Hello,

I'm waiting for my on-site guide to arrive from Amazon. In the
meantime, please could you tell me the rules regarding RCDs and
bathrooms?

Does the bathroom have to have its own RCD'ed CU or can it come off
the RCD in the main CU?

How is a bathroom normally wired? I appreciate electric showers have
their own, thick, radial, but I am thinking of a 400W towel heater.
Would you run a dedicated radial to this or could it be run as an
RCD'ed spur off the upstair's ring main?

TIA
Sam

Sam coughed up some electrons that declared:

Hello,

I'm waiting for my on-site guide to arrive from Amazon. In the
meantime, please could you tell me the rules regarding RCDs and
bathrooms?


I don't have my books to hand, so I'm going to check this later, for the
17th - but, tentatively:

From memory, *all* circuits in a bathroom need RCD protection. This includes
the mains supply to any SELV transformers that supply anything in the
bathroom (even if the transformer is somewhere else, lighting, hard wired
appliances like washing machines and boilers (though there may be a caveat
if say the boiler is in a locked cupboard).

Also, no sockets within 3m of zone 1.

Does the bathroom have to have its own RCD'ed CU or can it come off
the RCD in the main CU?

No real restriction on where the RCDs (or RCBOs) are.

How is a bathroom normally wired? I appreciate electric showers have
their own, thick, radial, but I am thinking of a 400W towel heater.
Would you run a dedicated radial to this or could it be run as an
RCD'ed spur off the upstair's ring main?

Towel rail off a fused spur is OK, provided there is an RCD protecting the
circuit.

Cheers

Tim

"Sam" wrote in message
...
Hello,

I'm waiting for my on-site guide to arrive from Amazon. In the
meantime, please could you tell me the rules regarding RCDs and
bathrooms?

Does the bathroom have to have its own RCD'ed CU or can it come off
the RCD in the main CU?

How is a bathroom normally wired? I appreciate electric showers have
their own, thick, radial, but I am thinking of a 400W towel heater.
Would you run a dedicated radial to this or could it be run as an
RCD'ed spur off the upstair's ring main?

In my last house had an electric towel rail spured off ring via an RCD
located on the landing. Did modify adding a time clock to reduce electric
bill as without a timer didn't dry the towels too well as the thermostat
tended to turn it off when the central heating was on (leaving damp towels),
so you turned in up and it never turned off.

On Fri, 07 Nov 2008 12:07:58 GMT someone who may be Sam
wrote this:-

How is a bathroom normally wired? I appreciate electric showers have
their own, thick, radial, but I am thinking of a 400W towel heater.
Would you run a dedicated radial to this or could it be run as an
RCD'ed spur off the upstair's ring main?

One of the objectives of a ring final circuit is to allow a variety
of devices to be connected to it, thus achieving economy of
materials without disconnection of the circuit due to overloading.
Heavy and steady loads should not be connected directly to one, such
as large heaters, but a 400W towel rail is the sort of small load
which is ideal to connect to the ring.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Sam wrote:

Does the bathroom have to have its own RCD'ed CU or can it come off
the RCD in the main CU?

The same RCD protection as elsewhere is fine, so long as it is by a =30
mA trip RCD.

How is a bathroom normally wired? I appreciate electric showers have

There was a point where it appeared that bathrooms were going to pose a
special requirement wrt to RCD protection, in that they needed it for
*all* circuits entering the room including lighting etc. However another
amendment to what finally became the 17th edition introduced a
requirement for additional protection of buried cables. That to all
intents and purposes makes it simpler to provide RCD protection
(suitably partitioned to maintain discrimination) for all circuits in
the house anyway - so the bathroom gets a free ride.

their own, thick, radial, but I am thinking of a 400W towel heater.
Would you run a dedicated radial to this or could it be run as an
RCD'ed spur off the upstair's ring main?

A 400W load is fine on a ring circuit.



--
Cheers,

John.

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

Tim S wrote:
Sam coughed up some electrons that declared:

Hello,

I'm waiting for my on-site guide to arrive from Amazon. In the
meantime, please could you tell me the rules regarding RCDs and
bathrooms?


I don't have my books to hand, so I'm going to check this later, for the
17th - but, tentatively:

From memory, *all* circuits in a bathroom need RCD protection. This includes
the mains supply to any SELV transformers that supply anything in the
bathroom (even if the transformer is somewhere else, lighting, hard wired
appliances like washing machines and boilers (though there may be a caveat
if say the boiler is in a locked cupboard).


No, I am fairly sure that none of that is needed. 13A sockets are
(almost)not allowed, and the rest is either well out of reach, or double
insulated.


Also, no sockets within 3m of zone 1.


Yup. Which n most bathrooms means 'no sockets'

Does the bathroom have to have its own RCD'ed CU or can it come off
the RCD in the main CU?

No real restriction on where the RCDs (or RCBOs) are.

How is a bathroom normally wired? I appreciate electric showers have
their own, thick, radial, but I am thinking of a 400W towel heater.
Would you run a dedicated radial to this or could it be run as an
RCD'ed spur off the upstair's ring main?

Towel rail off a fused spur is OK, provided there is an RCD protecting the
circuit.

Ah, in that case you may be right. Everything else normally runs of a
lighting circuit,

Cheers

Tim

On Fri, 7 Nov 2008 16:10:27 -0000, "Ian_m"
wrote:

In my last house had an electric towel rail spured off ring via an RCD
located on the landing. Did modify adding a time clock to reduce electric
bill as without a timer didn't dry the towels too well as the thermostat
tended to turn it off when the central heating was on (leaving damp towels),
so you turned in up and it never turned off.

I'm puzzled by the remarks about the thermostat. Did you have a
thermostat in the bathroom or was there a thermostat in the element?
Mine is just a plain element; the thermostatic ones seem to be £80
plus, but I thought they would switch off at scalding temperatures,
rather than room temperatures?

Did you have an external thermostat; if so are they allowed in zone 3?
I suppose a wireless one would be allowed but does it agree with the
humidity?

I did wonder about using a CH controller to act as a time switch; it
would also give a one hour boost option that you would not get with a
plain time switch. A one hour boost would be useful because like you
say, you don't have to remember to turn them off. However I wasn't
sure that a CH controller would be sufficiently rated? I know 400W is
barely a couple of amps, but is there a spike when it switches on or
off?

On Fri, 07 Nov 2008 17:23:37 +0000, David Hansen
wrote:

One of the objectives of a ring final circuit is to allow a variety
of devices to be connected to it, thus achieving economy of
materials without disconnection of the circuit due to overloading.
Heavy and steady loads should not be connected directly to one, such
as large heaters, but a 400W towel rail is the sort of small load
which is ideal to connect to the ring.

I wouldn't have asked had it been anywhere else, but I wasn't sure
whether being the bathroom it required its own circuit.

Thanks for all the replies.

On Fri, 07 Nov 2008 12:50:57 +0000, Tim S wrote:

Also, no sockets within 3m of zone 1.

That's interesting. I was going to ask what if the socket falls within
zone 3 but also within 3m metres of zone 1 but I went online to search
for a diagram of the zones to check whether this would be possible and
I have learned that there is no zone three anymore. Why has this been
lost? Is it only sockets that are forbidden because I will obviously
need a FCU to connect the towel rail to. I wasn't sure how waterproof
the fuse was.

Thanks for all the replies. It is reassuring to know it can be
connected to the RCD in the consumer unit. This has the disadvantage
of taking the other circuits out of there is a problem, but hopefully
false alarms on the bathroom will be non-existent.

Thanks again.

On Fri, 7 Nov 2008 16:10:27 -0000, "Ian_m"
wrote:

In my last house had an electric towel rail spured off ring via an RCD
located on the landing.

I forgot to ask: presumably there was no RCD at the CU if you had an
RCD'ed spur? I once used one of those plug-in RCD things, not
realising that it was plugged into an RCD'd ring. When I pressed the
test button on the unit it caused both the RCD in the plug-in part to
trip but also that in the CU, so I presume there is no advantage to
chaining RCDs; it's not as thought the first one trips before the
second in the chain.

Thanks again.

The Natural Philosopher coughed up some electrons that declared:

Tim S wrote:
Sam coughed up some electrons that declared:

Hello,

I'm waiting for my on-site guide to arrive from Amazon. In the
meantime, please could you tell me the rules regarding RCDs and
bathrooms?


I don't have my books to hand, so I'm going to check this later, for the
17th - but, tentatively:

From memory, *all* circuits in a bathroom need RCD protection. This
includes the mains supply to any SELV transformers that supply anything
in the bathroom (even if the transformer is somewhere else, lighting,
hard wired appliances like washing machines and boilers (though there may
be a caveat if say the boiler is in a locked cupboard).


No, I am fairly sure that none of that is needed. 13A sockets are
(almost)not allowed, and the rest is either well out of reach, or double
insulated.


I'm afraid that it *is* the case that *all* circuits in a location
containing a bath or or shower. Double insulated and out of reach aren't
relevant under the 17th

Now I've got me books to hand:

Regulation 701.411.3.3:

"Additional protection shall be provided for all circuits of the location,
by use of one or more RCDs having the characteristics specified in
Regulation 415.1.1"

415.1.1: 30mA sensitivity, 40ms @ 5x trip-current (ie a "standard" RCD)

The only socket allowed within 3m of Zone 1 is of course the isolated-shaver
shocket, and even the primary winding supply is required to be RCD
protected.

It appears that all of this now applied to bedrooms with en-suites
(specifically with a shower cubical, unless, I suppose, the shower is in
it's own room entirely.).

Then again, as someone said earlier, unless you get clever with your
cabling, everything needs a 30mA RCD anyway now to comply with the new
regs.

Cheers

Tim

Sam coughed up some electrons that declared:

On Fri, 7 Nov 2008 16:10:27 -0000, "Ian_m"
wrote:

In my last house had an electric towel rail spured off ring via an RCD
located on the landing.

I forgot to ask: presumably there was no RCD at the CU if you had an
RCD'ed spur? I once used one of those plug-in RCD things, not
realising that it was plugged into an RCD'd ring. When I pressed the
test button on the unit it caused both the RCD in the plug-in part to
trip but also that in the CU, so I presume there is no advantage to
chaining RCDs; it's not as thought the first one trips before the
second in the chain.


That's correct.

The only common (domestic) case where you do chain RCDs is on a TT (earth
rod) installation.

There, the usual solution is a 100mA (or 300mA) Type S (time delayed) RCD
protecting everything, and the usual 30mA RCDs everywhere else.

The time delay engineered into the Type S is specifically set so that a
normal RCD will open the circuit first.

Cheers

Tim

Sam coughed up some electrons that declared:

On Fri, 07 Nov 2008 12:50:57 +0000, Tim S wrote:

Also, no sockets within 3m of zone 1.

That's interesting. I was going to ask what if the socket falls within
zone 3 but also within 3m metres of zone 1 but I went online to search
for a diagram of the zones to check whether this would be possible and
I have learned that there is no zone three anymore.

That's right.

Why has this been
lost?

Don;t know - probably something to do with harmonising the regs with
european conterparts (though the german VDE100 regs *do* allow a shuko
socket with suitable RCD protection in a bathroom).

Is it only sockets that are forbidden because I will obviously
need a FCU to connect the towel rail to. I wasn't sure how waterproof
the fuse was.

FCU is fine. The theory is more to do with some daft sod pluging their hair
dryer in and being able to sit in the bath using it (3m is based on the
longest length of flex likely to be fitted to an appliance).

As far as siting, use common sense and certainly avoid areas likely to e hit
by direct spray.

One solution sometimes used is to put only a flex connector plate in the
bathroom, then put the fused-switch behind it on the other side of the
wall.


Thanks for all the replies. It is reassuring to know it can be
connected to the RCD in the consumer unit. This has the disadvantage
of taking the other circuits out of there is a problem, but hopefully
false alarms on the bathroom will be non-existent.

Cheers

Tim

Tim S wrote:
Sam coughed up some electrons that declared:

On Fri, 07 Nov 2008 12:50:57 +0000, Tim S wrote:

Also, no sockets within 3m of zone 1.
That's interesting. I was going to ask what if the socket falls within
zone 3 but also within 3m metres of zone 1 but I went online to search
for a diagram of the zones to check whether this would be possible and
I have learned that there is no zone three anymore.

That's right.

Why has this been
lost?

Don;t know - probably something to do with harmonising the regs with
european conterparts (though the german VDE100 regs *do* allow a shuko
socket with suitable RCD protection in a bathroom).

I think it is because zone 3 as a concept (ordinary appliances allowed,
but must be protected by a = 30mA trip RCD) has now been assumed as the
standard for outside of the zones. Hence there is no longer any
difference between zone 3 and outside, so you may as well ditch it.

Is it only sockets that are forbidden because I will obviously
need a FCU to connect the towel rail to. I wasn't sure how waterproof
the fuse was.

FCU is fine. The theory is more to do with some daft sod pluging their hair
dryer in and being able to sit in the bath using it (3m is based on the
longest length of flex likely to be fitted to an appliance).

Lets hope they were not planning to sit in the bath and clean the grout
with their Fein multimaster then (4m ish lead) ;-)


As far as siting, use common sense and certainly avoid areas likely to e hit
by direct spray.

One solution sometimes used is to put only a flex connector plate in the
bathroom, then put the fused-switch behind it on the other side of the
wall.

The general requirement that accessories should be chosen so as to be
appropriate for the situation still applies. So as you said, use common
sense and you will be fine.


--
Cheers,

John.

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

Tim S wrote:
The Natural Philosopher coughed up some electrons that declared:

Tim S wrote:
Sam coughed up some electrons that declared:

Hello,

I'm waiting for my on-site guide to arrive from Amazon. In the
meantime, please could you tell me the rules regarding RCDs and
bathrooms?

I don't have my books to hand, so I'm going to check this later, for the
17th - but, tentatively:

From memory, *all* circuits in a bathroom need RCD protection. This
includes the mains supply to any SELV transformers that supply anything
in the bathroom (even if the transformer is somewhere else, lighting,
hard wired appliances like washing machines and boilers (though there may
be a caveat if say the boiler is in a locked cupboard).

No, I am fairly sure that none of that is needed. 13A sockets are
(almost)not allowed, and the rest is either well out of reach, or double
insulated.


I'm afraid that it *is* the case that *all* circuits in a location
containing a bath or or shower. Double insulated and out of reach aren't
relevant under the 17th

Now I've got me books to hand:

Regulation 701.411.3.3:

"Additional protection shall be provided for all circuits of the location,
by use of one or more RCDs having the characteristics specified in
Regulation 415.1.1"

415.1.1: 30mA sensitivity, 40ms @ 5x trip-current (ie a "standard" RCD)

The only socket allowed within 3m of Zone 1 is of course the isolated-shaver
shocket, and even the primary winding supply is required to be RCD
protected.

It appears that all of this now applied to bedrooms with en-suites
(specifically with a shower cubical, unless, I suppose, the shower is in
it's own room entirely.).

Then again, as someone said earlier, unless you get clever with your
cabling, everything needs a 30mA RCD anyway now to comply with the new
regs.


When di thise regs come in? fairly sure not mentioned in 2000 regs..

Cheers

Tim

On Sat, 08 Nov 2008 07:42:54 +0000 someone who may be The Natural
Philosopher wrote this:-

When di thise regs come in? fairly sure not mentioned in 2000 regs..

1/7/08, from when all installations must comply with the 17th
Edition.

There was an amendment to the 16th Edition in April 2000 to do with
bathrooms, but the 16th Edition dates back to 1991 (though with
various amendments after that date).


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Fri, 07 Nov 2008 22:11:04 GMT someone who may be Sam
wrote this:-

Is it only sockets that are forbidden

It depends on the voltage and distance from bath/shower. Hopefully
your book has arrived now and you can read the details.

because I will obviously
need a FCU to connect the towel rail to. I wasn't sure how waterproof
the fuse was.

People using the bathroom are unlikely to try and do something with
the fuse, which is tucked away in the connection unit. Fused
connection units pose no greater risk than a cord outlet. What is
more likely to cause danger is operating a switch, which is why
there are regulations about where they can be placed.

Obviously a fused connection unit should not be placed in or
directly above a bath/shower (other than at high level, but many
bathrooms don't have the height), but other places are generally
fine.

There are several ways to wire a towel rail in a bathroom. A non-
exhaustive list is:

1) switched fused connection unit. The switch needs to be far enough
from the bath/shower.

2) switch outside and fused connection unit inside.

3) switched fused connection unit outside and cord outlet inside.

4) pull cord switch inside and fused connection unit by rail.

Neon indicators are useful on some/all equipment.




--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

The Natural Philosopher coughed up some electrons that declared:


When di thise regs come in? fairly sure not mentioned in 2000 regs..


Early this year, mandatory for new circuits 1/7/2008 - officially the
crossover period of using either 16th or 17th has passed.

Ironically, it took the IET until September to get the updated On Site guide
out.

Cheers

Tim

On Sat, 08 Nov 2008 10:52:17 +0000 someone who may be Owain
wrote this:-

David Hansen wrote:
When di thise regs come in?
1/7/08, from when all

insert *new*

installations must comply with the 17th
Edition.

Indeed. My mistake.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Fri, 07 Nov 2008 23:58:12 +0000, Tim S wrote:

FCU is fine. The theory is more to do with some daft sod pluging their hair
dryer in and being able to sit in the bath using it (3m is based on the
longest length of flex likely to be fitted to an appliance).

As far as siting, use common sense and certainly avoid areas likely to e hit
by direct spray.

One solution sometimes used is to put only a flex connector plate in the
bathroom, then put the fused-switch behind it on the other side of the
wall.


Thanks. I was going to put a switch in the airing cupboard, so no
chance of wet fingers touching it. In the bathroom I was going to use
a fused spur (with no switch) but just wasn't sure if the little
"flap" over the fuse was a problem with regard to water ingress, but
like you say, it's going to be sensibly away from the shower head so
it should be fine. If the switch is fused then I could, like you say,
just use a connector plate in the bathroom to be doubly sure. I would
quite like something with a neon though, so that I remember to turn
them off!

Thanks again.

On Sat, 08 Nov 2008 09:21:16 +0000, David Hansen
wrote:

Hopefully your book has arrived now and you can read the details.

No, I opted for super saver delivery so it's not here yet, but will be
any day soon.

People using the bathroom are unlikely to try and do something with
the fuse, which is tucked away in the connection unit. Fused
connection units pose no greater risk than a cord outlet.

That's what I wanted to hear, thanks.

2) switch outside and fused connection unit inside.

This is exactly what I have done.

Thanks again.

On Wed, 12 Nov 2008 09:36:47 GMT someone who may be Sam
wrote this:-

If the switch is fused then I could, like you say,
just use a connector plate in the bathroom to be doubly sure. I would
quite like something with a neon though, so that I remember to turn
them off!

I have never found a cord outlet with a neon, if anyone has please
let me know. All I have found is fused connection units with neons,
like http://www.tlc-direct.co.uk/Products/MKK0377.html and the
Crabtree equivalent.

A neon on the switch can also be useful, especially if it is outside
the bathroom.




--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"Sam" wrote in message
...
On Fri, 7 Nov 2008 16:10:27 -0000, "Ian_m"
wrote:

In my last house had an electric towel rail spured off ring via an RCD
located on the landing. Did modify adding a time clock to reduce electric
bill as without a timer didn't dry the towels too well as the thermostat
tended to turn it off when the central heating was on (leaving damp
towels),
so you turned in up and it never turned off.

I'm puzzled by the remarks about the thermostat. Did you have a
thermostat in the bathroom or was there a thermostat in the element?
Mine is just a plain element; the thermostatic ones seem to be £80
plus, but I thought they would switch off at scalding temperatures,
rather than room temperatures?

Did you have an external thermostat; if so are they allowed in zone 3?
I suppose a wireless one would be allowed but does it agree with the
humidity?

I did wonder about using a CH controller to act as a time switch; it
would also give a one hour boost option that you would not get with a
plain time switch. A one hour boost would be useful because like you
say, you don't have to remember to turn them off. However I wasn't
sure that a CH controller would be sufficiently rated? I know 400W is
barely a couple of amps, but is there a spike when it switches on or
off?

The thermostat was built in to the towel rail. Wasn't cheap £120 odd, but I
wanted one with a thermostat which in hind sight might not have been a too
great idea, but then in the summer didn't come on and towels dried OK, so
maybe worth it.

The house had a fused consumer unit (no RCD's) so an RCD fro bathroom was a
must.

You can't really use a CH timer as they are only rated typically 2A for
boiler and pump. I used a 24hour/7 day immersion heater timer rated at 13A.

David Hansen wrote:

I have never found a cord outlet with a neon, if anyone has please
let me know.

That's easily made though using two gridswitch modules.

--
Andy

On Wed, 12 Nov 2008 23:29:24 +0000 someone who may be Andy Wade
wrote this:-

I have never found a cord outlet with a neon, if anyone has please
let me know.

That's easily made though using two gridswitch modules.

Thanks. I have never seen a cord outlet module advertised, but I see
from http://www.mkelectric.co.uk/PDF/technical/GRID_PLUS_prod.pdf
that there is one.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54