I'm in the middle of wiring up a cable for an electrical hook up to be
used while camping in France. I have a French 3-pin plug bought there
on a previous visit, but in opening it up I find there's absolutely no
indication which of the two power pins is live and neutral. Doesn't it
matter?

I will be using the cable with an RCD device; won't that object and trip
out if the wiring's the wrong way round? Or is it a case of "suck it
and see" when I get to France, and if it's wrong, reverse the wiring?

Thanks
David

"Lobster" wrote in message
...
I'm in the middle of wiring up a cable for an electrical hook up to be
used while camping in France. I have a French 3-pin plug bought there on
a previous visit, but in opening it up I find there's absolutely no
indication which of the two power pins is live and neutral. Doesn't it
matter?

I will be using the cable with an RCD device; won't that object and trip
out if the wiring's the wrong way round? Or is it a case of "suck it and
see" when I get to France, and if it's wrong, reverse the wiring?

Thanks
David

You can get the proper adaptor from a caravan shop or Towsure, but be
careful some sites in France use the same blue plug as our sites, I have 3
different adapters - two with the French plugs, one with reversed polarity
and the other as normal then I also have a short lead of male and female
blue plugs with the polarity reversed because 'yes' I have come across that
aswell! Its also useful having a blue plug with a uk three pin socket on the
end so you can plug a tester in to test for correct polarity or earth faults
before using the correct adaptor to hook up.
Steve.

In article ,
Lobster writes:
I'm in the middle of wiring up a cable for an electrical hook up to be
used while camping in France. I have a French 3-pin plug bought there
on a previous visit, but in opening it up I find there's absolutely no
indication which of the two power pins is live and neutral. Doesn't it
matter?

If you're referring to the standard french domestic socket
outlet, it's not defined which way around the live and neutral
are. Actually, on most 2-way adaptors and double socket outlets,
you'll find the two sockets are hard-wired internally the opposite
way around.

I will be using the cable with an RCD device; won't that object and trip
out if the wiring's the wrong way round?

Some do, but I don't think that's a common feature.

Or is it a case of "suck it
and see" when I get to France, and if it's wrong, reverse the wiring?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

KHBlue wrote:

"Lobster" wrote in message
...
I'm in the middle of wiring up a cable for an electrical hook up to be
used while camping in France. I have a French 3-pin plug bought there
on a previous visit, but in opening it up I find there's absolutely no
indication which of the two power pins is live and neutral. Doesn't
it matter?

I will be using the cable with an RCD device; won't that object and
trip out if the wiring's the wrong way round? Or is it a case of
"suck it and see" when I get to France, and if it's wrong, reverse the
wiring?

You can get the proper adaptor from a caravan shop or Towsure, but be
careful some sites in France use the same blue plug as our sites, I have
3 different adapters - two with the French plugs, one with reversed
polarity and the other as normal then I also have a short lead of male
and female blue plugs with the polarity reversed because 'yes' I have
come across that aswell! Its also useful having a blue plug with a uk
three pin socket on the end so you can plug a tester in to test for
correct polarity or earth faults before using the correct adaptor to
hook up.

Thanks for that. What a palaver! Yes, I already have a conventional
UK-style cable with blue plug; what I'm actually wiring today is a short
adapter, ie with a blue socket to a French plug.

Hmm, a plug-in tester sounds a good idea, now. However, I'm not going
to have time to sort out further hardware as I leave for France tomorrow
- so in the meantime can you or anyone else confirm what happens if I
plug in the cable with accidentally reversed polarity? Will it just
trip the RCD device, so I can just rewire the plug? If not, what will
be the effect of getting it wrong... electrical items to be used include
a fridge, laptop, phone chargers...

Thanks
David

Lobster wrote:
I'm in the middle of wiring up a cable for an electrical hook up to be
used while camping in France. I have a French 3-pin plug bought there
on a previous visit, but in opening it up I find there's absolutely no
indication which of the two power pins is live and neutral. Doesn't it
matter?

I will be using the cable with an RCD device; won't that object and trip
out if the wiring's the wrong way round? Or is it a case of "suck it
and see" when I get to France, and if it's wrong, reverse the wiring?

Thanks
David
A number of years ago when caravanning in France/Spain I was warned by a
friend about polarity problems when using an RCD. I fitted a switch
(DPDT) the the (old) van so that I could easily change polarity. Sure
enough on one site in France when a new arrival plugged my leadinto a
different socket on the same set of sockets I discovered that the system
had trippedbecause the polarity was reversed. On a site in Spain this
polarity reversal happened without the lead being unplugged!

You need three adaptors
16A blue to 16 A blue, polarity reversed
16A blue to continental
16A blue to continental, polarity reversed

If the RCD trips and won't reset, reverse the polarity. Our continental
cousins don't have the concept of live and neutral that we do

Malcolm

Lobster wrote:
KHBlue wrote:

"Lobster" wrote in message
...
I'm in the middle of wiring up a cable for an electrical hook up to
be used while camping in France. I have a French 3-pin plug bought
there on a previous visit, but in opening it up I find there's
absolutely no indication which of the two power pins is live and
neutral. Doesn't it matter?

I will be using the cable with an RCD device; won't that object and
trip out if the wiring's the wrong way round? Or is it a case of
"suck it and see" when I get to France, and if it's wrong, reverse
the wiring?

You can get the proper adaptor from a caravan shop or Towsure, but be
careful some sites in France use the same blue plug as our sites, I
have 3 different adapters - two with the French plugs, one with
reversed polarity and the other as normal then I also have a short
lead of male and female blue plugs with the polarity reversed because
'yes' I have come across that aswell! Its also useful having a blue
plug with a uk three pin socket on the end so you can plug a tester in
to test for correct polarity or earth faults before using the correct
adaptor to hook up.

Thanks for that. What a palaver! Yes, I already have a conventional
UK-style cable with blue plug; what I'm actually wiring today is a short
adapter, ie with a blue socket to a French plug.

Hmm, a plug-in tester sounds a good idea, now. However, I'm not going
to have time to sort out further hardware as I leave for France tomorrow
- so in the meantime can you or anyone else confirm what happens if I
plug in the cable with accidentally reversed polarity? Will it just
trip the RCD device, so I can just rewire the plug? If not, what will
be the effect of getting it wrong... electrical items to be used include
a fridge, laptop, phone chargers...

Thanks
David
RCD devices only look for a difference in the current flowing in the two
connections. It has nothing to do with earth. You may however find that
the test button does not work if L & N are reversed as I think all this
does is to connect a resistor between the live and earth. This might
only provide enough trip current if the live is truly live.

Bob

On Sat, 2008-08-30 at 19:45 +0100, Malcolm wrote:
Lobster wrote:

You need three adaptors
16A blue to 16 A blue, polarity reversed
16A blue to continental
16A blue to continental, polarity reversed



Surely the first two together are equivalent to the third, so you only
really *need* two adaptors?

Mike

Malcolm wrote:
Lobster wrote:
I'm in the middle of wiring up a cable for an electrical hook up to be
used while camping in France. I have a French 3-pin plug bought there
on a previous visit, but in opening it up I find there's absolutely no
indication which of the two power pins is live and neutral. Doesn't
it matter?

I will be using the cable with an RCD device; won't that object and
trip out if the wiring's the wrong way round? Or is it a case of
"suck it and see" when I get to France, and if it's wrong, reverse the
wiring?

Thanks
David
A number of years ago when caravanning in France/Spain I was warned by a
friend about polarity problems when using an RCD. I fitted a switch
(DPDT) the the (old) van so that I could easily change polarity. Sure
enough on one site in France when a new arrival plugged my leadinto a
different socket on the same set of sockets I discovered that the system
had trippedbecause the polarity was reversed. On a site in Spain this
polarity reversal happened without the lead being unplugged!

You need three adaptors
16A blue to 16 A blue, polarity reversed
16A blue to continental
16A blue to continental, polarity reversed

If the RCD trips and won't reset, reverse the polarity. Our continental
cousins don't have the concept of live and neutral that we do

OK, thanks - think I've got it now! Will organise some more hardware
before my next trip.

I don't intend to use any power without an RCD, but just for my
education and information, if I *were* to do so, would all my kit
(laptop/fridge/chargers) all work OK without problems, then?

What do the French etc do about this polarity problem - do they not
bother with RCDs while camping or whatever?

David

cousins don't have the concept of live and neutral that we do

OK, thanks - think I've got it now! Will organise some more hardware
before my next trip.

I don't intend to use any power without an RCD, but just for my education
and information, if I *were* to do so, would all my kit
(laptop/fridge/chargers) all work OK without problems, then?

What do the French etc do about this polarity problem - do they not bother
with RCDs while camping or whatever?

David

Generally reverse polarity will make little difference to 230 volt
appliances in good working order. The problem with UK appliances occurs if
the appliance has a fault and remains on when you think it is off as we only
switched on the live side. Mind you newer caravans don't seem to have socket
switches now which makes it a bit more difficult. If its any help this is
how I have explained it on my website
http://www.davidklyne.plus.com/frenc...anelectric.htm The best option
is the have a short cable with CEE17 male and sockets at either end with one
end reversed. This can then be used with either you manin cable or with the
continental adaptor. At least that works for me. Have a good trip.

David - Milton Keynes
www.caravantravels.co.uk

In message , Lobster
writes
Malcolm wrote:
Lobster wrote:
I'm in the middle of wiring up a cable for an electrical hook up to
be used while camping in France. I have a French 3-pin plug bought
there on a previous visit, but in opening it up I find there's
absolutely no indication which of the two power pins is live and
neutral. Doesn't it matter?

I will be using the cable with an RCD device; won't that object and
trip out if the wiring's the wrong way round? Or is it a case of
"suck it and see" when I get to France, and if it's wrong, reverse
the wiring?

Thanks
David
A number of years ago when caravanning in France/Spain I was warned
by a friend about polarity problems when using an RCD. I fitted a
switch (DPDT) the the (old) van so that I could easily change
polarity. Sure enough on one site in France when a new arrival
plugged my leadinto a different socket on the same set of sockets I
discovered that the system had trippedbecause the polarity was
reversed. On a site in Spain this polarity reversal happened without
the lead being unplugged!
You need three adaptors
16A blue to 16 A blue, polarity reversed
16A blue to continental
16A blue to continental, polarity reversed
If the RCD trips and won't reset, reverse the polarity. Our
continental cousins don't have the concept of live and neutral that we
do

OK, thanks - think I've got it now! Will organise some more hardware
before my next trip.

I don't intend to use any power without an RCD, but just for my
education and information, if I *were* to do so, would all my kit
(laptop/fridge/chargers) all work OK without problems, then?

What do the French etc do about this polarity problem - do they not
bother with RCDs while camping or whatever?

David

As has already been said, the RCD looks for a difference in the currents
in the live and neutral. If there is an imbalance, it assumes the
current is flowing to earth somewhere (which it should not be) and trips
out. Therefore it will make no difference which way round the device is
connected. Also, the connected equipment cannot "tell" which way round
it is wired - the current is alternating! In the UK we like to know
which is which for safety reasons - if we switch off equipment by
breaking the neutral, the equipment will be off but still at live
potential which could be dangerous for anyone poking about inside.
However as much of Europe uses 2 pin reversible plugs it can obviously
be connected either way.
--
John Mann

In article ,
Malcolm wrote:
If the RCD trips and won't reset, reverse the polarity.

That suggests a fault elsewhere in *your* wiring or appliances. RCDs ain't
'polarity' sensitive.

Our continental
cousins don't have the concept of live and neutral that we do

That's because there's no such thing as polarity with AC - unless you
ground one leg as the UK does. Not all countries do.

--
*The average person falls asleep in seven minutes *

Dave Plowman London SW
To e-mail, change noise into sound.

Andrew Gabriel wrote:

If you're referring to the standard french domestic socket
outlet, it's not defined which way around the live and neutral
are.

I'm really amazed at the low standard of Italian plugs.
It makes one wonder if the fuses in UK plugs are really necessary.
There are meant to be two kinds of 3-pin plugs, for power and lights,
but all the sockets I have seen accept either.

Has there been any EU attempt to define a European standard plug?


--
Timothy Murphy
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

"Dave Plowman (News)" wrote in message
...
That's because there's no such thing as polarity with AC - unless you
ground one leg as the UK does. Not all countries do.

Now, that's a whole can of worms I never really got my head round.

*Why* do we have one leg ( Neutral ) referenced to earth?

The down-side is that if an appliance develops a fault such that the case
becomes 'live', an earthed person gets a whack. We then go to great
lengths to earth the cases ets etc, so that fault current will trip
something, clearing the danger.

Why don't we float the whole system WRT earth?
Then it doesn't matter if an appliance becomes 'live' WRT earth.

Aside:
I just got back from Namibia and Botswana.
I was peering at their overhead 11Kv distributution system.
All very similar to here.
With an interesting exception.

There were long runs of *single* conductor HV on poles, along the rural
gravel roads.
There were transformers dotted around on poles, feeding individual premises.
I never got a good look at one of these transformers.
Now, how does that work?
They must be using TT earth as an actual current return, on the HV side, as
far as I can see.
I wonder how they make the local HV earth connection with sufficiently low Z
in the very dry earth?

Further confirmation was at one lodge, where an old transformer was laying
outside the services building. ( I'm sure everyone thought I was crazy,
polishing the muck of the data plate of an old transformer in the corner.. )
The rating plate had the single phase primary as 6.3Kv, which is consistent
with the Phase-N voltage of an 11Kv Phase-Phase system. There must have
been 1:1 Star-Delta transformers someplace on the main network, where the
normal 11 KV 3-wire delta distribution spurred off to a star 11Kv 3-wire +N
( 6.3Kv per phase-N ), and the N was grounded. Only the single phase was
sent on the wire.

Interesting to me, anyway.

--
Ron

On Sat, 30 Aug 2008 23:02:59 +0100, "Ron Lowe"
ronATlowe-famlyDOTmeDOTukSPURIOUS wrote:

"Dave Plowman (News)" wrote in message
...
That's because there's no such thing as polarity with AC - unless you
ground one leg as the UK does. Not all countries do.

Now, that's a whole can of worms I never really got my head round.

*Why* do we have one leg ( Neutral ) referenced to earth?
The reason for earthing one side of the mains is that by so doing, you
prevent the mains from floating to a dangerous voltage due to leakage
in the substation transformer, or indeed faulty appliances owned by
somebody else off the same feed.

--
Frank Erskine

In article ,
Timothy Murphy writes:
Andrew Gabriel wrote:

If you're referring to the standard french domestic socket
outlet, it's not defined which way around the live and neutral
are.

I'm really amazed at the low standard of Italian plugs.
It makes one wonder if the fuses in UK plugs are really necessary.
There are meant to be two kinds of 3-pin plugs, for power and lights,
but all the sockets I have seen accept either.

Has there been any EU attempt to define a European standard plug?

Several, all failed (except for standardising a 2-pin plug which
we don't use in the UK), although I may be out of date now.

Basically, no one is prepared to change, and everyone believes
(without any evidence to back it up) that theirs is the best system.
It's not just the plug -- the design of that is linked to the
design of the electrical distribution and protection systems, and
these vary widely across Europe. The UK BS1363 (13A) plugs and
sockets are the most recent of the established designs for mains
appliance plugs and sockets in the world (1946). All other systems
predate that, some by a very long way. BS1363 is also quite widely
adopted around the world, although in Europe, only in UK, Ireland
and Malta.

I loosely followed the first attempt. EEC (as it then was) placed
the requirement than the new plug/socket had to be different from
anything currently existing so no country derived unfair commercial
benefit (and there are good technical reasons for that too), and it
had to be no less safe than any of the existing schemes. That got
nowhere. Last I heard (which was probably at least 6 years ago),
there had been 5 attempts, all failed. In practice, standardisation
has taken place at the other end of the cable, i.e. the IEC mains
inlet connectors.

In the commercial arena, the british commando BS4343 plugs and
sockets have been universally adopted as no other European country
had anything much of an equivalent standard. Even the US have
adopted a variant of them (different ratings).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Frank Erskine" wrote in message
...
On Sat, 30 Aug 2008 23:02:59 +0100, "Ron Lowe"
ronATlowe-famlyDOTmeDOTukSPURIOUS wrote:

"Dave Plowman (News)" wrote in message
...
That's because there's no such thing as polarity with AC - unless you
ground one leg as the UK does. Not all countries do.

Now, that's a whole can of worms I never really got my head round.

*Why* do we have one leg ( Neutral ) referenced to earth?
The reason for earthing one side of the mains is that by so doing, you
prevent the mains from floating to a dangerous voltage due to leakage
in the substation transformer, or indeed faulty appliances owned by
somebody else off the same feed.

--
Frank Erskine


I'll need to think about that.

What does "floating to a dangerous voltage" mean?
To a dangerous voltage with respect to what?
Earth?
A floating system has undefined voltage WRT earth.

I'm trying to imagine an actual fault scenario, where a floating L-N pair
can float to a 'dangerous voltage' WRT earth. If the whole system is
floating, then there's no such thing as a 'dangerous voltage'.

Hmm, perhaps if one leg leaks to earth at the substation, then the system no
longer floats, and there's the possibility of shock WRT earth.

Need to think some more.

--
Ron

In article ,
"Anthony R. Gold" writes:
On Sat, 30 Aug 2008 23:12:16 +0200, Timothy Murphy
wrote:

I'm really amazed at the low standard of Italian plugs.
It makes one wonder if the fuses in UK plugs are really necessary.

If they don't use a ring mains configuration but a radial system, such as
used in the USA, then wiring can be safely configured without plug fuses.

Did you realise you put the words _US_, _wiring_, and _safely_ in
the same sentence?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Frank Erskine" wrote in message
...
On Sat, 30 Aug 2008 23:02:59 +0100, "Ron Lowe"
ronATlowe-famlyDOTmeDOTukSPURIOUS wrote:

"Dave Plowman (News)" wrote in message
...
That's because there's no such thing as polarity with AC - unless you
ground one leg as the UK does. Not all countries do.

Now, that's a whole can of worms I never really got my head round.

*Why* do we have one leg ( Neutral ) referenced to earth?
The reason for earthing one side of the mains is that by so doing, you
prevent the mains from floating to a dangerous voltage due to leakage
in the substation transformer, or indeed faulty appliances owned by
somebody else off the same feed.

UK Electrical workmanship standards differ from Europe we have neutral and
earth return, The europeans don't have an earth linked into the
substation/generating station neutral as we do. in fact they don't use
earth return at all.

I was involved with a transformer company a few years ago which used to
manufacture mains test lamps for amongst others RS componants ,very simple
if there was voltage they lit up, cost pennies and all the electricity
boards used them.

Overnight the EEC brought in rules on the test equipment that could be used
, they cost about £50 each, (I am sure due to pressure from a German test
manufacturer), but due to the differing workmanship practices in the UK were
not as efficient. Our observant Goverment didn't even notice!! (or didn't
realise the impact), nearly put the company out of business (CE mark and
Insurance) Eventually they managed to get an exemption to the rules for a
few years.

Most modern mains electrical equipment is double insulated and doesn't
matter which way round it is wired (live/neutral), don't forget it gets
supplied to Europe as well. If you are concerned get a polarity live/neutral
tester and carry adapter plugs wired to suit both polarities.

Des

On Sat, 30 Aug 2008 19:50:39 +0100, Bob Minchin wrote:

RCD devices only look for a difference in the current flowing in the two
connections. It has nothing to do with earth.

Yep. RCD's tripping with the "wrong" polarity strikes me as an big
indication that something isn't quite what it should be with the caravan
wiring.

You may however find that the test button does not work if L & N are
reversed as I think all this does is to connect a resistor between the
live and earth. This might only provide enough trip current if the live
is truly live.

I should hope it places a resistor between L and N and across the current
transformer. So that it actually tests what it is supposed to be doing
rather than relying on another path that might not exist.

L ------ CT -------+---
|
+-- R -- TB --+ LOAD
|
N ---+-- CT -----------

--
Cheers
Dave.

In article ,
"Anthony R. Gold" writes:
On 30 Aug 2008 22:38:31 GMT, (Andrew Gabriel)
wrote:

In article ,
"Anthony R. Gold" writes:
On Sat, 30 Aug 2008 23:12:16 +0200, Timothy Murphy
wrote:

I'm really amazed at the low standard of Italian plugs.
It makes one wonder if the fuses in UK plugs are really necessary.

If they don't use a ring mains configuration but a radial system, such as
used in the USA, then wiring can be safely configured without plug fuses.

Did you realise you put the words _US_, _wiring_, and _safely_ in
the same sentence?

Do you have any data or statistics to show that they do not deserve to fit
into the same sentence?

There's plenty of it around. Their deaths per capita arising from
electrical causes is significantly worse than UK and much of Europe.
This is nothing to do with a radial system (which is implemented
very safely in many places). It's to do with the poor quality of
their wiring accessories, connections, breakers, etc, combined with
higher current heating effects due to lower mains voltage. This is
also amplified by the more significant use of entirely timber
(flammable) building construction in many areas.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Anthony R. Gold wrote:

Anthony R. Gold wrote:
If they don't use a ring mains configuration but a radial system, such as
used in the USA, then wiring can be safely configured without plug fuses.
Whether the wiring is radial or ring makes no difference. What is
important is that fused plugs allow circuit protection at a higher
rating than would be permitted for individual appliances.

I disagree; with a radial system it is possible to protect the appliance
cord at the distribution circuit breaker. That is not possible with a ring
main.

Why not? If you protected your circuit with a 16A MCB (be it radial or
ring) then the appliance flex would be protected at the origin of the
circuit.

You would of course also end up with a bunch of piddly little circuits
not at all well suited to today's pattern of usage.

If we didn't have fused plugs then circuit protection would have to be
at 16A and we would have the problem that they do have in the USA that
if you plug two high power appliances into the 'wrong' combination of
sockets on various circuits the MCB trips.

The fact that an MCB might trip does not demonstrate the system is unsafe.

No, just that the design is not really fit for purpose.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Lobster wrote:

I'm in the middle of wiring up a cable for an electrical hook up to
be used while camping in France. I have a French 3-pin plug bought
there on a previous visit, but in opening it up I find there's
absolutely no indication which of the two power pins is live and
neutral. Doesn't it matter?

I will be using the cable with an RCD device; won't that object and
trip out if the wiring's the wrong way round? Or is it a case of
"suck it and see" when I get to France, and if it's wrong, reverse
the wiring?

Frankly I've found it doesn't, in practice, matter what you use.
Sister took about four different cables to cover all 'reversed wiring'
possibilities, along with a tester , and took about an hour to figure
it all out to her satisfaction. We just plugged in and that was it.

We know for certain that one of the sites was reverse polarity, so all
we did was not leave stuff, phone charger etc, plugged in!

s'easy ...

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi 'Big and Butch'
Dyna Tech Cro-Mo comp "When I feel fit enough'

Ron Lowe wrote:
"Dave Plowman (News)" wrote in message
...

snip

Aside:
I just got back from Namibia and Botswana.
I was peering at their overhead 11Kv distributution system.
All very similar to here.
With an interesting exception.

There were long runs of *single* conductor HV on poles, along the
rural gravel roads.
There were transformers dotted around on poles, feeding individual
premises. I never got a good look at one of these transformers.
Now, how does that work?
They must be using TT earth as an actual current return, on the HV
side, as far as I can see.
I wonder how they make the local HV earth connection with
sufficiently low Z in the very dry earth?

Further confirmation was at one lodge, where an old transformer was
laying outside the services building. ( I'm sure everyone thought I
was crazy, polishing the muck of the data plate of an old transformer
in the corner.. ) The rating plate had the single phase primary as
6.3Kv, which is consistent with the Phase-N voltage of an 11Kv
Phase-Phase system. There must have been 1:1 Star-Delta
transformers someplace on the main network, where the normal 11 KV
3-wire delta distribution spurred off to a star 11Kv 3-wire +N (
6.3Kv per phase-N ), and the N was grounded. Only the single phase
was sent on the wire.
Interesting to me, anyway.

Uses the Earth (the real solid one you stand on) for the return. Works well
most of the time except when the weather is very dry then you get brown outs
................. (well you would if there is no rain!)

--
Mark BR

Timothy Murphy wrote:

It makes one wonder if the fuses in UK plugs are really necessary.


UK plug fuses are there to reduce (but not eliminate) the risk of fire
caused by an appliance. They don't protect people, as you would be
dead long before a fuse blew.

Mainland European installations have relied on RCDs for many years. An
RCD protects people, not appliances, so you aren't likely to be
electrocuted thanks to a flimsy plug, although there may be a slightly
higher fire risk (or so I am told).

In article ,
Bruce writes:
Timothy Murphy wrote:

It makes one wonder if the fuses in UK plugs are really necessary.


UK plug fuses are there to reduce (but not eliminate) the risk of fire
caused by an appliance.

Actually, they are there to protect only the appliance flex.
If an appliance needs fusing for safety reasons, it is
required to have a fuse within itself, and it isn't permitted
to rely on any plug fuse.

They don't protect people, as you would be
dead long before a fuse blew.

Depends which risk you are considering. They protect you
from a fire which might otherwise result.

Mainland European installations have relied on RCDs for many years. An
RCD protects people, not appliances, so you aren't likely to be
electrocuted thanks to a flimsy plug, although there may be a slightly
higher fire risk (or so I am told).

I won't claim a vast experience across all mainland European
installations, but I have never seen an RCD to protect people
against electrocution used in the premises wiring (except for
the occasional RCD-protected outdoor socket). RCD's are common
in mainland Europe because TT and IT installations are more
common than they are here, but those are normally 500mA RCDs
in the areas of Europe I've seen them, and they are part of
the supplier's works (like the meter is).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Anthony R. Gold wrote:
On Sun, 31 Aug 2008 01:12:27 +0100, John Rumm
wrote:

If they don't use a ring mains configuration but a radial system, such as
used in the USA, then wiring can be safely configured without plug fuses.

Whether the wiring is radial or ring makes no difference. What is
important is that fused plugs allow circuit protection at a higher
rating than would be permitted for individual appliances.

I disagree; with a radial system it is possible to protect the appliance
cord at the distribution circuit breaker. That is not possible with a ring
main.

Why not? If you protected your circuit with a 16A MCB (be it radial or
ring) then the appliance flex would be protected at the origin of the
circuit.

You also could have suggested 32A appliance cords.

Not really, ignoring the impracticability of the size of the flex
required, there is the problem that the socket and plug are not rated
for the current.

The fact that an MCB might trip does not demonstrate the system is unsafe.

No, just that the design is not really fit for purpose.

However putting a 5A fuse into the plug of a 2kW kettle in the UK does not
prove that the architecture of the wiring system is not fit for purpose.

Did anyone say it does? A 5A fuse in a 2kW appliance is an error. A 16A
MCB on a general purpose power circuit is a design choice. However it
would be a poor design choice for a circuit designed for a diverse load
pattern, that can serve 100m^2 of floor area, and is cabled to handle in
excess of 7kW of load.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
Anthony R. Gold wrote:
I am disappointed that my remark about plug fuses being needed in the UK
because of the use ring mains in the UK has turned into arguments over
whether any particular architecture is superior or unfit for purpose.

Unless a radial circuit is restricted to the current of the smallest flex
likely to be plugged into it - which would be silly - a fused plug remains
a good idea, regardless of the type of circuit.

--
*I'm already visualizing the duct tape over your mouth

Dave Plowman London SW
To e-mail, change noise into sound.

Anthony R. Gold wrote:

I am disappointed that my remark about plug fuses being needed in the UK
because of the use ring mains in the UK has turned into arguments over
whether any particular architecture is superior or unfit for purpose.

I was not arguing that one architecture is superior to another (I
believe there are pros and cons to both circuit types and one needs to
chose which to use based on circumstance). However I was questioning
your assertion that fuses are required *because* of the use of ring
circuits.

I was highlighting that the requirement for the fuse is nothing to do
with the circuit architecture. A 32A radial wired in 4mm^2 T&E would
also require fused plugs for exactly the same reasons.

The crux of the issue is that if you have a circuit capable of supplying
a current significantly in excess of the rating of the appliance flex,
then you need a overcurrent protected plug. So its not really anything
to do with the circuit being a ring or not, even if that is the most
commonly encountered 32A circuit in the UK.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In uk.d-i-y, John Rumm wrote:
The crux of the issue is that if you have a circuit capable of
supplying a current significantly in excess of the rating of the
appliance flex, then you need a overcurrent protected plug. So its not
really anything to do with the circuit being a ring or not, even if
that is the most commonly encountered 32A circuit in the UK.

I agree, but most of the world doesn't have fused plugs. So is there a
major problem with, say, those 3A flexes running to laptop power bricks,
plugged into a radial circuit limited to (say) 16A??

--
Mike Barnes

Anthony R. Gold wrote:
On Sun, 31 Aug 2008 15:38:30 +0100, "Dave Plowman (News)"
wrote:

In article ,
Anthony R. Gold wrote:
I am disappointed that my remark about plug fuses being needed in the UK
because of the use ring mains in the UK has turned into arguments over
whether any particular architecture is superior or unfit for purpose.
Unless a radial circuit is restricted to the current of the smallest flex
likely to be plugged into it - which would be silly - a fused plug remains
a good idea, regardless of the type of circuit.

If no national wiring code adopted that design how can you prove it's good?

Tony

Ergo, you can never introduce a new way of doing things because no
national code has specified that way therefore there is no way of
proving it's good. At least, that appears to be where you are with that
question. Doesn't make much sense to me.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

Anthony R. Gold wrote:
On Sun, 31 Aug 2008 15:42:14 +0100, John Rumm
wrote:

Anthony R. Gold wrote:

I am disappointed that my remark about plug fuses being needed in the UK
because of the use ring mains in the UK has turned into arguments over
whether any particular architecture is superior or unfit for purpose.
I was not arguing that one architecture is superior to another (I
believe there are pros and cons to both circuit types and one needs to
chose which to use based on circumstance). However I was questioning
your assertion that fuses are required *because* of the use of ring
circuits.

Easy to contradict - just find any examples of wiring codes that use ring
mains without fused plugs or any that use fused plugs on a radial system.

Well the second is easy, as I mentioned before, a 4.0mm^2 T&E 32A
radial, a standard circuit as described in BS7671.

Other countries don't tend to have comparable circuits since they don't
have plug fuses, and hence can't provide adequate protection for the
appliance flexes at the circuit origin.

To say that you can't find ring circuit designs that don't require plug
fuses seems to rather miss the point that the need for the fuse arises
out of the high current capacity of the circuit and not its topology.

Turn it round the other way, can you justify the need for a plug fuse
just on the basis of having parallel connection paths to the circuit
breaker? (or for that matter any other unique characteristic of a ring
circuit other than its high current delivery capacity)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

You need three adaptors
16A blue to 16 A blue, polarity reversed
16A blue to continental
16A blue to continental, polarity reversed

Surely you only need the first and second - you can use them together to
crate the third?

Mike Barnes wrote:
In uk.d-i-y, John Rumm wrote:
The crux of the issue is that if you have a circuit capable of
supplying a current significantly in excess of the rating of the
appliance flex, then you need a overcurrent protected plug. So its not
really anything to do with the circuit being a ring or not, even if
that is the most commonly encountered 32A circuit in the UK.

I agree, but most of the world doesn't have fused plugs. So is there a
major problem with, say, those 3A flexes running to laptop power bricks,
plugged into a radial circuit limited to (say) 16A??

In this case you are assuming that the internal overcurrent protection
in the PSU will protect the flex[1]. This does however leave a *small*
risk that the flex gets reused on another appliance with a higher load.

(However since the connector choice will usually limit what you can
connect the flex to anyway this is not usually a problem in real life,
unless someone gets inventive with home made adaptors - the telefunken
socket to four way socket outlet might prove interesting! ;-)

[1] This is a similar arrangement to the way a spur from a ring circuit
is protected - the protection from over current moving to the
destination end, and the protection from fault currents remaining at the
origin.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
Mike Barnes writes:
In uk.d-i-y, John Rumm wrote:
The crux of the issue is that if you have a circuit capable of
supplying a current significantly in excess of the rating of the
appliance flex, then you need a overcurrent protected plug. So its not
really anything to do with the circuit being a ring or not, even if
that is the most commonly encountered 32A circuit in the UK.

I agree, but most of the world doesn't have fused plugs. So is there a
major problem with, say, those 3A flexes running to laptop power bricks,
plugged into a radial circuit limited to (say) 16A??

They have to be short, so they can pass the fault current
required to trip a 16A breaker. In practice, this doesn't
seem to be a problem. The only effect in the UK when our
appliances became subject to EU rules in this area was that
the lengths of such flexs are now limited to 2 or 3 metres.
When using a 3A fused plug, the limit on length was much
longer than was ever likely to be encountered.

Most appliances don't have a failure mode whereby they can
overload their flex, so there isn't a risk of running 15A
continuously through a 3A flex. The flex does have to handle
a fault current though (dead short), and pass enough current
so that the 16A breaker trips before the flex overheats.
This requires the flex resistance to be low, and hence the
limit on flex lengths.

The one item which completely screws up such design
considerations is an extension cable. These are routinely
available in lengths and sizes which are not intrinsicly
safe. Even if they weren't, people would still plug them
together to contrive to make them so.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
"Anthony R. Gold" writes:

The point is that other countries could have adopted this and did not and I
doubt that is because the possibility was never considered. Of course the

All the countries which have redesigned their final circuit
arrangements since we did so post war have adopted the UK 13A plug.
I think that speaks volumes for it. (I'm less clear how many of
these routinely use radial verses rings.)

Of course, most countries are still stuck with much older designs.

entire ring system was born of post-war poverty and the copper shortage.

Ever get that feeling of deja vu?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Anthony R. Gold wrote:
On Sun, 31 Aug 2008 16:22:07 +0100, Rod wrote:

Anthony R. Gold wrote:
On Sun, 31 Aug 2008 15:38:30 +0100, "Dave Plowman (News)"
wrote:

In article ,
Anthony R. Gold wrote:
I am disappointed that my remark about plug fuses being needed in the UK
because of the use ring mains in the UK has turned into arguments over
whether any particular architecture is superior or unfit for purpose.
Unless a radial circuit is restricted to the current of the smallest flex
likely to be plugged into it - which would be silly - a fused plug remains
a good idea, regardless of the type of circuit.
If no national wiring code adopted that design how can you prove it's good?

Tony
Ergo, you can never introduce a new way of doing things because no
national code has specified that way therefore there is no way of
proving it's good. At least, that appears to be where you are with that
question. Doesn't make much sense to me.

The point is that other countries could have adopted this and did not and I
doubt that is because the possibility was never considered. Of course the
entire ring system was born of post-war poverty and the copper shortage.

Tony

Which countries have been in a position to do so? (Basically, that means
after the UK had implemented the fused plug.)

From what little I know, it appears that most countries have only
really been able to adopt an existing system wholesale. One country with
which I was a bit familiar was the UAE - where every socket seems to be
standard UK 13-amp and every plug is fused. (But I do not know what
circuitry lay behind them.)

I cannot imagine any country other than USA, Russia, China or India, or
maybe a major trading block like the EU, could now implement any
significantly different system. And those would have their work cut out
trying to do so.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

In article ,
Anthony R. Gold wrote:
Unless a radial circuit is restricted to the current of the smallest
flex likely to be plugged into it - which would be silly - a fused
plug remains a good idea, regardless of the type of circuit.

If no national wiring code adopted that design how can you prove it's
good?

You don't need to prove common sense.

--
*If PROGRESS is for advancement, what does that make CONGRESS mean?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Anthony R. Gold wrote:
Ergo, you can never introduce a new way of doing things because no
national code has specified that way therefore there is no way of
proving it's good. At least, that appears to be where you are with
that question. Doesn't make much sense to me.

The point is that other countries could have adopted this and did not

Can you name any developed country which has changed their plug and socket
design - apart from the UK?

and I doubt that is because the possibility was never considered. Of
course the entire ring system was born of post-war poverty and the
copper shortage.

That was one advantage, yes.

Are you old enough to remember the bodges that existed before final ring
circuits?

--
*Being healthy is merely the slowest possible rate at which one can die.

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Liquorice wrote:

I should hope it places a resistor between L and N and across the
current transformer. So that it actually tests what it is supposed to
be doing rather than relying on another path that might not exist.

But a resistor between L & N only simulates a load so it won't trip the RCD.
A RCD relies on an imbalance between the current in the Live wire and the
current in the Neutral wire. So the test will put a resistor between L and
Earth or between N and Earth. If you put a resistor between L & N the same
current flows in both wires so won't trip the breaker.

Trust me I work with electricity every day.

--
Malc
R1100RS old and tatty

You laugh at me because I am different
I laugh at you because you are all the same

Dave Plowman (News) wrote:
In article ,
Anthony R. Gold wrote:
Ergo, you can never introduce a new way of doing things because no
national code has specified that way therefore there is no way of
proving it's good. At least, that appears to be where you are with
that question. Doesn't make much sense to me.

The point is that other countries could have adopted this and did not

Can you name any developed country which has changed their plug and
socket design - apart from the UK?

Brazil, to a new one slightly different from a Swiss one,
Denmark, (from one that, as well as the correct one, accepted German/French
plugs but didn't connect the earth) to the French type,
Italy: from the wide-spaced 16-A one to a Shuko variant with an extra earth
in the middle, to also accept their 3-pin 6-A plugs.
Australia, from various old British types.
USA, but just added an earth to the existing type.
Republic of Ireland, from Schuko plus the odd old British type, to UK type.


and I doubt that is because the possibility was never considered. Of
course the entire ring system was born of post-war poverty and the
copper shortage.

That was one advantage, yes.

Are you old enough to remember the bodges that existed before final
ring circuits?
Yes!