Pond Electrics Question

[Will James]

Hi
I am thinking of getting one of the standard three way weather proof
switchs to control my lights/pump/water feature etc. However, on the
instructions for my Hozelock pump it states a residual current device (RCD)
must be used. I can't see any mention of a RCD being included on any of
these switches, so do I need a separate RCD and if so where would I attach
it, the external cable is currently linked to a fused switch inside the
house.

Thanks,

Will

[Roy]

All a RCD is, is a circuit breaker or fuse.......and yes it owuld be
prudent to have the hookup to a circuit breaker of the GFCI
type.....Actualy if you already have power out to your pond now, I
hope you have such a device in use.....Its russian roulette without
one around water.

On Mon, 1 Aug 2005 12:36:04 +0100, "Will James"
> wrote:

>===<>Hi
>===<> I am thinking of getting one of the standard three way weather proof
>===<>switchs to control my lights/pump/water feature etc. However, on the
>===<>instructions for my Hozelock pump it states a residual current device (RCD)
>===<>must be used. I can't see any mention of a RCD being included on any of
>===<>these switches, so do I need a separate RCD and if so where would I attach
>===<>it, the external cable is currently linked to a fused switch inside the
>===<>house.
>===<>
>===<>Thanks,
>===<>
>===<>Will
>===<>


==============================================
Put some color in your cheeks...garden naked!
"The original frugal ponder"
~~~~ }<((((o> ~~~~~~ }<{{{{o> ~~~~~~~ }<(((((o>

[Will James]

Hello Roy,
thanks for your response. We do currently have a high quality
weatherproof 2xsocket with a RCD (with a trst + reset switch) by the pond
but we are getting some pond lights and need more than 2 inputs - I can't
find any multi-switch with hardwiring (as opposed to sockets) that has a RCD
built in, so unless anyone knows of one it looks like I'll have to somehow
replace the switch which is inside the house with a socket, then attach a
plug to the wire coming from the pond, then plug that into one of the small
RCDs that will then plug into the new socket?

Will
"Roy" > wrote in message
...
> All a RCD is, is a circuit breaker or fuse.......and yes it owuld be
> prudent to have the hookup to a circuit breaker of the GFCI
> type.....Actualy if you already have power out to your pond now, I
> hope you have such a device in use.....Its russian roulette without
> one around water.
>
> On Mon, 1 Aug 2005 12:36:04 +0100, "Will James"
> > wrote:
>
> >===<>Hi
> >===<> I am thinking of getting one of the standard three way weather
proof
> >===<>switchs to control my lights/pump/water feature etc. However, on the
> >===<>instructions for my Hozelock pump it states a residual current
device (RCD)
> >===<>must be used. I can't see any mention of a RCD being included on any
of
> >===<>these switches, so do I need a separate RCD and if so where would I
attach
> >===<>it, the external cable is currently linked to a fused switch inside
the
> >===<>house.
> >===<>
> >===<>Thanks,
> >===<>
> >===<>Will
> >===<>
>
>
> ==============================================
> Put some color in your cheeks...garden naked!
> "The original frugal ponder"
> ~~~~ }<((((o> ~~~~~~ }<{{{{o> ~~~~~~~ }<(((((o>

[Hal]

On Mon, 1 Aug 2005 12:36:04 +0100, "Will James"
> wrote:

>Hi
> I am thinking of getting one of the standard three way weather proof
>switchs to control my lights/pump/water feature etc. However, on the
>instructions for my Hozelock pump it states a residual current device (RCD)
>must be used. I can't see any mention of a RCD being included on any of
>these switches, so do I need a separate RCD and if so where would I attach
>it, the external cable is currently linked to a fused switch inside the
>house.
>
http://en.wikipedia.org/wiki/Residual_current_device

Yes! Place the RCD at the pond end of the external cable and connect
everything to it. The circuit breaker inside the house won't protect
you against an energy leak, like a worn pump motor that can develop an
electrical energy leak, the RCD will.

Regards,

Hal

[Will James]

"Hal" > wrote in message
...
> On Mon, 1 Aug 2005 12:36:04 +0100, "Will James"
> > wrote:
>
> >Hi
> > I am thinking of getting one of the standard three way weather proof
> >switchs to control my lights/pump/water feature etc. However, on the
> >instructions for my Hozelock pump it states a residual current device
(RCD)
> >must be used. I can't see any mention of a RCD being included on any of
> >these switches, so do I need a separate RCD and if so where would I
attach
> >it, the external cable is currently linked to a fused switch inside the
> >house.
> >
> http://en.wikipedia.org/wiki/Residual_current_device
>
> Yes! Place the RCD at the pond end of the external cable and connect
> everything to it. The circuit breaker inside the house won't protect
> you against an energy leak, like a worn pump motor that can develop an
> electrical energy leak, the RCD will.
>
> Regards,
>
> Hal
Thanks Hal,
I'm still not certain exactly where I should put the RCD or what kind of
RCD I should get. I currently have a couple of portable RCDs that are just
things that plug into sockets inside that I plug my extension cable into for
using strimmers etc. But as these switch boxes don't have sockets what type
of RCD do I get that would fit to this switchbox?

Thanks,

Will

[Derek Broughton]

Will James wrote:

> I am thinking of getting one of the standard three way weather proof
> switchs to control my lights/pump/water feature etc. However, on the
> instructions for my Hozelock pump it states a residual current device
> (RCD) must be used. I can't see any mention of a RCD being included on any
> of these switches, so do I need a separate RCD and if so where would I
> attach it, the external cable is currently linked to a fused switch inside
> the house.

The way I did it when wiring up my pond was to place a GFI receptacle on the
(inside) wall of the house where the circuit to the pond left the house.
The electrical inspector was happy with that.
--
derek

[Rodney Pont]

On Mon, 01 Aug 2005 18:49:32 -0300, Derek Broughton wrote:

>Will James wrote:
>
>> I am thinking of getting one of the standard three way weather proof
>> switchs to control my lights/pump/water feature etc. However, on the
>> instructions for my Hozelock pump it states a residual current device
>> (RCD) must be used. I can't see any mention of a RCD being included on any
>> of these switches, so do I need a separate RCD and if so where would I
>> attach it, the external cable is currently linked to a fused switch inside
>> the house.
>
>The way I did it when wiring up my pond was to place a GFI receptacle on the
>(inside) wall of the house where the circuit to the pond left the house.
>The electrical inspector was happy with that.

That's the correct way, the complete outside circuit should/must be
protected so putting the RCD at the pond isn't any good.

--
Regards - Rodney Pont
The from address exists but is mostly dumped,
please send any emails to the address below
e-mail ngpsm4 (at) infohitsystems (dot) ltd (dot) uk

[Hal]

On Mon, 1 Aug 2005 21:35:56 +0100, "Will James"
> wrote:

> I'm still not certain exactly where I should put the RCD or what kind of
>RCD I should get. I currently have a couple of portable RCDs that are just
>things that plug into sockets inside that I plug my extension cable into for
>using strimmers etc. But as these switch boxes don't have sockets what type
>of RCD do I get that would fit to this switchbox?

Sorry, I'm not familiar with the hardware available to you. I solved
my problem using an outlet with a GFCI as the first thing on the line
servicing the pond. Everything plugged in the GFCI socket and
connected to the line beyond the GFCI is governed by the device. The
physical location of the device may be inside, or outside in weather
proof boxes, but it must be the first thing in the circuit with
everything you wish it to govern.

Regards,

Hal

[sean mckinney]

With regard to fitting an RCD to the supply to a pond,
I would fit the RCD in the house as has been suggested so that it
protects everything outside the house.

HOWEVER,

I believe the standard RCD's available in the UK as rated at 30 and 50
mA trips, I assume you are UK based since you use the term RCD and the
email address. After seeing, and being involved in, some interesting
debates on electrical safety on some of the american boards, where
earthing of the pond water directly to the ground and unearthed devices
are not uncommon, I performed a series of experiments to check the
effectivness of a 30mA RCD

http://tinyurl.com/7ez7k

http://tinyurl.com/96twm

You may have to register with either or both of those boards to see the
threads, sorry.

DO NOT attempt the experiment yourself, I had a reasonable idea of what
I was doing

The conclusion of the experiment is, that if a submerged 'break' in the
insulation of the live etc occurs some distance away from a good earth a
30mA RCD may not 'see' enough leakage current to trip and thus the water
will still be live. BTW my 30 mA RCD was and is working perfectly well,
in fact I measured the current required to trip it and that current
was, from memory, in the low to mid 20 mA range, ie below 30mA.
An american, Johns, repeated the experiment with a US spec 5mA tripping
RCD/GFI and that did trip, see the 2nd of the links above. I would
therefore suggest that you try to get a 5mA trip RCD, unfortunately I
dont know if they are available.


--
sean mckinney

[Will James]

"sean mckinney" > wrote in message
...
>
> With regard to fitting an RCD to the supply to a pond,
> I would fit the RCD in the house as has been suggested so that it
> protects everything outside the house.
>
> HOWEVER,
>
> I believe the standard RCD's available in the UK as rated at 30 and 50
> mA trips, I assume you are UK based since you use the term RCD and the
> email address. After seeing, and being involved in, some interesting
> debates on electrical safety on some of the american boards, where
> earthing of the pond water directly to the ground and unearthed devices
> are not uncommon, I performed a series of experiments to check the
> effectivness of a 30mA RCD
>
> http://tinyurl.com/7ez7k
>
> http://tinyurl.com/96twm
>
> You may have to register with either or both of those boards to see the
> threads, sorry.
>
> DO NOT attempt the experiment yourself, I had a reasonable idea of what
> I was doing
>
> The conclusion of the experiment is, that if a submerged 'break' in the
> insulation of the live etc occurs some distance away from a good earth a
> 30mA RCD may not 'see' enough leakage current to trip and thus the water
> will still be live. BTW my 30 mA RCD was and is working perfectly well,
> in fact I measured the current required to trip it and that current
> was, from memory, in the low to mid 20 mA range, ie below 30mA.
> An american, Johns, repeated the experiment with a US spec 5mA tripping
> RCD/GFI and that did trip, see the 2nd of the links above. I would
> therefore suggest that you try to get a 5mA trip RCD, unfortunately I
> dont know if they are available.
>
>
> --
> sean mckinney
Thanks for everyones replies. I am in the UK, if I understood Sean correctly
I think you are saying if I cannot get hold of a 5mA RCD, it would be better
to have an RCD with an earth as near as possible in cable length terms to
the pond as well as an RCD inside which would trip the circuit if a spade
went through the outdoor cable?

Thanks,

Will

[Rodney Pont]

On Wed, 3 Aug 2005 20:39:54 +0100, Will James wrote:

>> The conclusion of the experiment is, that if a submerged 'break' in the
>> insulation of the live etc occurs some distance away from a good earth a
>> 30mA RCD may not 'see' enough leakage current to trip and thus the water
>> will still be live. BTW my 30 mA RCD was and is working perfectly well,
>> in fact I measured the current required to trip it and that current
>> was, from memory, in the low to mid 20 mA range, ie below 30mA.
>> An american, Johns, repeated the experiment with a US spec 5mA tripping
>> RCD/GFI and that did trip, see the 2nd of the links above. I would
>> therefore suggest that you try to get a 5mA trip RCD, unfortunately I
>> dont know if they are available.
>>
>>
>> --
>> sean mckinney
>Thanks for everyones replies. I am in the UK, if I understood Sean correctly
>I think you are saying if I cannot get hold of a 5mA RCD, it would be better
>to have an RCD with an earth as near as possible in cable length terms to
>the pond as well as an RCD inside which would trip the circuit if a spade
>went through the outdoor cable?

I think what he is saying is that with a break under water the leakage
to earth was less than 30mA due to the high resistance to earth. Maybe
the pond was lined with butyl or some other insulating material. The
water would rise to 240volts but it wouldn't harm anything and if you
put your hand in the trip would fire before enough went through you to
do any harm.

You can get all sorts of trips and I'm sure B&Q will do a selection.
Most trip at 30mA but you can get them as spurs or single/dual sockets.
I don't know what the relevant BS standards that are quoted mean but
they may not necessarily be a standard for tripping. For instance all
BS1363 means is that the plug insulation will withstand 10,000 volts.

--
Regards - Rodney Pont
The from address exists but is mostly dumped,
please send any emails to the address below
e-mail ngpsm4 (at) infohitsystems (dot) ltd (dot) uk

[sean mckinney]

Will James Wrote:
> Thanks for everyones replies. I am in the UK, if I understood Sean
> correctly
> I think you are saying if I cannot get hold of a 5mA RCD, it would be
> better
> to have an RCD with an earth as near as possible in cable length terms
> to
> the pond as well as an RCD inside which would trip the circuit if a
> spade
> went through the outdoor cable?
>
> Thanks,
>
> Will
>
>[/i][/color]
Sorry but no, what I am saying is that in my opinion a 30mA RCD cant be
relied upon to make a pond safe. The problem is that the water is
resistive and as such as the distance between the source of the leakage
and whatever provides the electrical earth in the pond increases the
leakage current quickly drops below the trip value for a 30mA RCD,
salted water is probably more conductive than unsalted water so this
may not be a concern in a salted pond but I dont salt my pond.
In practical terms I assume that most UK pond devices, pumps, lights
etc, are earthed, I have yet to see an unearhed UK device, and that the
earth point is very close to any likely source of leakage, UNLESS a
cable gets nicked, so a 30mA RCD would most likely trip. However should
the fault be a cable nick etc the RCD may not trip. IMO the length of
the earth wire is irrelevant providing all connections are good.


--
sean mckinney