I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?

--
*Always borrow money from pessimists - they don't expect it back *

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

Dave Plowman (News) wrote:
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?


No. If the battery charger is double insulated, then the only issue is
preventing the chassis becoming live from a fault on the mains cable.
Cover the mains lead in plastic conduit and ensure that it can't chafe
or snag on anything. Make sure you plug in to an RCD-protected supply.

Dave Osborne gurgled happily, sounding much like
they were saying:

I'm thinking of building in one of those Lidl battery chargers in the
old car. So it can be left on float when not in use. The mains lead on
those is only two core and the case plastic. I was considering a
Buccaneer weather proof mains connector mounted in the body below the
rear bumper. Should the car body be connected to mains earth?

No. If the battery charger is double insulated, then the only issue is
preventing the chassis becoming live from a fault on the mains cable.
Cover the mains lead in plastic conduit and ensure that it can't chafe
or snag on anything. Make sure you plug in to an RCD-protected supply.

Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.

Motorbike Optimate-style.

"Dave Plowman (News)" wrote in message
...
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?

--
*Always borrow money from pessimists - they don't expect it back *

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

How about "dodgem car" style.

Park one wheel on a metal plate and some kind of ceiling contact. Ground
the plate as well.

I've got no idea how many ohms a tyre would present in circuit...but surely
a small enough figure to trickle charge a battery?

On 16 Dec 2009 09:51:33 GMT, Adrian wrote:

Dave Osborne gurgled happily, sounding much like
they were saying:

I'm thinking of building in one of those Lidl battery chargers in the
old car. So it can be left on float when not in use. The mains lead on
those is only two core and the case plastic. I was considering a
Buccaneer weather proof mains connector mounted in the body below the
rear bumper. Should the car body be connected to mains earth?

No. If the battery charger is double insulated, then the only issue is
preventing the chassis becoming live from a fault on the mains cable.
Cover the mains lead in plastic conduit and ensure that it can't chafe
or snag on anything. Make sure you plug in to an RCD-protected supply.

Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.

Motorbike Optimate-style.

That's what I have done.

My Halfords 'maintenance' charger came with both croc clips and also a
set of flying leads that could be permanently bolted to the battery
terminals with an in-line shrouded connector that matches the one on
the charger. So to do a trickle charge, I simply open the bonnet and
quickly hook up the flying leads to the charger. A red/green led
indicates when the battery is fully charged.

David

This is actually something that was covered in the most recent edition
(17th) of the wiring regulations, in relation to power hook-ups in
caravans and motorhomes.

Basically the regs say that caravans and motorhomes must have metallic
bodies/chassis earth bonded, along with RCD protection on the hook-up.

Presumably the reasoning behind bonding is that should there be a
fault that caused the body to become live, it could present the most
dangerous scenario of someone barefoot outside the vehicle touching
live bodywork.

That's all well and good in places like UK campsites with properly
tested hook-ups that have both a good earth and RCD protection.

It's not so good on places where there's a dodgy earth, or the
possibility of live/earth being transposed.

So - practically - do what you feel is safest in the locations you
will use your charger hook-up. Not bonding and carefully protecting
the cable sounds reasonable, if you're the only user and use it in
locations you trust.

An approach popular with many van users is to use a "tent power hook-
up". This is basically a mains plug on one end (often a commando) and
a mini-consumer unit on the other.

e.g. http://www.camping-caravan-outdoors....f.asp?item=876

With some vehicles (well VW T4 vans for definite) you can pop a
reflector out of the rear bumper and feed the plug and lead from the
consumer unit outside the vehicle, or even mount a connector there.

On untrusted locations, one of those mains test plugs to check
polarity of the wiring and the presence of some sort of earth, is a
cheap and quick way of getting an indication that all may not be well.

On 16 Dec, 09:51, Adrian wrote:
Dave Osborne gurgled happily, sounding much like
they were saying:

I'm thinking of building in one of those Lidl battery chargers in the
old car. So it can be left on float when not in use. The mains lead on
those is only two core and the case plastic. I was considering a
Buccaneer weather proof mains connector mounted in the body below the
rear bumper. Should the car body be connected to mains earth?
No. If the battery charger is double insulated, then the only issue is
preventing the chassis becoming live from a fault on the mains cable.
Cover the mains lead in plastic conduit and ensure that it can't chafe
or snag on anything. Make sure you plug in to an RCD-protected supply.

Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.

Motorbike Optimate-style.

The extra-low voltage option would be by far the safest solution. If
you really do want to put a 230v mains supply into the car then use a
3 core flex with a trailing socket and a 3 pin mains rated connector
at the car end. Earth the car via the earth pin of the connector.
Also use a supply with 30mA RCD protection (which all sockets rated at
less than 20A, intended to supply equipment for use out of doors
should have for additional personal protection in the event of a fault)

On 16 Dec, 09:51, Adrian wrote:

Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.

Voltage drop in the cables screws with measuring float voltage. Where
this is done commercially, it's a 4-lead setup back to the sense input.

On Wed, 16 Dec 2009 09:24:16 +0000, Dave Plowman (News) wrote:
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?

FWIW, engine block heaters and battery conditioners are *very* common
in these parts - I'm not aware of any of them typically being grounded,
but then they always seem to have a little bit of trailing flex and
socket, rather than a socket mounted rigidly to the vehicle's body.

(I'm not sure how well a cheap battery charger will stand up to permanent
connection and repeated starts with it connected? I expect - but
don't know for sure - that a proper conditioner is designed to be a
bit more robust in that regard)

cheers

Jules

In article . com,
Jules wrote:
(I'm not sure how well a cheap battery charger will stand up to permanent
connection and repeated starts with it connected? I expect - but
don't know for sure - that a proper conditioner is designed to be a
bit more robust in that regard)

The Lidl charger is only cheap in price. It's an extremely sophisticated
design. Those 'proper' conditioners are often a con price wise - for what
amounts to little more than low power DC supply with a few added
components.

--
*I have my own little world - but it's OK...they know me here*

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

In article
,
wrote:
This is actually something that was covered in the most recent edition
(17th) of the wiring regulations, in relation to power hook-ups in
caravans and motorhomes.

Basically the regs say that caravans and motorhomes must have metallic
bodies/chassis earth bonded, along with RCD protection on the hook-up.

Thanks - that's what I'll do. Although I wasn't intending having any mains
outlets in the car. ;-)

--
*If you can read this, thank a teecher

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

In article
,
Andy Dingley wrote:
On 16 Dec, 09:51, Adrian wrote:

Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.

Voltage drop in the cables screws with measuring float voltage. Where
this is done commercially, it's a 4-lead setup back to the sense input.

Rather guessed something like that would apply.

--
*Be nice to your kids. They'll choose your nursing home.

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

In article ,
Adrian wrote:
Dave Osborne gurgled happily, sounding much like
they were saying:

I'm thinking of building in one of those Lidl battery chargers in the
old car. So it can be left on float when not in use. The mains lead on
those is only two core and the case plastic. I was considering a
Buccaneer weather proof mains connector mounted in the body below the
rear bumper. Should the car body be connected to mains earth?

No. If the battery charger is double insulated, then the only issue is
preventing the chassis becoming live from a fault on the mains cable.
Cover the mains lead in plastic conduit and ensure that it can't chafe
or snag on anything. Make sure you plug in to an RCD-protected supply.

Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.

Motorbike Optimate-style.

I'd rather a neater way. The charger will fit nicely in a dead space
alongside the spare wheel.

--
*Very funny Scotty, now beam down my clothes.

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

Dave Osborne pretended :
No. If the battery charger is double insulated, then the only issue is
preventing the chassis becoming live from a fault on the mains cable. Cover
the mains lead in plastic conduit and ensure that it can't chafe or snag on
anything. Make sure you plug in to an RCD-protected supply.

I do it the other way around...

Lidl charger is in a bracket, up in the garage roof, with a 12v cable
fitted with a ciggy plug dangling down to car. As I park, I pull the
ciggy plug in and plug it in. The ciggy socket has to be the type which
is on all the time, which depends upon the car.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article ,
Harry Bloomfield wrote:
Dave Osborne pretended :
No. If the battery charger is double insulated, then the only issue is
preventing the chassis becoming live from a fault on the mains cable.
Cover the mains lead in plastic conduit and ensure that it can't
chafe or snag on anything. Make sure you plug in to an RCD-protected
supply.

I do it the other way around...

Lidl charger is in a bracket, up in the garage roof, with a 12v cable
fitted with a ciggy plug dangling down to car. As I park, I pull the
ciggy plug in and plug it in. The ciggy socket has to be the type which
is on all the time, which depends upon the car.

That's fine if you have a garage...

--
*Why 'that tie suits you' but 'those shoes suit you'?*

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

The ciggy socket has to be the type which
is on all the time, which depends upon the car.

I have wondered why that varies between manufacturers. Mine does, and
it's very useful to leave a camera or phone tucked away and on charge
sometimes.

expressed precisely :
I have wondered why that varies between manufacturers. Mine does, and
it's very useful to leave a camera or phone tucked away and on charge
sometimes.

Better would be cars fitted with a switch so the driver could select
how he wanted the socket to operate.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Vortex4 explained :
Park one wheel on a metal plate and some kind of ceiling contact. Ground the
plate as well.

I've got no idea how many ohms a tyre would present in circuit...but surely a
small enough figure to trickle charge a battery?

Several megs at least, so no.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Jules submitted this idea :
(I'm not sure how well a cheap battery charger will stand up to permanent
connection and repeated starts with it connected? I expect - but
don't know for sure - that a proper conditioner is designed to be a
bit more robust in that regard)

They (Lidl unit) will be fine. I have one in use like that for a few
years. My car can at times sit in the garage unused for weeks, so it is
often left with a Lidl unit connected. I have also had it charge flat
batteries up and it gets no more than luke warm.

The only down side, is if the mains goes off briefly - you need to
press a button to restart the charge.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

on 16/12/2009, Dave Plowman (News) supposed :
The Lidl charger is only cheap in price. It's an extremely sophisticated
design. Those 'proper' conditioners are often a con price wise - for what
amounts to little more than low power DC supply with a few added
components.

Agreed, I have three or four of them. One permanently set up to
maintain the car in the garage, one on the tractor, one in the caravan,
and a spare around somewhere - with an Optimate keeping the bikes
battery ready to go.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Dave Plowman (News) wrote:
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?

I would say yes. Treat the whole car as an appliance - it has a metal
case and can't be certified as double insulated, so the case must be
earthed.

Things get more complex for a boat, where galvanic corrosion in salt
water needs to be considered, but for a car I'd certainly connect the
body to the earth in the connector.

Pete

On Wed, 16 Dec 2009 04:39:49 -0800 (PST), Andy Dingley wrote:

On 16 Dec, 09:51, Adrian wrote:

Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.

Voltage drop in the cables screws with measuring float voltage. Where
this is done commercially, it's a 4-lead setup back to the sense input.

How about a nice hefty battery cable to a proper Anderson connector? You
can keep only the low voltage on the car then and there'd be next to no
voltage drop on the extra length of cable with the low current of a charger
and the large CSA. You'd also have the added bonus that you could use the
connector for a plug in set of jump leads. I keep meaning to get around to
doing this on my kit-car.

SteveW

In message , "Dave Plowman (News)"
writes
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?


I can go for several months without driving my car, but I do have a good
battery in it (and a solar plug in the cigarette lighter charger). I
just don't have problems


--
geoff

In article ,
geoff wrote:
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?


I can go for several months without driving my car, but I do have a good
battery in it (and a solar plug in the cigarette lighter charger). I
just don't have problems

I've got a fairly high quiescent draw on it - lots of extra junk fitted.
;-)

--
*Reality? Is that where the pizza delivery guy comes from?

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

After serious thinking Pete Verdon wrote :
I would say yes. Treat the whole car as an appliance - it has a metal case
and can't be certified as double insulated, so the case must be earthed.

Things get more complex for a boat, where galvanic corrosion in salt water
needs to be considered, but for a car I'd certainly connect the body to the
earth in the connector.

No one has suggested an earth rod )

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

"Owain" wrote in message
...
On 16 Dec, 09:51, Adrian wrote:
Or do it the other way round, and plug the low-voltage into the car,
keeping the charger.
Motorbike Optimate-style.

Or milk-float style?

http://groups.google.co.uk/group/uk....642746b0dfc4e8

Owain


That is a seriously inefficient charger.. 40x240 70x72

"Harry Bloomfield" wrote in message
. uk...
After serious thinking Pete Verdon wrote :
I would say yes. Treat the whole car as an appliance - it has a metal
case and can't be certified as double insulated, so the case must be
earthed.

Things get more complex for a boat, where galvanic corrosion in salt
water needs to be considered, but for a car I'd certainly connect the
body to the earth in the connector.

No one has suggested an earth rod )

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


That is because it is not an Audi TT.

Adam

Pete Verdon d
wibbled on Wednesday 16 December 2009 20:05

Dave Plowman (News) wrote:
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use. The mains lead on those
is only two core and the case plastic. I was considering a Buccaneer
weather proof mains connector mounted in the body below the rear bumper.
Should the car body be connected to mains earth?

I would say yes. Treat the whole car as an appliance - it has a metal
case and can't be certified as double insulated, so the case must be
earthed.

Things get more complex for a boat, where galvanic corrosion in salt
water needs to be considered, but for a car I'd certainly connect the
body to the earth in the connector.

Pete

I would agree with that. Earthing the car will be a better bet IMHO than
trying to insure that there is no way that a mains cable entering the car
cannot become damaged on a sharp with of metal and become live.

Another way would be to take the double insulated approach, but to use SY
flex to take the mains in and earth the braid.

That flex doesn't meet the mechanical protection criteria of the IEE regs in
way that armoured does, but looking at it objectively, if the outer sheath
does become cut, it will provide some mechanical and electrical protection.

But the obvious belt and braces approach, as others have mentioned is to
talk SELV into car.

Might be worth having a look at some engine preheaters - those are mains -
see what they do regarding earthing.

--
Tim Watts

This space intentionally left blank...

Tim W wrote:
Earthing the car will be a better bet IMHO than
trying to insure that there is no way that a mains cable entering the car
cannot become damaged on a sharp with of metal and become live.

Another way would be to take the double insulated approach, but to use SY
flex to take the mains in and earth the braid.

As long as you're not planning to take the SY flex into the battery
charger, which would defeat the double-insulated properties of the
charger and be more dangerous!


That flex doesn't meet the mechanical protection criteria of the IEE regs in
way that armoured does, but looking at it objectively, if the outer sheath
does become cut, it will provide some mechanical and electrical protection.

But the obvious belt and braces approach, as others have mentioned is to
talk SELV into car.

Might be worth having a look at some engine preheaters - those are mains -
see what they do regarding earthing.


It's worth pointing out that the reason Caravans and motor homes are
required to be earthed is because human beings occupy them naked and wet
when the mains electricity is connected.

In Dave's case, he's going to be fully dressed and he's going to
disconnect the mains before he gets into the car, so the risk of
electric shock is minimal.

However, there's no obvious downside to fitting a 3-pin inlet to the car
and earthing to the chassis/body. He should not under any circumstances,
however, consider modifying the charger from Class II to Class I (i.e
double insulated to earthed).


Cheers,
DaveyOz

Dave Osborne
wibbled on Thursday 17 December 2009 17:43

Tim W wrote:
Earthing the car will be a better bet IMHO than
trying to insure that there is no way that a mains cable entering the car
cannot become damaged on a sharp with of metal and become live.

Another way would be to take the double insulated approach, but to use
SY flex to take the mains in and earth the braid.

As long as you're not planning to take the SY flex into the battery
charger, which would defeat the double-insulated properties of the
charger and be more dangerous!

No, I was thinking of the SY flex being the flying lead used to plug the
charger into the house supply - that being the bit that is vulnerable to
chafing. The charger and its immediate wiring can be secured and protected.

I'm not sure I entirely agree that feeding an earth shielded flex into a
Class II appliance makes it dangerous though. What failure scenarios could
that cause that would result in a dangerous condition?

--
Tim Watts

This space intentionally left blank...

Tim W wrote:
Dave Osborne
wibbled on Thursday 17 December 2009 17:43

Tim W wrote:
Earthing the car will be a better bet IMHO than
trying to insure that there is no way that a mains cable entering the car
cannot become damaged on a sharp with of metal and become live.

Another way would be to take the double insulated approach, but to use
SY flex to take the mains in and earth the braid.
As long as you're not planning to take the SY flex into the battery
charger, which would defeat the double-insulated properties of the
charger and be more dangerous!

No, I was thinking of the SY flex being the flying lead used to plug the
charger into the house supply - that being the bit that is vulnerable to
chafing. The charger and its immediate wiring can be secured and protected.

I'm not sure I entirely agree that feeding an earth shielded flex into a
Class II appliance makes it dangerous though. What failure scenarios could
that cause that would result in a dangerous condition?


Class II appliances are designed such that if a live wire goes astray
inside the unit, there is no external metalwork which can become live.
(this is not, I stress, saying that there would be no external metalwork
at all).

In the event of a fault the unit will simply stop working or pop a fuse
(thermal or over-current), rather than become hazardous to touch. This
allows the manufacturer of the product to make the internal chassis
live, to have various different bits of internal metalwork at different
potentials, etc.

This, in turn, facilitates value engineering the design for minimal
production costs. It also allows the product designer to create a
product with mixed metal and plastic components (e.g. a hand-held
electric drill) without needing to ensure that there is contiguous earth
bonding within the unit.

By introducing an earth wire (or indeed armour/screening) into the
interior of the unit, you would then effectively make it a Class I
appliance. You would then have to make an electrical safety reassessment
of the product design. Depending on the nature of the product this could
be straightforward or it could be virtually impossible to achieve
without extensive design reworking.

Dave Osborne
wibbled on Thursday 17 December 2009 19:37


By introducing an earth wire (or indeed armour/screening) into the
interior of the unit, you would then effectively make it a Class I
appliance. You would then have to make an electrical safety reassessment
of the product design. Depending on the nature of the product this could
be straightforward or it could be virtually impossible to achieve
without extensive design reworking.

Yes - I agree with all of that in spirit. But I don't make formal electrical
assessments when I build mains devices from scratch, other than common
sense, sensible design and good workmanship. I've applied more consideration
in my devices to making sure that a SELV part cannot reasonably contact a
mains part (due to wire falling off) than I've observed in at least one
appliance I took to bits once which had all the relevant markings on it.

I've built Class I and Class II appliances and applied the relevant
engineering considerations to both.

My argument is that in this scenario, we have introduced an extraneous
metallic part - yes. But that part is earthed by design. I see very little
that can go wrong.

OK - if we were selling this to the general public, one would expect to make
a formalised assessment. However, as always, this is a one off for personal
use. It is of course down to whether the OP feels happy with doing such
stuff (this is a DIY group), but being aware of the cautions given I think
he's got reasonable grounds to make a judgement.

I'm merely presenting the engineering argument "what could go wrong"?

(As I said, I intended the SY flex to connect between the mains supply and a
recepticle in the car - but as we're starting to discuss the case of
modifying a Class II device, then why not - it's interesting.)

If we reduce the argument further, noone should put a plug on a class I
device because they might wire it incorrectly?

I'll just add, this is a "friendly argument" AFAIC as there's no way for you
to deduce that from the tone of my tapping ;-

Cheers

Tim

--
Tim Watts

This space intentionally left blank...

In article ,
Tim W wrote:
(As I said, I intended the SY flex to connect between the mains supply
and a recepticle in the car - but as we're starting to discuss the case
of modifying a Class II device, then why not - it's interesting.)

If we reduce the argument further, noone should put a plug on a class I
device because they might wire it incorrectly?

I'll just add, this is a "friendly argument" AFAIC as there's no way for
you to deduce that from the tone of my tapping ;-

The mains lead twixt 13 amp socket and Buccaneer inlet will be 1mm TRS.
The back of the chassis plug covered by a strong plastic box with a side
exit stuffing gland which the supplied mains lead on the charger will come
out of - a distance of only a few inches. Likely behind the boot carpet -
although that's not yet decided.

--
*What was the best thing before sliced bread? *

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

Tim W wrote:
Dave Osborne
wibbled on Thursday 17 December 2009 19:37


By introducing an earth wire (or indeed armour/screening) into the
interior of the unit, you would then effectively make it a Class I
appliance. You would then have to make an electrical safety reassessment
of the product design. Depending on the nature of the product this could
be straightforward or it could be virtually impossible to achieve
without extensive design reworking.

Yes - I agree with all of that in spirit. But I don't make formal electrical
assessments when I build mains devices from scratch, other than common
sense, sensible design and good workmanship. I've applied more consideration
in my devices to making sure that a SELV part cannot reasonably contact a
mains part (due to wire falling off) than I've observed in at least one
appliance I took to bits once which had all the relevant markings on it.

I've built Class I and Class II appliances and applied the relevant
engineering considerations to both.

My argument is that in this scenario, we have introduced an extraneous
metallic part - yes. But that part is earthed by design. I see very little
that can go wrong.

OK - if we were selling this to the general public, one would expect to make
a formalised assessment. However, as always, this is a one off for personal
use. It is of course down to whether the OP feels happy with doing such
stuff (this is a DIY group), but being aware of the cautions given I think
he's got reasonable grounds to make a judgement.

I'm merely presenting the engineering argument "what could go wrong"?

(As I said, I intended the SY flex to connect between the mains supply and a
recepticle in the car - but as we're starting to discuss the case of
modifying a Class II device, then why not - it's interesting.)

If we reduce the argument further, noone should put a plug on a class I
device because they might wire it incorrectly?

I'll just add, this is a "friendly argument" AFAIC as there's no way for you
to deduce that from the tone of my tapping ;-

Cheers

Tim


No real problem with anything you've said, Tim.

Unfortunately I can't take the discussion much further as I've never
worked for a company which mass-produces stuff to Class II, so it's all
personal opinion and speculation from here-on-in ;-)

I do suspect that when you say you've "scratch built to Class II" (to
paraphrase), you should probably say you've "scratch built without
earth". I think that you couldn't reasonably argue that you've
scratch-built a Class II appliance because the standard will likely have
all kinds of subtleties like creepage, clearance, dielectric strength of
plastics, flame-retardance, etc, etc. which you will not have been in a
position to consider (you don't have full specs for the materials used)
or test for (you likely don't have access to a proving laboratory with
all the required equipment). Also, I suspect that some of the tests are
destructive, so essentially Class II is a type approval.

I agree that if you're "scratch-building without earth" then it is
reasonable to apply good engineering practice and common sense. Very
often you're not reinventing the wheel, so you can confidently follow
standard practice. I would, however be very cautious about dismantling
an existing Class II appliance and re-engineering it because it may not
be obvious what abominations have been made to the design as part of a
value-engineering exercise which would not have been considered had the
item been an un-enclosed or Class I product.

For example, if I were building a piece of equipment into a 19" rack
enclosure and I had an SMPS which happened to be Class II, I would be
inclined to leave it in its own plastic case and install it in the rack
enclosure as a "black box" taking care to interface to the existing
inlet and outlet connections and fixing it down with (say) a cable tie
rather than screwing into the case.

If OTOH the SMPS was Class I, I would consider dismantling it and
discarding the case (particularly if I needed the physical headroom). In
this case I might well discard the inlet connector and the outlet cable
and wire to it as if I bought it as an unenclosed product.

Either way, the "whole thing" would be a Class I appliance.

Cheers,
DaveyOz

In article ,
Dave Plowman (News) wrote:

The mains lead twixt 13 amp socket and Buccaneer inlet will be 1mm TRS.
The back of the chassis plug covered by a strong plastic box with a side
exit stuffing gland which the supplied mains lead on the charger will come
out of - a distance of only a few inches. Likely behind the boot carpet -
although that's not yet decided.

While wandering up the highstreet in Canterbury yesterday, I noticed a mobile
police station that had a 240v inlet. Above it was a large sticker describing
all the earthing setup that was required before use.

Would have taken a photo but it was snowing and they appeared busy with a
rather "happy" guy from the pub so I passed them by...

Might be worth a look should you come across something similar

Darren

In article ,
D.M.Chapman dmc@puffin. wrote:
While wandering up the highstreet in Canterbury yesterday, I noticed a
mobile police station that had a 240v inlet. Above it was a large
sticker describing all the earthing setup that was required before use.

Would have taken a photo but it was snowing and they appeared busy with a
rather "happy" guy from the pub so I passed them by...

Might be worth a look should you come across something similar

That sort of thing is likely to have 13 amp etc sockets within it. So
'caravan' type regs would apply. Working in TV, I've seen plenty of trucks
that have 240 volt circuits within them - and it's usual to fit a CU with
full RCD protection. But a bit overkill for what I'm doing.

--
*It is easier to get older than it is to get wiser.

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

On Fri, 18 Dec 2009 09:35:54 +0000, Dave Plowman (News) wrote:
Working in TV, I've seen plenty of trucks
that have 240 volt circuits within them - and it's usual to fit a CU with
full RCD protection. But a bit overkill for what I'm doing.

I dunno, you could have it between the front seats in place of the flux
capacitor :-)

In message
,
" writes

The ciggy socket has to be the type which
is on all the time, which depends upon the car.

I have wondered why that varies between manufacturers.
Worse than that, it varies between models from the same manufacturer.
Bloody stupid idea.
Mine does, and
it's very useful to leave a camera or phone tucked away and on charge
sometimes.


--
Clint Sharp

explained :
On Wed, 16 Dec 2009 11:06:50 -0000, "Vortex4" wrote:


"Dave Plowman (News)" wrote in message
...
I'm thinking of building in one of those Lidl battery chargers in the old
car. So it can be left on float when not in use.
How about "dodgem car" style.

Park one wheel on a metal plate and some kind of ceiling contact. Ground
the plate as well.

I've got no idea how many ohms a tyre would present in circuit...but surely
a small enough figure to trickle charge a battery?

Many many years ago when I had a vehicle with an unreliable battery I
did something like that. Two radio aerials on the car roof one
connected to + other to the body work. Hanging in the garage a couple
of wire coat hangers stuck in a wooden beam and connected to the
charger.
aerials touched hangers and connection made without faffing around
with plugs.

G.harman

To do that the more modern way, you would have the mains connected
primary winding of a transformer hanging from the ceiling at a suitable
height and the secondary winding on the car roof.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield
wibbled on Saturday 19 December 2009 10:24


To do that the more modern way, you would have the mains connected
primary winding of a transformer hanging from the ceiling at a suitable
height and the secondary winding on the car roof.


Then park it round the side of the MI5 building, retreat behind a tree with
a videocam and post on youtube.

--
Tim Watts

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