Re: Transformers + electric razors

In article <(E-Mail Removed)>,
"G.Vasilev" <(E-Mail Removed)> writes:
>
> "Harrison Bored" wrote:
>>I have successfully used it off a normal mains socket (via a simple 3-pin
>>to 2-pin adapter) with no transformer.
>
> You are risky man. It would be better if you restore an isolating
> transformer. It is your safety.

The isolating transformer is part of the fixed socket outlet in UK
bathrooms, not part of the shaver. It is only required when using
the shaver in a wet room (containing a shower or bath). There's
nothing stopping you fitting an isolating socket anywhere else if
you want to (and sometimes people do), but normally regular non-
isolating shaver sockets are used in rooms which don't contain a
bath or shower.

--
Andrew Gabriel

Andrew Gabriel wrote:

>
> The isolating transformer is part of the fixed socket outlet in UK
> bathrooms, not part of the shaver. It is only required when using
> the shaver in a wet room (containing a shower or bath). There's
> nothing stopping you fitting an isolating socket anywhere else if
> you want to (and sometimes people do), but normally regular non-
> isolating shaver sockets are used in rooms which don't contain a
> bath or shower.
>

Interesting what different countries use to solve the same problem.
What is the rating of the transformer?
Locally fused?
Recessed in wall?
What if you want to plug in a heater (high Watt) in bathroom?

As you probably know, the US-NEC uses GFCIs (ground fault circuit
interrupters) that trip at 5 mA ground fault currents for safety in
bathrooms, kitchens, .... Doesn't the UK have a similar device?

(Hate to pick on you, but you post such great answers. Thanks.)

Bud--

In article <8c63a$42ea4e29$4304c852$(E-Mail Removed)>,
Bud <(E-Mail Removed)> writes:
> Interesting what different countries use to solve the same problem.
> What is the rating of the transformer?
> Locally fused?

The socket has to be limited to something like 30W (I can't
remember what the exact figure is). A slow acting self-
resetting thermal trip is integral with the transformer.
The socket is supposed to be used only for electric shavers,
toothbrushes, etc.

In addition to the 240V socket, there's usually a 120V
2-prong US socket included for visitors. Since there's a
transformer in there anyway, providing a 120V outlet too
adds nothing to the cost. The shutters on the sockets also
operate a switch which disconnects the transformer primary
when there's nothing plugged in, and provide an interlock
to prevent both the 120V and 240V sockets being used
together (or sometimes that's done by having the two sockets
partially overlap and sharing one of the prong holes).

> Recessed in wall?

Normally yes. They fit in our standard double width patress
modules, although they require the deepest size box.

> What if you want to plug in a heater (high Watt) in bathroom?

Strictly forbidden. It's not allowed to have sockets for
portable appliances in bathrooms (except for the shaver socket).
You can have a fixed electric heater in the bathroom, providing
it was designed for the purpose -- that's quite common.

> As you probably know, the US-NEC uses GFCIs (ground fault circuit
> interrupters) that trip at 5 mA ground fault currents for safety in
> bathrooms, kitchens, .... Doesn't the UK have a similar device?

We do, but they aren't acceptable in wet rooms. I think there's
a philosophy difference in that GFI's can be added to a circuit
to improve safety in the UK, but are never allowed to be relied
upon as the primary safety device because they don't fail-safe.
The use of isolating transformers in bathrooms goes back before
GFI's in any case.

GFIs are required for any sockets which might be used to supply
portable appliances outdoors (even if the socket isn't outdoors).
It's more common to have the GFI in the panel rather than in the
socket, although socket based ones are available. One thing you
have which we don't is that your GFI sockets can protect further
downstream sockets (at least in some cases) -- ours never do
that.

> (Hate to pick on you, but you post such great answers. Thanks.)

I don't mind at all.

--
Andrew Gabriel

In article <(E-Mail Removed)>,
phil-news-(E-Mail Removed) writes:
>
> Nice feature. Maybe I should import some for my own use in the USA.
> Our 60 Hz should be OK on the transformer. I'm not going to worry
> about the NEC 210.6(A)(2) violation since it would be just for visitors.

MK (one of the higher quality brands in the UK) do actually
make these with 120V mains input, presumably intended for
export somewhere.

--
Andrew Gabriel

In article <42ea7a6c$0$38039$(E-Mail Removed)>,
(E-Mail Removed) (Andrew Gabriel) writes:
>
> MK (one of the higher quality brands in the UK) do actually
> make these with 120V mains input, presumably intended for
> export somewhere.

Here's a link to the 120V version (part number K706)...
http://www.mkelectric.co.uk/products...3&rangeid=1030

It's also available in a number of other finishes
(search for part number K24710 on their homepage,
although they seem to have copied the description
for the 240V versions and not changed the voltage).

--
Andrew Gabriel

----------------------------
"Andrew Gabriel" <(E-Mail Removed)> wrote in message
news:42ea6045$0$38039$(E-Mail Removed).. .
> In article <8c63a$42ea4e29$4304c852$(E-Mail Removed)>,
> Bud <(E-Mail Removed)> writes:
>> Interesting what different countries use to solve the same problem.
>> What is the rating of the transformer?
>> Locally fused?
>
> The socket has to be limited to something like 30W (I can't
> remember what the exact figure is). A slow acting self-
> resetting thermal trip is integral with the transformer.
> The socket is supposed to be used only for electric shavers,
> toothbrushes, etc.
>
> In addition to the 240V socket, there's usually a 120V
> 2-prong US socket included for visitors. Since there's a
> transformer in there anyway, providing a 120V outlet too
> adds nothing to the cost. The shutters on the sockets also
> operate a switch which disconnects the transformer primary
> when there's nothing plugged in, and provide an interlock
> to prevent both the 120V and 240V sockets being used
> together (or sometimes that's done by having the two sockets
> partially overlap and sharing one of the prong holes).
>
>> Recessed in wall?
>
> Normally yes. They fit in our standard double width patress
> modules, although they require the deepest size box.
>
>> What if you want to plug in a heater (high Watt) in bathroom?
>
> Strictly forbidden. It's not allowed to have sockets for
> portable appliances in bathrooms (except for the shaver socket).
> You can have a fixed electric heater in the bathroom, providing
> it was designed for the purpose -- that's quite common.
>
>> As you probably know, the US-NEC uses GFCIs (ground fault circuit
>> interrupters) that trip at 5 mA ground fault currents for safety in
>> bathrooms, kitchens, .... Doesn't the UK have a similar device?
>
> We do, but they aren't acceptable in wet rooms. I think there's
> a philosophy difference in that GFI's can be added to a circuit
> to improve safety in the UK, but are never allowed to be relied
> upon as the primary safety device because they don't fail-safe.
> The use of isolating transformers in bathrooms goes back before
> GFI's in any case.
>
> GFIs are required for any sockets which might be used to supply
> portable appliances outdoors (even if the socket isn't outdoors).
> It's more common to have the GFI in the panel rather than in the
> socket, although socket based ones are available. One thing you
> have which we don't is that your GFI sockets can protect further
> downstream sockets (at least in some cases) -- ours never do
> that.
>
>> (Hate to pick on you, but you post such great answers. Thanks.)
>
> I don't mind at all.
>
> --
> Andrew Gabriel
---------------
I think that you have brought up an important point here. UK systems tend to
be much more heavily designed than North American ones with regard to
safety, possibly because of the use of 240V vs 120. Compare the construction
of a UK outlet, switch or lamp socket to a typical North American design. If
they were outhouses, the UK ones would be made of brick.

Differences in design philosophy - possibly less emphasis on the bottom line
and more on safety. Overkill - maybe, maybe not. You can make something
foolproof but not damnfool proof.
This used to extend to panels as well. The story is that Square D tried to
start up in the UK, without success, until they resurrected old designs
(cast iron, 47 bolts to hold the cover on, etc)

--

Don Kelly @shawcross.ca
remove the X to answer

Andrew Gabriel wrote:
> In article <(E-Mail Removed)>,
> phil-news-(E-Mail Removed) writes:
>
>>Nice feature. Maybe I should import some for my own use in the USA.
>>Our 60 Hz should be OK on the transformer. I'm not going to worry
>>about the NEC 210.6(A)(2) violation since it would be just for visitors.
>
>
> MK (one of the higher quality brands in the UK) do actually
> make these with 120V mains input, presumably intended for
> export somewhere.
>

How about Phil's other question - hand held hair driers. In the US they
are even common in motels.

And what is and isn't mains.

Know of any wiring-practices web sites. This and the other recent thread
are really interesting.

Bud--