I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I
should be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use
1mm2, whilst for 40-60m they recommend 1.5mm2. Is the voltage drop
down an extension cable so large that it significantly affects the
mower? Or is this just more elfin safety nonsense? The mower is rated
at 1800w.

What type of plugs and sockets are you intending to use on this lead?

--

Adam

On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.



Voltage drop over a long/to small cable is a big problem with a pressure
washer that has an induction motor - it causes overheating.

Lawn mower is going to have a universal motor, not sure if the same
thing applies.

--
Dave - The Medway Handyman www.medwayhandyman.co.uk

GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I
should be okay with 1mm2 2 core cable.

Can you direct me to a source for 40m extension cables that have no earth?

Also, they recommend that for up to 40m of cable it is okay to use
1mm2, whilst for 40-60m they recommend 1.5mm2. Is the voltage drop
down an extension cable so large that it significantly affects the
mower? Or is this just more elfin safety nonsense? The mower is rated
at 1800w.

GB wrote:
I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2.

for 1800W a cable sizing calculator shows 1.5mm^2 for a run of 27m and
2.5mm^2 for a run of 41m, any longer than 66m and it'd need 4mm^2

To be fair the calculator is aimed at fixed wiring rather than an
extension lead, but it's reasonable to assume you want under a 10% drop.

Is the voltage drop down an extension cable so large that it
significantly affects the mower? Or is this just more elfin safety
nonsense? The mower is rated at 1800w.

26m of 1mm^2 drop 9V
27m of 1.5mm^2 drops 6V
40m of 1.5mm^2 drop 9V
60m of 2.5mm^2 drops 8.5V

On 24/05/2014 20:33, ARW wrote:


What type of plugs and sockets are you intending to use on this lead?

--

Adam

Hi Adam, I take it that the wrong answer is a 3 pin trailing socket,
with the join wrapped in a Tesco carrier bag, however traditional an
approach that is?

The lead that came with it has a standard 3 pin plug at one end and a 2
pin female plug at the other. My preferred solution will be to find a
replacement 2 pin plug and make up a cable that is long enough without a
join in it. I'm struggling to find the right sort of plug sold separately.

On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.



Almost all electrical appliances should be fitted with a plug, and that
would almost invariably be a standard 13 amp one. So that has to plug
into a 13 amp socket. Any extension lead with a 13 amp trailing socket
would have to be earthed because there no way of preventing its use with
equipment that requires an earth.

As I see it, if you change the supplied plug for a two-pin design, and
plug that into a two-core extension lead, you should be fine.

--
Rod

On 24/05/2014 21:05, GB wrote:
On 24/05/2014 20:33, ARW wrote:


What type of plugs and sockets are you intending to use on this lead?

--

Adam

Hi Adam, I take it that the wrong answer is a 3 pin trailing socket,
with the join wrapped in a Tesco carrier bag, however traditional an
approach that is?

The lead that came with it has a standard 3 pin plug at one end and a 2
pin female plug at the other. My preferred solution will be to find a
replacement 2 pin plug and make up a cable that is long enough without a
join in it. I'm struggling to find the right sort of plug sold separately.

The lead it came with looks identical to this:

http://www.espares.co.uk/product/es1...nceTypeId=1116

On 24/05/2014 20:48, The Medway Handyman wrote:
On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.



Voltage drop over a long/to small cable is a big problem with a pressure
washer that has an induction motor - it causes overheating.

Lawn mower is going to have a universal motor, not sure if the same
thing applies.

Some "quiet" mowers have induction motors these days (which have the
ideal torque curve for mowing grass when you think about it)


--
Cheers,

John.

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

On 24/05/2014 21:07, GB wrote:
On 24/05/2014 21:05, GB wrote:
On 24/05/2014 20:33, ARW wrote:


What type of plugs and sockets are you intending to use on this lead?

--

Adam

Hi Adam, I take it that the wrong answer is a 3 pin trailing socket,
with the join wrapped in a Tesco carrier bag, however traditional an
approach that is?

The lead that came with it has a standard 3 pin plug at one end and a 2
pin female plug at the other. My preferred solution will be to find a
replacement 2 pin plug and make up a cable that is long enough without a
join in it. I'm struggling to find the right sort of plug sold
separately.

The lead it came with looks identical to this:

http://www.espares.co.uk/product/es1...nceTypeId=1116



I think this is the correct plug:
http://www.appliancespareswarehouse....FckJwwod0HAAew

If you Google for orange 2-core cable, you'll get lots of hits, but you
may struggle to find any that's more than 1.0mm^2. The RS site has a
2.5mm^2 version, but it's shown as discontinued.

You'll get 2.5mm^2 in 3-core easily enough - but that's not really what
you want. It does need to be suitable for outdoor use, which usually
means that it will be orange.

As an alternative, if you don't mind an intermediate connector and don't
mind the first part being 3-core, you could consider buying a long
hook-up cable as used by caravanners, like this:
http://www.amazon.co.uk/230v-Caravan.../dp/B0025T6DD2.

Then simply swap the blue male plug with the 13A plug on your existing
cable, and connect the cables end to end.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

Lets say its 1800W, and a universal motor. So current = 1800/230 = 7.8A

1mm^2 flex has approx 18.1 mOhms/metre resistance. Voltage drop
therefore = 7.8^2 x 40 x 0.018 = ~44V

So pretty excessive even at 40m...


--
Cheers,

John.

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

John Rumm wrote:
On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

Lets say its 1800W, and a universal motor. So current = 1800/230 = 7.8A

1mm^2 flex has approx 18.1 mOhms/metre resistance. Voltage drop
therefore = 7.8^2 x 40 x 0.018 = ~44V

So pretty excessive even at 40m...



Try again time!! Hint IR!

"GB" wrote in message
...
I got a new electric mower today - Bosch Rotak 430.
May I ask where from and how much?
http://www.diy.com/nav/garden/garden...oCookies=false

GB wrote:
On 24/05/2014 20:33, ARW wrote:


What type of plugs and sockets are you intending to use on this lead?

--

Adam

Hi Adam, I take it that the wrong answer is a 3 pin trailing socket,
with the join wrapped in a Tesco carrier bag, however traditional an
approach that is?

The lead that came with it has a standard 3 pin plug at one end and a
2 pin female plug at the other. My preferred solution will be to find
a replacement 2 pin plug and make up a cable that is long enough
without a join in it. I'm struggling to find the right sort of plug
sold separately.

Well it looks like Roger has found part you need. I was going to suggest
http://www.screwfix.com/p/masterplug...240v-45m/47295
as it could be used for more than one use!

As far as I can tell the manufacturer is probably worried about people
making up their own 3 pin extension leads using two core flex -something
that could be unsafe if it was used with another appliance.

Of course it goes without saying that the mower lead needs RCD protection.

If you are wanting waterproof connections as an option to no connections
then 2 pin plugs and sockets are available - they are similar to the flymo
connectors but do not have the cover on the socket.

Cheers

--
Adam.

In article ,
says...
Voltage drop over a long/to small cable is a big problem with a pressure
washer that has an induction motor - it causes overheating.


Especially when someone has a very long cable & uses it whilst keeping
most of it coiled up.


--
Sam

On 24/05/2014 22:54, Capitol wrote:
John Rumm wrote:
On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

Lets say its 1800W, and a universal motor. So current = 1800/230 = 7.8A

1mm^2 flex has approx 18.1 mOhms/metre resistance. Voltage drop
therefore = 7.8^2 x 40 x 0.018 = ~44V

So pretty excessive even at 40m...



Try again time!! Hint IR!

Doh, yup make that 44W dissipated ;-)

I thought that sounded like an awful lot of volts!



--
Cheers,

John.

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

GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.



Maybe it is so when you cut it in half with the mower it will trip the
safety switch?

F Murtz wrote:

GB wrote:

It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

Maybe it is so when you cut it in half with the mower it will trip the
safety switch?

When you hack through the lead with the mower, if the current from the
live wire goes /anywhere/ other than back via the neutral wire, the RCD
will trip. That is to say, that though you or through wet grass to the
actual earth is as "good" as returning via an earth wire, unless you
don't have an RCD/RCBO, but there's not much excuse not to ...

Well, some time ago I had to take apart an old eclectic mowere, it had three
core cable attached, though the earth appeared not to be used at all. In a
strimmer it had 2 core.
I guess from the extension lead point of view it depends on how the
protection works at the plug end what you use.

The weird thing is that I've also seen 2 and three core versions of those
connection extenders that have a quick release as well.

As for drop, yes you get one heck of a drop when you start the motor up I
found. If you don't believe it, wire a light bulb across the mower end.
Brian
Brian

--
From the Sofa of Brian Gaff Reply address is active
"GB" wrote in message
...
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads. It
says "your machine is double insulated and requires no earth connection".
Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit out
of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable and
the extra cost and weight of an earth wire is significant. I should be
okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

When I was losing my sight I used white cable, which seemed to survive OK
outside. I understand it can be a problem in sun, but then I was never out
in the sun long enough. It was very hardy to mechanical damage, an much
less a problem with tangling than the orange stuff which seemed to be far
more stiff.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Roger Mills" wrote in message
...
On 24/05/2014 21:07, GB wrote:
On 24/05/2014 21:05, GB wrote:
On 24/05/2014 20:33, ARW wrote:


What type of plugs and sockets are you intending to use on this lead?

--

Adam

Hi Adam, I take it that the wrong answer is a 3 pin trailing socket,
with the join wrapped in a Tesco carrier bag, however traditional an
approach that is?

The lead that came with it has a standard 3 pin plug at one end and a 2
pin female plug at the other. My preferred solution will be to find a
replacement 2 pin plug and make up a cable that is long enough without a
join in it. I'm struggling to find the right sort of plug sold
separately.

The lead it came with looks identical to this:

http://www.espares.co.uk/product/es1...nceTypeId=1116



I think this is the correct plug:
http://www.appliancespareswarehouse....FckJwwod0HAAew

If you Google for orange 2-core cable, you'll get lots of hits, but you
may struggle to find any that's more than 1.0mm^2. The RS site has a
2.5mm^2 version, but it's shown as discontinued.

You'll get 2.5mm^2 in 3-core easily enough - but that's not really what
you want. It does need to be suitable for outdoor use, which usually means
that it will be orange.

As an alternative, if you don't mind an intermediate connector and don't
mind the first part being 3-core, you could consider buying a long hook-up
cable as used by caravanners, like this:
http://www.amazon.co.uk/230v-Caravan.../dp/B0025T6DD2.

Then simply swap the blue male plug with the 13A plug on your existing
cable, and connect the cables end to end.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.



I would use an extension cable. In the past I've had problems with very
long leads getting twisted and consequently tangled. Probably due to the
way I coil them up when I pack them.

I have wondered if I alternately use left or right hands when coiling I
might avoid the twist but have never managed it in practice.

On 25/05/2014 01:03, Sam Plusnet wrote:
In article ,
says...
Voltage drop over a long/to small cable is a big problem with a pressure
washer that has an induction motor - it causes overheating.


Especially when someone has a very long cable & uses it whilst keeping
most of it coiled up.


I think TMH meant overheating of the motor.

I loaned a builder an extension reel for use with his steamer. It never
occurred to me to say that he needed to unroll it all for a heavy usage
appliance like that. I thought it was obvious, besides it being written
on the reel.

A few minutes later, the ring main went off, and I found that the
extension reel had melted completely, just a pile of melted vinyl and
conductors on the floor.

On 24/05/2014 23:22, bm wrote:
"GB" wrote in message
...
I got a new electric mower today - Bosch Rotak 430.
May I ask where from and how much?
http://www.diy.com/nav/garden/garden...oCookies=false


Indeed, but I fear they will all have gone by now. Apparently, the
feeding frenzy over the £10 garden chairs was even more intense.



Amazon price-matched the mower, and apparently the really clever money
was on using Flubit to knock an extra £10 off that. Too clever for me,
though.

On 24/05/2014 22:47, Roger Mills wrote:

I think this is the correct plug:
http://www.appliancespareswarehouse....FckJwwod0HAAew

Thanks very much - just the one.





If you Google for orange 2-core cable, you'll get lots of hits, but you
may struggle to find any that's more than 1.0mm^2. The RS site has a
2.5mm^2 version, but it's shown as discontinued.

I'm just going to go out and measure it, but I'm hoping I'll be okay
with 40m of extension or a complete cable length of 55m.






You'll get 2.5mm^2 in 3-core easily enough - but that's not really what
you want. It does need to be suitable for outdoor use, which usually
means that it will be orange.

As an alternative, if you don't mind an intermediate connector and don't
mind the first part being 3-core, you could consider buying a long
hook-up cable as used by caravanners, like this:
http://www.amazon.co.uk/230v-Caravan.../dp/B0025T6DD2.

Then simply swap the blue male plug with the 13A plug on your existing
cable, and connect the cables end to end.

On 25/05/2014 10:46, GB wrote:
On 24/05/2014 22:47, Roger Mills wrote:

I think this is the correct plug:
http://www.appliancespareswarehouse....FckJwwod0HAAew

Thanks very much - just the one.

B&Q have a similar looking plug and socket:
http://www.diy.com/nav/fix/electrica...skuId=13249272

However, their version of the classic 2 pin plug and socket:
http://www.diy.com/nav/fix/electrica...skuId=13249298
isn't quite compatible with a non-B&Q version so that might also apply to the flymo-style pair.

If you Google for orange 2-core cable, you'll get lots of hits, but you
may struggle to find any that's more than 1.0mm^2. The RS site has a
2.5mm^2 version, but it's shown as discontinued.

I'm just going to go out and measure it, but I'm hoping I'll be okay
with 40m of extension or a complete cable length of 55m.


If you can find a supplier, buying a pre-packaged 50m drum is likely to
be cheaper than buying 40m by the metre.

I see Rod ('polygonum') has already covered why you mustn't fit a 3-pin
socket to a 2-core flex.


Graham Nye
news(a)thenyes.org.uk

Nick wrote:

In the past I've had problems with very long leads getting twisted
and consequently tangled. Probably due to the way I coil them up when
I pack them.

I have wondered if I alternately use left or right hands when coiling
I might avoid the twist but have never managed it in practice.

Do the roadie wrap!

http://youtu.be/yqbYyaUY5Sk

In article , John
Rumm scribeth thus
On 24/05/2014 22:54, Capitol wrote:
John Rumm wrote:
On 24/05/2014 20:26, GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

Lets say its 1800W, and a universal motor. So current = 1800/230 = 7.8A

1mm^2 flex has approx 18.1 mOhms/metre resistance. Voltage drop
therefore = 7.8^2 x 40 x 0.018 = ~44V

So pretty excessive even at 40m...



Try again time!! Hint IR!

Doh, yup make that 44W dissipated ;-)

I thought that sounded like an awful lot of volts!




Best answer is to put the electric one on fleabay, local paper etc and
get a Petrol driven one. Apart from a bit of annual faffing around with
the spark plug they just work and work well and no risk of cables
getting cut bound up possible electric schnocks etc.

My lawn servant operative wouldn't have anything other than lead less
bless her....

--
Tony Sayer

In article ,
GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

Assuming it has a 13 amp plug and socket, that makes sense. As you simply
can't be sure it won't be used elsewhere where an earth is needed.

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

I'm pretty certain if you change the plug on the mower to one of those
special garden tool types you can then use a two core lead to that.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

Voltage drop to anything can be a problem.

--
*Virtual reality is its own reward*

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

On 25/05/2014 11:41, Andy Burns wrote:
Nick wrote:

In the past I've had problems with very long leads getting twisted
and consequently tangled. Probably due to the way I coil them up when
I pack them.

I have wondered if I alternately use left or right hands when coiling
I might avoid the twist but have never managed it in practice.

Do the roadie wrap!

http://youtu.be/yqbYyaUY5Sk

Thanks, this looks to be a solution to the problem. I will try it out.

On 25/05/2014 12:22, tony sayer wrote:

Best answer is to put the electric one on fleabay, local paper etc and
get a Petrol driven one. Apart from a bit of annual faffing around with
the spark plug they just work and work well and no risk of cables
getting cut bound up possible electric schnocks etc.

My lawn servant operative wouldn't have anything other than lead less
bless her....

Yup, for all its various other faults, my Hayter is over 20 years old
now, and has never done anything other than start first time...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
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\================================================= ================/

On 25/05/2014 06:22, F Murtz wrote:
GB wrote:
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads.
It says "your machine is double insulated and requires no earth
connection". Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit
out of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable
and the extra cost and weight of an earth wire is significant. I should
be okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.



Maybe it is so when you cut it in half with the mower it will trip the
safety switch?

Unlikely. You're most likely to cut the bit nearest the mower - which is
the original 2-core cable.
--
Cheers,
Roger
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Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

"GB" wrote in message
...
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads. It
says "your machine is double insulated and requires no earth connection".
Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit out
of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable and
the extra cost and weight of an earth wire is significant. I should be
okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.

don't bother with an extension lead, just get a generator and position it
halfway down the garden, then the origional lead on the mower should reach
everywhere

"GB" wrote in message
...
I got a new electric mower today - Bosch Rotak 430. I am puzzled, very
puzzled, by the manual that comes with it, concerning extension leads. It
says "your machine is double insulated and requires no earth connection".
Protection class is II.

Yet, when it describes extension leads, it says "Note: If an extension
lead is used it must be earthed and connected through the plug to the
earth cable of your electricity supply..."

That makes no sense to me. Is it just a ****-up? They've copied a bit out
of another manual for a machine that is earthed?

This matters a bit, because I'll need probably 40m of extension cable and
the extra cost and weight of an earth wire is significant. I should be
okay with 1mm2 2 core cable.

Also, they recommend that for up to 40m of cable it is okay to use 1mm2,
whilst for 40-60m they recommend 1.5mm2. Is the voltage drop down an
extension cable so large that it significantly affects the mower? Or is
this just more elfin safety nonsense? The mower is rated at 1800w.



The mower has two layers of insulation & needs no earth.
The cable needs and earth in case you run over it with the mower.
Also the extension cable reel may have metal parts that need to be earthed.

On Sun, 25 May 2014 11:38:05 +0100, Graham Nye wrote:

I'm just going to go out and measure it, but I'm hoping I'll be okay
with 40m of extension or a complete cable length of 55m.

If you can find a supplier, buying a pre-packaged 50m drum is likely to
be cheaper than buying 40m by the metre.

I see Rod ('polygonum') has already covered why you mustn't fit a 3-pin
socket to a 2-core flex.

That's what I did and, at the time Wilko was cheaper than SF and TS.
I made my own because pretty well all of the 25m leads were 1.25mm^2 and I
wanted 1.5; also 27m is just the right length. 30m would have been OK of
course but most are 1.25.
--
Peter.
The gods will stay away
whilst religions hold sway

On 25/05/2014 17:27, harryagain wrote:

The mower has two layers of insulation& needs no earth.
The cable needs an earth in case you run over it with the mower.

In that case, how do you explain the fact that the cable supplied with
the mower has only two cores?
--
Cheers,
Roger
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Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Roger Mills wrote:
On 24/05/2014 21:07, GB wrote:
You'll get 2.5mm^2 in 3-core easily enough - but that's not really
what you want. It does need to be suitable for outdoor use, which
usually means that it will be orange.

That just Network rails extension leads:-) - everyone else uses yellow
ones.

--

Adam

On 25/05/2014 17:27, harryagain wrote:

The cable needs [an] earth in case you run over it with the mower.

No, it doesn't. An RCD at the house end will provide protection to
the user in this event.

Also the extension cable reel may have metal parts that need to be earthed.

Then don't use a metal cable reel with a 2-core flex. Better still, don't
use a metal cable reel at all. If you're standing on damp ground there's
no sense in introducing unnecessary lumps of metal connected to any part
of the mains electric supply.


--
Graham Nye
news(a)thenyes.org.uk

On 25/05/2014 21:56, ARW wrote:
Roger Mills wrote:
On 24/05/2014 21:07, GB wrote:
You'll get 2.5mm^2 in 3-core easily enough - but that's not really
what you want. It does need to be suitable for outdoor use, which
usually means that it will be orange.

That just Network rails extension leads:-) - everyone else uses yellow
ones.

I just looked at Screwfix. They seem to have yellow for 110V only, blue
or -- you'll never guess this -- ORANGE for 240V.

Andy
--
p.s. you need a space after the hyphens in your sig.

On 25 May 2014, GB grunted:

On 25/05/2014 01:03, Sam Plusnet wrote:
In article ,
says...
Voltage drop over a long/to small cable is a big problem with a
pressure washer that has an induction motor - it causes overheating.


Especially when someone has a very long cable & uses it whilst
keeping most of it coiled up.


I think TMH meant overheating of the motor.

I loaned a builder an extension reel for use with his steamer. It
never occurred to me to say that he needed to unroll it all for a
heavy usage appliance like that. I thought it was obvious, besides it
being written on the reel.

+1. I'd owned it for years...

A few minutes later, the ring main went off, and I found that the
extension reel had melted completely, just a pile of melted vinyl and
conductors on the floor.

+1

--
David

On 25 May 2014, tony sayer grunted:

Best answer is to put the electric one on fleabay, local paper etc and
get a Petrol driven one. Apart from a bit of annual faffing around
with the spark plug they just work and work well and no risk of cables
getting cut bound up possible electric schnocks etc.

But do they really 'just work'? Certainly my electric mower does...
When I was a youngster living at home I have many 'happy' memories of
sweating blood trying to get my Dad's Mountfield going, and have never been
in any hurry to own a petrol-engined machine of my own.

--
David