riscado wrote:Hi thanks for all the replies, still reading them through and digesting ideas...
By the way I'm in portugal - europe, and the power suply is 230V - 50hz (although I get readings closer to 238V)
Well then, none of the code that I've referred to applies at all!! Sorry. I was not even aware that electrical systems in the EU ever provided a grounding conductor. And now that I know that they do, I wonder why.
In any case, you need to quietly ask a local electrician for advice. I suspect that he/she will suggest you pick up a local water pipe connection and use that. Just as has been suggested early on in the thread. Don't be messing with grounding one of your circuit conductors.
The Last of the World's Great Human Beings
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
You can connect protective earth ("ground") to the garaghe water pipe if there is one. It MUST be connected through a ground fault circuit breaker.
and try and see how it works, I believe it will do nicely...
Skyboltone, I didn't really understand why it comes as a surprise that electrical installations in the european union use a grounding conductor, besides they've been doing so for quite some time now!
As a previous poster pointed out, the GFI will only work if neutral is connected to earth ground somewhere. Once you get your ground connection, measure the voltage from both sides of your mains circuit with respect to ground, and make sure one side measures really close to zero.
riscado wrote:Hi, I'm going to use VaccumVoodoo's info:
You can connect protective earth ("ground") to the garaghe water pipe if there is one. It MUST be connected through a ground fault circuit breaker.
and try and see how it works, I believe it will do nicely...
Skyboltone, I didn't really understand why it comes as a surprise that electrical installations in the european union use a grounding conductor, besides they've been doing so for quite some time now!
There was no sense there of the EU system being primative or not up to US standards. My puzzlement is that I thought that neither side of the EU system is grounded at the transformer. The debate comes up all the time amongst US inspectors on who got it right, us or the European engineers who designed the system. There is strong support for ungrounded systems. US engineers claim that grounding one circuit conductor at the source of supply creates a direct path for fault current in the event that the "hot" wire goes to a chassis or metal structural part somewhere. As I understand it, in Europe, both circuit conductors are isolated from ground, so fault currents will only flow from one conductor and return via the other. A "short" to ground does not exist. So my puzzlement is why ground anything if not for fault currents? I may well not understand how European distribution systems work. As Alex said, you folks use some sort of GFCI which presumably compares the current on one leg to that of the other and trips if they are not more or less equal. What I don't understand is, if neither conductor is grounded at the source, what path would the fault current take back to the source of supply?
Dan
The Last of the World's Great Human Beings
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
We definitely have our neutral connector (cold) tied to ground in European systems, at the local substation (transformer) or before the main supply fuse when entering a premises. It varies slightly from country to country. It's certainly not on the consumer side of the supply in the property, and would be illegal to do so in the UK.
We've also always had polarised connectors in the UK, and why some European countries (notably France and Belgium) have changed to a modified Schuko connector with an offset ground pin to force the polarity being known.
The only time I'm aware of 'floating' both conductors is on construction sites where, certainly in the UK, only 110V tools are permitted. We use an isolation transformer and tie the centre-tap of the output winding to ground to give a +/- 55Vac supply to the tools. The idea being that you are likely to get shocked with only 55V unless you are really unlucky.
I'm still stunned that this premises in Portugal doesn't have a ground. I can't imagine how long ago that practice would have been outlawed.
Hi, it is outlawed, unfortunately some contractors simply choose not to ground garage or basement installations, even though they do the proper installation for the rest of the building... most inspectors seem to close their eyes once some money has been misteriously dropped on their pocket
We definitely have our neutral connector (cold) tied to ground in European systems, at the local substation (transformer) or before the main supply fuse when entering a premises. It varies slightly from country to country. It's certainly not on the consumer side of the supply in the property, and would be illegal to do so in the UK.
We've also always had polarised connectors in the UK, and why some European countries (notably France and Belgium) have changed to a modified Schuko connector with an offset ground pin to force the polarity being known.
The only time I'm aware of 'floating' both conductors is on construction sites where, certainly in the UK, only 110V tools are permitted. We use an isolation transformer and tie the centre-tap of the output winding to ground to give a +/- 55Vac supply to the tools. The idea being that you are likely to get shocked with only 55V unless you are really unlucky.
I'm still stunned that this premises in Portugal doesn't have a ground. I can't imagine how long ago that practice would have been outlawed.
Paul
Well now it all makes sense. I (and a great many other US inspectors) have been misinformed. Our code reads with respect to the grounded conductor (from memory) "The grounded conductor shall be bonded to the grounding electrode conductor at any convienient point between the service entrance and the first overcurrent protective device". The code goes on to explain what constitutes a grounding electrode (water pipe, ground rod, ground ring, etc. etc. and how these are to be tied together at the premises) and the grounding electrode conductor. Your Wikipedia article shows only "star" or "wye" connected services (not Delta) and uses the initials PE (protective earth) for the US "grounding conductor". Anyway, mystery solved.
Riscado, you have made the correct choice provided, as I said, that you ensure that the water pipe that you make your grounding conductor attachment to is bonded at the main service, and that you don't as Paulster notes make a solid connection between your grounded conductor (N) and this newly established PE.
Thanks All
Dan
The Last of the World's Great Human Beings
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
So basically I'll have to connect the ground connection (green/yellow) of the mains to the pipe... And the neutral (blue) wire should not be in contact with this ground.
Exactly. So long as your pipe is metal and goes into ground, or is bonded to ground elsewhere.
And add in an RCD (residual current device) for good measure which is a current transformer looking for any imbalance between the live and neutral connectors (i.e. current flowing to ground) and you should be pretty safe.
