Electrical Tutorials -Safe Electricity Without a Ground

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Re:

Postby jazzman » Sat Feb 07, 2009 4:17 pm

rigpig.sparky wrote:What's black and crisp and hangs off the ceiling ?

The Limey?

Everything you need to ELECTRIFY your house - and not yourself !

How to calculate your power supply needs
How to build a $20,000 / £14,000 house and a $???? MOTEL Updated 21 March 09 - with BOQ and costs
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby crossy » Fri Mar 13, 2009 4:45 pm

To answer the query about tingly PCs. What you are feeling is the leakage through the mains-inlet filter, THIS IS NOT A FAULT it is a design fact. The filter needs a ground to operate properly although you may reduce the tickle by reversing the supply plug.

The filter capacitors form a potential divider so that the casework floats around half mains voltage, this leakage, whilst you will feel it is unlikely to kill. A half reasonable ground will kill it dead.


Any equipment with a metal casework that is not double-insulated MUST have a ground even if protected by an RCD / RCCB / ELCB / GFI / Saf-T-Cut (all the same thing). Should you get a live to casework fault and the internal leakage is insufficient to drop the ELCB then the metalwork is live and will give you a nasty shock, hopefully the ELCB will drop out before you die!

It is perfectly possible to have a safe system with no ground provided no equipment that needs a ground is connected. It is not possible to have a safe system with no ground when equipment that requires a ground is included, this way lies danger :(
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby jazzman » Fri Mar 13, 2009 4:52 pm

This interesting Crossy, because aluminium cased Macintosh laptops are notorious for giving their owners an uncomfortable buzz, although the main connection comes through a separate mains transformer with a two-pin plug only.
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby crossy » Fri Mar 13, 2009 6:24 pm

jazzman wrote:This interesting Crossy, because aluminium cased Macintosh laptops are notorious for giving their owners an uncomfortable buzz, although the main connection comes through a separate mains transformer with a two-pin plug only.

Yeah, I heard about those too, and never found a satisfactory explanation. I can't believe Apple would foul up their PSU design badly enough to cause shocks, then again, bet it was outsourced :(
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby rigpig.sparky » Fri Mar 13, 2009 6:53 pm

I don't believe it is just Apple, I wonder if the power cord is the wrong one and it should be a 3 pin. If it is a seperate lead that plugs into the power supply it would be a possibility. Maybe the power supply inlet has an earth position. You are right about desk top computers needing a ground though cossy it is part of the design, its how it gets rid of the transient voltages and keeps the supply constant and in a certain range.
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby crossy » Fri Mar 13, 2009 7:23 pm

My old Dell laptop has a 3 pin mains lead to the PSU block, then a 2 pole connector to the PC. It often gets plugged into un-grounded outlets ('coz that's what's available).

I have two PSUs, one the original OEM supply which gives no problem if un-grounded. The other a 'pattern' unit (still says DELL on top) bites HARD if run un-grounded.
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby jazzman » Sat Mar 14, 2009 11:58 am

I don't know anything about PCs but my wife complains of a buzz from the case of her PC which is earthed..
All Macintosh laptop computers are supplied with an Apple proprietary mains transformer that has a 2-pin connection only. Power packs for the UK market ship with a mouled, fused 3-flat-pin plug, but there is no earth core in the mains lead. I am not specialised in electronics, but I would think that the buzz comes from some high amperage from the 16V internal electrics or from a capaitor. However, there is no buzz when running off the battery without the mans lead connected.

Maybe this has something to do with with reversed olarities in the 2-pin mains sockets where several peripherals with indipendent power supplies are connected together through powered FireWire and/or USB hubs, and UPS units.
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Re: Pictures, Prices and Amperages

Postby nanbuilder » Mon Aug 22, 2011 8:37 am

jazzman wrote:There are now pictures, prices, and where to buy these Minature Circuit Breakers, their housing and the RCBO (Residual Current Detector/Breaker, aka Earth leakage Breaker) on this thread - together with everything else you need to equip a house, with up-to-date prices:

http://coolthaihouse.com/cthpics/thumbnails.php?album=10

Contrary to common belief, this equipment is NOT expensive at all, nowhere near the GBP 100.00 cited - not even half that :!:


Hi Jazzman, many thanks for posting all the great pics. Can I please ask you to review this one:
http://coolthaihouse.com/cthpics/displa ... fullsize=1
is this the type you would recommend for my Homestay Chalet? If yes, confirm this is for a two wire electrical installation only?
The Homestay Chalet anticipated electrical requirement is:
small aircon split unit with compressor (12sqm bedroom);
hotwater shower unit 3500 watts;
refrigerator;
microwave;
tv + SAT;
internet router;
minimal lighting;
fan;
laptop.

I understand the shower unit should be independently earthed to an external ground earth spike.

Do I need to install a separate breaker for the wall shower unit? or can it be connected to the consumer unit? Likewise the AC, does this need a separate breaker. It seems Thai standard is to always install a breaker unit such as the one below for any new shower or air conditioner installations that I have ever had in the past - is this really necessary if I have the consumer unit described by Jazzman in the link above and all the wiring is in place as part of the sparky installation??. Thanks.
DSC04367.jpg
Thai Breaker Box - seems bog standard for every installation of a shower or AC
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby Roger Ramjet » Mon Aug 22, 2011 9:48 am

nanbuilder,
I totally agree with your questions. I asked the same or similar questions a number of times but all I got in reply was platitudes about British standards, Australian standards and American standards, which I found to be most unhelpful because I live in Thailand.
So I did what you have done, I talked to people and researched Thai websites on Thai standards. I also looked at the number of people killed from electrocution in Thailand, which happened to be as low as anywhere in the world. I also asked the question if a person was a qualified "sparky" in their home country or if they were reiterating the "party line" in what their "regulations" said.
Of course, except for the excellent tutorials here, posted by real qualified "sparky's" I couldn't get an answer, just guesses, or at best other countries regulations which do not apply in Thailand .
I too, after fruitless discussion into how RCBO's and breakers are not satisfactory as per other countries regulations, went out and bought two Safe-T-Cut boxes with ten circuit breakers in each and an RCBO tester installed in the unit. (There are photos posted somewhere here of both these). And I can post more photos if you so wish it, as the two units are still in my townhouse.
And then the fruitless indignant discussion about earthing all the pipes, and the sink, aircons, heaters and etc etc etc, when all the pipes are PVC anyway. And how I should have an earth... but where to put it when you live in a townhouse surrounded by concrete? And of course where to put the earth poles when the ground is baked hard.
When I bought the Safe-T-Cuts I did after careful research....in Thailand, not England or any other country. The company must have the utmost confidence in their product, because two weeks after I bought them they sent me two insurance policies for free, that covered electrocution, fire and other instances involving their boards.
I have an RCBO Safe-T-Cut here at the townhouse at the moment and it trips properly when the circuit is overloaded. It is also tested every 6 months. If I get electrocuted now, at least I know my wife will be well off in the future because each policy was for 1,000,000 baht.
Good luck with the questions, just ask when you get replies, if they are a qualified "sparky" or not; like the people who posted the excellent tutorials both are.
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby nanbuilder » Wed Aug 24, 2011 5:54 pm

Roger Ramjet wrote:nanbuilder,
I totally agree with your questions. I asked the same or similar questions a number of times but all I got in reply was platitudes about British standards, Australian standards and American standards, which I found to be most unhelpful because I live in Thailand.
So I did what you have done, I talked to people and researched Thai websites on Thai standards. I also looked at the number of people killed from electrocution in Thailand, which happened to be as low as anywhere in the world. I also asked the question if a person was a qualified "sparky" in their home country or if they were reiterating the "party line" in what their "regulations" said.
Of course, except for the excellent tutorials here, posted by real qualified "sparky's" I couldn't get an answer, just guesses, or at best other countries regulations which do not apply in Thailand .
I too, after fruitless discussion into how RCBO's and breakers are not satisfactory as per other countries regulations, went out and bought two Safe-T-Cut boxes with ten circuit breakers in each and an RCBO tester installed in the unit. (There are photos posted somewhere here of both these). And I can post more photos if you so wish it, as the two units are still in my townhouse.
And then the fruitless indignant discussion about earthing all the pipes, and the sink, aircons, heaters and etc etc etc, when all the pipes are PVC anyway. And how I should have an earth... but where to put it when you live in a townhouse surrounded by concrete? And of course where to put the earth poles when the ground is baked hard.
When I bought the Safe-T-Cuts I did after careful research....in Thailand, not England or any other country. The company must have the utmost confidence in their product, because two weeks after I bought them they sent me two insurance policies for free, that covered electrocution, fire and other instances involving their boards.
I have an RCBO Safe-T-Cut here at the townhouse at the moment and it trips properly when the circuit is overloaded. It is also tested every 6 months. If I get electrocuted now, at least I know my wife will be well off in the future because each policy was for 1,000,000 baht.
Good luck with the questions, just ask when you get replies, if they are a qualified "sparky" or not; like the people who posted the excellent tutorials both are.


Hi Roger, many thanks for taking the time to respond; I guess the tutorials give all the information..... I guess it was the amount of dis-information that made me want to double check! Yes, please do post the extra pictures of the Safe T cuts so that I can see your set up. As (I think) you suspected there are no further responses on the subject, so I am going to post final solution to my build thread in due course, and see if that sparks any further comment (excuse the pun). For completeness here I will buy for the chalet 15 amp supply something similar to this:
consumer unit T.jpg

my intention is:
one 15amp cct for the electric shower 3500 watts
one 15 amp cct for the air con
one 10 amp cct for the power sockets
one 10 amp cct for the lights
I intend to provide one single separate earth for the shower unit running to an external earth spike
I intend to install a lighting rod - will it be safe to utilise the same earth spike in the ground for this?
I am not intending to install additional separate obtrusive breakers for the shower or air con - please tell me if I am missing something here.
I will not be earthing the PVC pipes :wink:
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby Roger Ramjet » Thu Aug 25, 2011 6:46 am

nanbuilder,
Here's the board.
Attachments
10 switch unit with RCBO.jpg
10 switch RCBO unit board
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby Roger Ramjet » Thu Aug 25, 2011 7:47 am

nanbuilder,
The question you asked about using the earth spike and the lightning rod, as one, is not possible as they are two different identities and do two different things. The earth rod is for surges of 240 volt power when there is a fault IE bad wiring. The RCBO unit is there for that and you can also add an earth rod/spike into a wet area (it has to be wet the whole time or it won't work).
The lightning rod is for lightning strikes and will carry huge amounts of electricity (it is said that one lightning strike would power a large city for a week) to the ground where it dissipates in theory. If the area is wet where the lightening rod goes into the ground and the surrounding ground is also wet the whole area will be live. If it is dry, then it won't work (Richard Bramston's mansion is proof of that) and the house will take the huge electrical current.
There are a number of ways to do it "properly", but each one I've read about says to do it a different way. Just type in lightning strike in Google and the mind boggles.
I posted what I had found on Max's thread a few days back, when Max asked a similar question.
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby nanbuilder » Thu Aug 25, 2011 8:10 am

Roger Ramjet wrote:nanbuilder,
The question you asked about using the earth spike and the lightning rod, as one, is not possible as they are two different identities and do two different things. The earth rod is for surges of 240 volt power when there is a fault IE bad wiring. The RCBO unit is there for that and you can also add an earth rod/spike into a wet area (it has to be wet the whole time or it won't work).
The lightning rod is for lightning strikes and will carry huge amounts of electricity (it is said that one lightning strike would power a large city for a week) to the ground where it dissipates in theory. If the area is wet where the lightening rod goes into the ground and the surrounding ground is also wet the whole area will be live. If it is dry, then it won't work (Richard Bramston's mansion is proof of that) and the house will take the huge electrical current.
There are a number of ways to do it "properly", but each one I've read about says to do it a different way. Just type in lightning strike in Google and the mind boggles.
I posted what I had found on Max's thread a few days back, when Max asked a similar question.

Thanks Roger - I see now lightning rods are not straight forward at all. I will put an independent earth spike in for the shower and plan separately for lightning strikes after I have learnt much more on the subject. Incredibly helpful - many thanks.
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby Roger Ramjet » Thu Aug 25, 2011 8:47 am

nanbuilder,
This is what you are up against: http://www.weatherimagery.com/blog/can- ... -my-house/ I found the explanation to be really helpful along with the photos and links. I'd say the same happened to Richard Branson's mansion, except his caught fire.
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Re: Electrical Tutorials -Safe Electricity Without a Ground

Postby nanbuilder » Fri Aug 26, 2011 8:23 am

nanbuilder wrote:
Hi Roger, many thanks for taking the time to respond; I guess the tutorials give all the information..... I guess it was the amount of dis-information that made me want to double check! Yes, please do post the extra pictures of the Safe T cuts so that I can see your set up. As (I think) you suspected there are no further responses on the subject, so I am going to post final solution to my build thread in due course, and see if that sparks any further comment (excuse the pun). For completeness here I will buy for the chalet 15 amp supply something similar to this:
The attachment consumer unit T.jpg is no longer available

my intention is:
one 15amp cct for the electric shower 3500 watts
one 15 amp cct for the air con
one 10 amp cct for the power sockets
one 10 amp cct for the lights
I intend to provide one single separate earth for the shower unit running to an external earth spike
I intend to install a lighting rod - will it be safe to utilise the same earth spike in the ground for this?
I am not intending to install additional separate obtrusive breakers for the shower or air con - please tell me if I am missing something here.
I will not be earthing the PVC pipes :wink:


Quick update. My builders merchant, after seeing the sketch plan for the chalet, tells me an RCBO is a waste of money! Additionally the 4 'breakers' should (in his opinion) be 2x 32amp and 2x15amp. To be clear the electric supply is single phase. I am no sparky, but to me he is over-rating the amperage for the appliances to be connected (listed above), and no RCBO brings us back to the 'no earth' argument and debate. Maybe he (the builders merchant) should stick to roof tiles and cement on the advice front? Yours truly, confused from Nan!

IMG_5992.JPG
Our meter and supply will be exactly like this
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