.

[colly0410]

Yes finger slipped, should have been 120 volts... Seen USB ports in sockets here, but never a power socket built into a bedside lamp base. Took a photo & posted it on my FB page & even my American friends had never seen it before...

[ppppenguin]

Going back to ring vs radial wiring. i haven't seen the 18th edition wiring regs but I think that rings are now deprecated. I think one reason is the addtional time and effort needed to fully verify a ring final when testing an intallation. A ring final will also carry on working with a break in the ring but is then liable to overheating. The standard circuits for sockets are now radials. 20A with 2.5m cable and 32A with 4mm cable.

An article on the pros and cons of ring finals. Hideous font: https://gadsolutions.biz/electrical-serv...n-good-bad

[Terry]

Apologies - I hadn't spotted that these sockets were in the lamp itself. Perhaps I should practice reading slower so that I take in all the words!

Jeffrey: yes, I think it was one of their £2 items - I might take it apart later.

I also picked up a slightly different 13A to Schuko adaptor at the same time. It is much deeper than others I have and is a more refined design. Usually the edge of the 13A earth pin forms one of the Schuko side contacts. The French/Belgian earth socket then has to go on the other side of the line and neutral pins which means that, when used in one of these countries, the 13A socket is upside down!

This one uses the extra depth to correct for this so that the 13A earth pin is entirely contained in the adaptor and the socket will be the right way up!

[Terry]

Correction: the usb charger/13A socket is branded Silver Crest, so came from the middle of Lidl. Incidentally, the charger delivers up to 3.4A.

Both it and the adaptor are held together by 3 wing Phillips type screws and I've no idea where my box of special bits is at the moment, so internal inspection will have to wait for now.