In-line dual-pole RCBO for extension leads?

[unopened]

Hi all,

My internet searching skills seem to be sadly lacking, so I'll apologise if there is as easy solution I've not found.

I do a fair amount of travel abroad, and need to carry (mostly) IT equipment, some of which is powered by wall-warts - transformers moulded into UK plugs, so I can't simply swap mains leads. What I'd like to do is find an in-line RCBO so that I can take an n-way extension, chop off the plug and attach a Schuko-style plug and and RCBO. Then I can get rid of my collection of Schuko-to-BS1363 adapters and assorted mains leads and travel with a standard set of kit that never needs changing.

The reason I want dual pole is that the polarity of the live and neutral is not guaranteed with Schuko - indeed, in some double sockets it is guaranteed they will be different.

I think I want an RCBO as, in theory, 'continental' wiring can deliver

16A quite happily, and given that the UK stuff is rated to 13A, I'd like to put in a 10A RCBO.

I have found in-line RCDs, but no RCBOs. An alternative (probably cheaper) approach might be to use the RCD and put in a couple of in- line 13A fuses in the extension lead. I realise that fusing a neutral is normally a no-no, but since I can't tell which is live and which is neutral, it seems like the best approach. Do such things as 13A in- line fuseholders exist? And come to that (although not relevant for this query) in-line dual pole 13A switches? I can find single-pole 'torpedo' switches rated to 3A, but nothing higher.

Cheers,

Sid

[Toby]

The multi-way socket strip should have a fuse, so could you just get one of these

if your L&N is reversed, you can just unplug and re-plug the Schuko the other way round?

Toby...

[meow2222]

or fit 3 neons into the multiway socket to do the same job. Much neater. Then you just want an RCD.

NT

[John Rumm]

There is no point in fusing both live and neutral since only one will blow on an overload, and you won't know which. The one 13A fuse will serve to limit the maximum current, hence you can skip the RCBO bit of the requirement, and just go for a RCD.

NT's suggestion of neons is quite a simple and effective way to check the polarity. One between each side of the supply and earth should tell you what you need to know (you could leave the existing neon found in most 4 way leads as a "power good" indicator, and then add another betwixt neutral and earth as a "polarity reversed" one)

[meow2222]

Or one neon only as a polarity reverse warning. But can you always rely on a good earth?

NT

[Dave Plowman (News)]

Doesn't make a scrap of difference to any of your likely equipment. I can't think of any appliances where swapping line and neutral would cause problems with either operation or safety. So just use an RCD fused at an appropriate level. A Schuko plug in one would be ideal.

[John Rumm]

Depends on the sort of place you are plugging it into I suppose. Have another from live to neutral if in doubt.

[unopened]

I can't always rely on a good earth, unfortunately. Do socket testers reliably indicate live and neutral reversal if there is no earth? I don't quite see how. If so, using the socket tester in the extension sockets is inspired - thank-you.

I already have in-line RCDs, so I think a trip to Screwfix (I have one within walking distance) is in order for a socket tester and another multi-way extension.

I prefer to use an in-line RCD as it is more versatile that the moulded-plug variety - I've often found sockets where it is not possible to plug in a moulded-plug RCD or wall-wart - e.g. the sockets found under floor plates in conference and/or meeting rooms, or sockets with furniture or decor in the way - having a small right angle Schuko is essential in such cases.

Many thanks for all the replies.

Sid

[John Rumm]

You would have to query the manufacturer. Most of them state they can't detect a neutral earth transposition, but handle the remainder of the faults. However they can oly usually show one fault at a time, so it may well be that the lack of earth would be flagged as the first fault, and you would not get to see the polarity reversal fault until after clearing the first one.

I was thinking of just adding "mains ready" neons to a trailing socket rather than using a full blown plug in tester. However that would also do the job.

[gazz]

yay, someone with sense replies :)

i'd imagine 99% of his wall warts dont need an earth, and as for polarity, why would they care, if you had the shuko version it could be plugged in either way round, so why does having a 13 amp plug on it make it 'special' :)

as for the rcd.... almost all wall warts have some sort of protection built in, and any power you can be exposed to will be after the wart, so will be low voltage prolly DC, so the rcd wont do owt anyway.

just make up an extension with a dual country shuko on it (with the earth strips for germany, and the hole for the earth pin for france) and your covered for most places in europe, caravan shops should sell the dual earth plug if your really stuck, but of course if you never want to plug into french power, then dont bother and get a plain old german shuko, (btw, even tho frances shuko's are polorised, they rarely wire the sockets up with any polarity consistancy)

[BigWallop]

You can buy a UK Extension and fit a Schuko lead to it. I say a Schuko Lead, because I don't know of any UK supplier that will just have the plugs. They have to be moulded to the appliance lead the same as the UK now. But you can probably buy a Schuko kettle (clover) lead for around 4 or 5 pounds.

Remove the UK setup on the extension and fit the new Schuko lead in its place. You're working with the same AC (or as near as damn it) as we do in the UK. Either way round, it has to work. Even your small PSU's. Now you have a Schuko plug to 13 amp fused UK two, three, four, five, six, seven or eight way extension socket.

Schuko appliance leads are sold only in the earthed version in the UK. Our regulations make it mandatory for the leads sold in the UK to be earthed. :-)

Good luck with it.

[Owain]

Would a power strip with a built in RCD help?

"panel mounted fuse holder and

30mA RCD"

They also do them with individually fused sockets

bespoke with a range of options, though that might be pricy. "Customer specified sockets, including combinations of different sockets UK 13A (BS1363), IEC320 C13 10A, IEC320 C19, IEC309 16A and 32A, USA, German, French, Swiss, Italian, Neutrik, Electrak Customer specified options such as switches, circuit breakers, fuses, neon indicators, meters, rf filters, sequential start timers"

Owain

[Andrew Gabriel]

One comment I'd make is that RCD's are fragile devices and usually fail unsafe. If you have one as part of portable equipment, make sure you always test it when you are setting up, and at frequent intervals whilst in use. Otherwise, you will be unaware when it's been dropped and no longer trips off. For this reason, I never buy the type which is built in to a plug. People treat them like plugs in terms of dropping, bashing, kicking, etc, and they don't survive that.

[Dave Plowman (News)]

We use loads of them for location filming and they seem to survive quite well.

[Dave Liquorice]

Agreed, most wall warts are double insulated and earth less.

I think the OP was concerned about single pole switching in a system were polarity is not fixed. ie the trip goes but equipment is still live. In the "heat of the moment" it is all to easy to forget to unplug apparently dead kit before working on the fault.

But aren't some continental sockets earthless and/or have a bi-phase supply? Which poses some interesting questions regarding the KISS plugin tester and rotate the plug approach.

[unopened]

Would a power strip with a built in RCD help?

"panel mounted fuse holder and

30mA RCD"

They also do them with individually fused sockets

bespoke with a range of options, though that might be pricy. "Customer specified sockets, including combinations of different sockets UK 13A (BS1363), IEC320 C13 10A, IEC320 C19, IEC309 16A and 32A, USA, German, French, Swiss, Italian, Neutrik, Electrak Customer specified options such as switches, circuit breakers, fuses, neon indicators, meters, rf filters, sequential start timers"

Thanks Andrew, thanks Owain.

I should have looked at Olsen - I've specified them in datacentres often enough, usually bespoke. I've not been the one paying.

I usually test RCDs pretty much every time I energise them - just got into the habit. Perhaps I've been lucky, but I've not had one fail yet. I take the point about being fragile, 'though. Knocking about in checked baggage is not the most benign of environments. Anything brittle gets double wrapped in bubble wrap, and I make sure the suitcase is stuffed to prevent rattling about. A friend of mine told me to pack as if the suitcase were to be thrown from the second storey of a building, which seems to work, and having often watched baggage handlers load and unload, I see what luggage gets put through.

Sid

[unopened]

Dave - you are reading my mind. As I get older, the chances of me forgetting to isolate before investigating the fault get higher. You could say from a Darwin Award point of view, it would serve me right, but alas, I'm too old to qualify.

As for continental sockets, you are quire right, and what would be regarded in the UK as dangerous practices abound. In Italy, I came across a multi-way CEE 7/7 trailing adaptor wired into a CEE 7/16 plug (hidden away behind a filing cabinet), which was powering everything in a meeting room - including the (very hot) projector and multiple laptops. Similarly, in Denmark, a multiway CEE 7/7 serving several other multiway adapters.

Norway has many CEE 7/17 sockets in older buildings (Like Schuko, but no earth slides or pins), which is problematic as many higher power laptop power transformers supplied in the UK seem to want functioning earths - they are certainly wired as such.

I think bi-phase is/was used a lot in Scandinavia and Germany.

Like many things, this seems to get more complicated the more I look at it. At least I don't (yet) travel to the USA.

As life goes on, I keep on finding more things to be ignorant about!

Regards,

Sid

[meow2222]

Then you need the full set of 3 neons, as used in plug-in testers.

They're just 3 neons, L-N, N-E, E-L. So they'd indicate all wasnt right, but cant tell you exactly whats going on if there are 2 simultaneous faults.

NT

[Dave Liquorice]

One "fault" could be no earth at the socket... And being neons you may still get illumination, via leakage, in the abscence of a real earth. Or the "delta" connected neons would make the floating earth point rise to

50% of the L-N voltage which would provide enough volts for the neons to light at a lower level compared to the one L-N but that might not be particulary obvious.

I wonder of the better quality plugin testers use LEDs and high voltage zeners?

[meow2222]

Yes, both neons light, the fault shows up.

NT