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Earth the car?
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. |
Earth the car?
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. |
Earth the car?
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. |
Earth the car?
"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? |
Earth the car?
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 |
Earth the car?
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. |
Earth the car?
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) |
Earth the car?
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. |
Earth the car?
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 |
Earth the car?
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. |
Earth the car?
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. |
Earth the car?
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. |
Earth the car?
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 |
Earth the car?
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. |
Earth the car?
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. |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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. |
Earth the car?
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 :o) -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
Earth the car?
"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 |
Earth the car?
"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 :o) -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk That is because it is not an Audi TT. Adam |
Earth the car?
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... |
Earth the car?
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 |
Earth the car?
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... |
Earth the car?
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. |
Earth the car?
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... |
Earth the car?
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. |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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. |
Earth the car?
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 :-) |
Earth the car?
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 |
Earth the car?
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 |
Earth the car?
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 This space intentionally left blank... |
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