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Default Rewiring garden pond pump?

I have an old pump (Lotus "Little Gem") which is still working fine (so
am loath to throw it away) but the cable is becoming very degraded: the
outer rubber cover is cracking away in several places. As far as I can
see the cable just disappears into a lump of resin(?) in the body of the
pump. Any thoughts about digging this out and replacing it (with
silicone?) -- or am I really onto a loser here?

Douglas de Lacey
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Default Rewiring garden pond pump?

On Mon, 07 Aug 2006 13:54:03 +0100 someone who may be Douglas de
Lacey wrote this:-

I have an old pump (Lotus "Little Gem") which is still working fine (so
am loath to throw it away) but the cable is becoming very degraded: the
outer rubber cover is cracking away in several places. As far as I can
see the cable just disappears into a lump of resin(?) in the body of the
pump.


Correct.

Any thoughts about digging this out and replacing it (with
silicone?) -- or am I really onto a loser here?


Throw it in the bin. Replace with another pump.

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.


--
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
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Default Rewiring garden pond pump?

David Hansen wrote:
On Mon, 07 Aug 2006 13:54:03 +0100 someone who may be Douglas de
Lacey wrote this:-

I have an old pump (Lotus "Little Gem") which is still working fine (so
am loath to throw it away) but the cable is becoming very degraded: the
outer rubber cover is cracking away in several places. As far as I can
see the cable just disappears into a lump of resin(?) in the body of the
pump.


Correct.

Any thoughts about digging this out and replacing it (with
silicone?) -- or am I really onto a loser here?


Throw it in the bin. Replace with another pump.

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.

How is anyone going to get killed (or even injured) by it? One's life
doesn't depend on the operation of a pond pump usually.

--
Chris Green
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Default Rewiring garden pond pump?

wrote in message
...

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.

How is anyone going to get killed (or even injured) by it? One's life
doesn't depend on the operation of a pond pump usually.


The pond pumps I've seen have mains cables going underwater. Seems like they
rely very much on maintaining the insulation and seals. Replacing the cable
will inevitably disturb these, and if you do get it wrong, then it's not the
operation of the pump which you're worried about, it's the elecric water
feature you now have.

clive

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Default Rewiring garden pond pump?


"Clive George" wrote in message
...
wrote in message
...

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.

How is anyone going to get killed (or even injured) by it? One's life
doesn't depend on the operation of a pond pump usually.


The pond pumps I've seen have mains cables going underwater. Seems like
they rely very much on maintaining the insulation and seals. Replacing the
cable will inevitably disturb these, and if you do get it wrong, then it's
not the operation of the pump which you're worried about, it's the elecric
water feature you now have.


You would have to repace only the cable outside the water and weatherproof
the splice in some way. Less effort to get a new pump TBH.




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Default Rewiring garden pond pump?

Douglas de Lacey wrote:

I have an old pump (Lotus "Little Gem") which is still working fine (so
am loath to throw it away) but the cable is becoming very degraded: the
outer rubber cover is cracking away in several places. As far as I can
see the cable just disappears into a lump of resin(?) in the body of the
pump. Any thoughts about digging this out and replacing it (with
silicone?) -- or am I really onto a loser here?

Douglas de Lacey


Replacement is the logical option. If for reasons unknown youre
determined to use it for another 20 years, theres always...

a) running it off isolation transformer and rcd
b) coat the cable with a mixture of silicone gloop and plastic fibres
c) or fit a new cable and epoxy waterproof the connection
d) fit earthed gauze round the lead and add rcd
e) dangle the pump just above the water so the inlet just touches the
surface but the cable doesnt

and various other equally unlikely options.


NT

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Default Rewiring garden pond pump?

Douglas de Lacey wrote:

I have an old pump (Lotus "Little Gem") which is still working fine (so
am loath to throw it away) but the cable is becoming very degraded: the
outer rubber cover is cracking away in several places. As far as I can
see the cable just disappears into a lump of resin(?) in the body of the
pump. Any thoughts about digging this out and replacing it (with
silicone?) -- or am I really onto a loser here?

Douglas de Lacey


Replacement is the logical option. If for reasons unknown youre
determined to use it for another 20 years, theres always...

a) running it off isolation transformer and rcd
b) coat the cable with a mixture of silicone gloop and plastic fibres
c) or fit a new cable and epoxy waterproof the connection
d) fit earthed gauze round the lead and add rcd
e) dangle the pump just above the water so the inlet just touches the
surface but the cable doesnt
f) fit deioniser to water feature

and various other equally unlikely options.


NT

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Default Rewiring garden pond pump?

steeler wrote:
"Clive George" wrote in message
...

wrote in message
.. .

[And David Hansen was the first quoted author]

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.


Nononono! It's for the sake of d-i-y!



How is anyone going to get killed (or even injured) by it? One's life
doesn't depend on the operation of a pond pump usually.


[David again:]

That should be fairly obvious. If they are in contact with the water
when the electricity finally escapes from the cable then they might
be killed.


I admit I was puzzled too; you mean "when the bodge funally breaks
down", right? I do have an RCD on the circuit; would that not
immediately trip? In which case only the fish are likely to be in any
danger.


The pond pumps I've seen have mains cables going underwater. Seems like
they rely very much on maintaining the insulation and seals. Replacing the
cable will inevitably disturb these, and if you do get it wrong, then it's
not the operation of the pump which you're worried about, it's the elecric
water feature you now have.



You would have to repace only the cable outside the water and weatherproof
the splice in some way. Less effort to get a new pump TBH.


No, Clive is right, the mains cable goes right into the pump, and has
degraded along the whole of the underwater length.

then added:

Replacement is the logical option. If for reasons unknown youre
determined to use it for another 20 years, theres always...


Hey, it's barely ten years old so far:-)

a) running it off isolation transformer and rcd
b) coat the cable with a mixture of silicone gloop and plastic fibres
c) or fit a new cable and epoxy waterproof the connection


That's more-or-less what I thought of

d) fit earthed gauze round the lead and add rcd
e) dangle the pump just above the water so the inlet just touches the
surface but the cable doesnt


Ooh, yes that could be fun!

and various other equally unlikely options.


Yes, I get the impression that "unlikely" is the key term. Anyone want a
*free* (but useless) pond pump?
(But I would like to know whether the RCD might fail to function
immediately the electrons begin to escape. What's the resistivity of
pond-water?)

Thanks, all, for your comments.

Douglas de Lacey
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On Tue, 08 Aug 2006 08:10:45 +0100 someone who may be Douglas de
Lacey wrote this:-

I admit I was puzzled too; you mean "when the bodge funally breaks
down",


When the existing cable breaks down.

I do have an RCD on the circuit; would that not
immediately trip?


That depends on the fault. It should do, but like any mechanical
device it may not operate properly. There are also electrical faults
that such devices don't detect. As a result relying on one to save
one's life is foolish. Far better to avoid the possibility, by
getting a new pump with a new cable.




--
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


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Douglas de Lacey wrote:

.. What's the resistivity of
pond-water?)


There's a fair number of 'impurities' abour so I imagine it is fairly
low.

My rather complex pond system has a number of points where there is
seepage loss and I installed an automatic 'topper-up' - initially the
sensor was two bits of stainless steel with dc passing through them -
two reasons lead me to work out a very low voltge / high impedance ac
system. One was the plating effect of what looked like lime on one
electrode, the other was, that although I was only using a few volts,
and possibly because it wasn't an isolated supply, it killed frogs !!

Rob

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Clive George wrote:
wrote in message
...

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.

How is anyone going to get killed (or even injured) by it? One's life
doesn't depend on the operation of a pond pump usually.


The pond pumps I've seen have mains cables going underwater. Seems like they
rely very much on maintaining the insulation and seals. Replacing the cable
will inevitably disturb these, and if you do get it wrong, then it's not the
operation of the pump which you're worried about, it's the elecric water
feature you now have.

That still doesn't explain how I (or anyone else) gets killed by it,
how does the 'electric water' get to you?

--
Chris Green
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David Hansen wrote:
On 07 Aug 2006 15:46:21 GMT someone who may be
wrote this:-

How is anyone going to get killed (or even injured) by it?


That should be fairly obvious. If they are in contact with the water
when the electricity finally escapes from the cable then they might
be killed.


--
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


In which case surely the RCD would trip. Seeing the minute amounts of
condensation that cause my RCD to trip I have absolute confidence that
water ingress into a pump would give the RCD no problems with
detection.
Having said that I wish I could more than ten years out of a
submersible pump. I have just had to chuck a 3000 gallon per hour pump
away that tripped the RCD due to very slight water ingress through a
worn cable. The pump ran quite happliy on an unprotected circuit. This
was a £200 pump. It was repairable but coming close to £200 to repair
it was it worth it. It was 10 years old so time for the dump.
If the RCD were to go while on holiday the ruined contents of your
freezer are more than the replacement cost of the pump.

Kevin

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wrote in message
...
Clive George wrote:
wrote in message
...

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.

How is anyone going to get killed (or even injured) by it? One's life
doesn't depend on the operation of a pond pump usually.


The pond pumps I've seen have mains cables going underwater. Seems like
they
rely very much on maintaining the insulation and seals. Replacing the
cable
will inevitably disturb these, and if you do get it wrong, then it's not
the
operation of the pump which you're worried about, it's the elecric water
feature you now have.

That still doesn't explain how I (or anyone else) gets killed by it,
how does the 'electric water' get to you?


One is standing in the garden and dangles ones fingers in the pretty
waterfall. Or similar.

(isn't that _really_ obvious?)

clive

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Clive George wrote:
wrote in message
...
Clive George wrote:
wrote in message
...

I assume that the circuit is RCD protected. Do you really want to
trust your life (and the lives of family and friends) to a piece of
mechanical equipment that is not 100% reliable? All for the sake of
a few pounds.

How is anyone going to get killed (or even injured) by it? One's life
doesn't depend on the operation of a pond pump usually.

The pond pumps I've seen have mains cables going underwater. Seems like
they
rely very much on maintaining the insulation and seals. Replacing the
cable
will inevitably disturb these, and if you do get it wrong, then it's not
the
operation of the pump which you're worried about, it's the elecric water
feature you now have.

That still doesn't explain how I (or anyone else) gets killed by it,
how does the 'electric water' get to you?


One is standing in the garden and dangles ones fingers in the pretty
waterfall. Or similar.

.... and how do you thereby get a voltage between your fingers and the
ground? It just doesn't add up, the water (which the pump is immersed
in) is sitting in a hole in the ground, it would need a fair amount of
current before that could be at any significant potential above that
of the earth in general.

--
Chris Green


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On 8 Aug 2006 03:53:22 -0700 someone who may be "Kev"
wrote this:-

In which case surely the RCD would trip.


It should do and in nearly all cases will. However, the question is
whether the small risk that it will not trip is worth it considering
that the pump would cost little to replace.

I can see why the manufacturers encapsulate the stator and the cable
leading to it in resin. Less to manufacture and less to go wrong
after it is sold, including less for people to fiddle with.
Watertight connections that will last for decades under water are a
difficult thing to make and usually involve encapsulation of the
joint.

Having said that I wish I could more than ten years out of a
submersible pump.


Is long life not one of the things surface pumps are for?

If the RCD were to go while on holiday the ruined contents of your
freezer are more than the replacement cost of the pump.


Indeed, if the house electrical system is designed that way.


--
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
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Douglas de Lacey wrote:
steeler wrote:
"Clive George" wrote in message
...
wrote in message
.. .


I admit I was puzzled too; you mean "when the bodge funally breaks
down", right? I do have an RCD on the circuit; would that not
immediately trip? In which case only the fish are likely to be in any
danger.


It would in 99+% of cases trip, yes. Whether the fish would survive
that depends. RCDs can occasionally fail though.


and various other equally unlikely options.


Yes, I get the impression that "unlikely" is the key term. Anyone want a
*free* (but useless) pond pump?
(But I would like to know whether the RCD might fail to function
immediately the electrons begin to escape. What's the resistivity of
pond-water?)


Although most of those sound unlikely, a mix of silicone and plastic
fibres would put a new sheath on the cable that would be as safe as the
existing one, and its an easy job. Just ensure a decent seal to the
pump body, ie thoroughly clean and abrade, and ensure a reasonable
coating thickness all over. Cost £1.50, time taken 15 minutes.


NT

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Kev wrote:

In which case surely the RCD would trip. Seeing the minute amounts of
condensation that cause my RCD to trip I have absolute confidence that
water ingress into a pump would give the RCD no problems with
detection.


no safety method is failure proof, hence we use several in combination
to get excellent safety.

Having said that I wish I could more than ten years out of a
submersible pump. I have just had to chuck a 3000 gallon per hour pump
away that tripped the RCD due to very slight water ingress through a
worn cable. The pump ran quite happliy on an unprotected circuit. This
was a £200 pump. It was repairable but coming close to £200 to repair
it was it worth it. It was 10 years old so time for the dump.


cables can be replaced and the pump resealed in minutes. Applying dc
first would get rid of much of the ingress.


NT

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David Hansen wrote:

Indeed, if the house electrical system is designed that way.


Although my fridge and freezer is on an unprotected circuit I have a
smaller freezer in the garage on a protected circuit so 2 years ago
when I came back from holiday to find the RCD tripped I reset it
forgetting about the freezer in the garage.
Two weeks later I remembered the freezer in the garage. You can't
imagine how much even frozen solid rotten fish stinks.

Kevin

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Frank Erskine wrote:

Seriously, I'd like to do a bit of a Gedankexperiment. As I said, the
rubber outer has degraded badly and there are places where the inner
cables are exposed. If either of positive or neutral sheath degrades, we
are in danger of David's worst case scenario. Could this be ameliorated
with a 4-core cable, with a second earth just left exposed at the pump
inlet? (I don't know where the present earth goes, but the pump appears
to be exclusively plastic and ceramic at the accessible level.) Or could
I simply earth the pond?


Is this pump mains-driven, or 24V?

Mains driven, at mains voltage. Via RCD, of course.
Douglas de Lacey
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Douglas de Lacey wrote:

Thanks very much:-)
Seriously, I'd like to do a bit of a Gedankexperiment. As I said, the
rubber outer has degraded badly and there are places where the inner
cables are exposed. If either of positive or neutral sheath degrades, we
are in danger of David's worst case scenario. Could this be ameliorated
with a 4-core cable, with a second earth just left exposed at the pump
inlet?


I dont see how this would solve the risk problem.

(I don't know where the present earth goes, but the pump appears
to be exclusively plastic and ceramic at the accessible level.) Or could
I simply earth the pond?


Pond is already earthed. Solutions have already been explained. Taking
strips of 100% synthetic cloth, squish silicone into them and applying
would give a reinforced waterproof outer sheath.


NT

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Douglas de Lacey wrote:
I have an old pump (Lotus "Little Gem") which is still working fine (so
am loath to throw it away) but the cable is becoming very degraded: the
outer rubber cover is cracking away in several places. As far as I can
see the cable just disappears into a lump of resin(?) in the body of the
pump. Any thoughts about digging this out and replacing it (with
silicone?) -- or am I really onto a loser here?

Douglas de Lacey


Hoe about heat-shrink sleeving + good dollop of silicone where it
enters the pump? You need only do the underwater bit that way. If it's
bad all the way up the garden, you can use something like
http://www.tlc-direct.co.uk/Products/BRH65Z.html to splice on the rest.
I'm assuming that H-SS is OK for immersion and UV-proof You could add
an outer sheath of hosepipe for good measure.

Chris

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