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Each room here is wired in a ring, Earth, live and Neutral arrive at the first socket, are wired to the next socket and at the end of the ring all three return to the fuse box where they are wired in parallel with the first wires. It means there are two paths for current to flow (two directions around the loop) which gives half the resistance and better protection if a break occurs. Part of the statutory electrical inspection is to break the loop and measure the resistance around it to confirm connectivity. For a single room with (in my case) 8 outlets, the live and neutral are 2.5mm2 solid copper. the Earth wire is slightly thinner, I would guess 1.5mm and the trip rating is 32A. I have 'real' Earth points to 1m long copper rods at each side of the house as well as the connection back to the transformer. The long pin on the 13A rated UK sockets is the Earth pin, the extra length ensures it connects before live and neutral and it also opens a shutter mechanism in the sockets that otherwise closes off the holes for live and neutral.Q: Do you have a ring feed in your home/apartment? What is the purpose of middle contact (longer one) on UK type mains plug?
Yep that's a big possibility in our district power distribution, I took these photos just now.Neutral and Earth are usually bonded together but not at the socket, it is done back at the distribution transformer where both have a real 'planet Earth' ground.
If you bond them at the socket and a fault occurs, the earth pin could become live and hence extremely dangerous. Consider what would happen if the neutral connection back to the box went open circuit, your PC would stop working but the case would be at 230V AC!
Each room here is wired in a ring, Earth, live and Neutral arrive at the first socket, are wired to the next socket and at the end of the ring all three return to the fuse box where they are wired in parallel with the first wires. It means there are two paths for current to flow (two directions around the loop) which gives half the resistance and better protection if a break occurs.
Part of the statutory electrical inspection is to break the loop and measure the resistance around it to confirm connectivity. For a single room with (in my case) 8 outlets, the live and neutral are 2.5mm2 solid copper. the Earth wire is slightly thinner, I would guess 1.5mm and the trip rating is 32A. I have 'real' Earth points to 1m long copper rods at each side of the house as well as the connection back to the transformer. The long pin on the 13A rated UK sockets is the Earth pin, the extra length ensures it connects before live and neutral and it also opens a shutter mechanism in the sockets that otherwise closes off the holes for live and neutral.
I do actually have a 125A 3-phase mains supply here but it is unusual in the UK and I only use one phase and neutral within the house. In most places the neutral and rotating phase connections are outside the property at the buried distribution cable.
It's a long story but basically, the cable carries on beyond my house to a three-phase motor on a waste treatment plant nearby. The cables used to be overhead but trees fell across the wires and shorted them together - you can imagine what happens when the output of a transformer similar to the one you showed gets shorted out! I had to install my own underground cable about 150m to the transformer and it still had to be 3-phase so the motor would remain in operation. So I installed a fat 4-core, each 25mm2 armored cable (3 phases, neutral and an earth shield) to my house where I only connect to one phase and neutral but a smaller cable continues on to the waste plant motor.Did you have this 125A 3-phase mains supply for extra money from electricity company ? Is it the main electricity source for your house ?
Electrical safety standards are basically international. Only some implementation details are specific in particular countries, e.g. current rating of sockets, switches or fuses required for sockets. But the points discussed here are universal. I reviewed some publications form Saudia Arabia and they all seem to refer to recent international safety standards.
Earthing systems accepted for domestic power distribution are TN-S or TN-C-S (mostly used), also TT in combination with RCD (residual current device) if local earth has too high impedance.
TN-C (common wire for earth and neutral is only accepted for industrial installations with PEN wire cross section >= 10 mm².
https://en.wikipedia.org/wiki/Earthing_system
wow that's really scary ! you're lucky it didn't burn your garden or the green around you, as you are in UK so there are a lot of treesIt's a long story but basically, the cable carries on beyond my house to a three-phase motor on a waste treatment plant nearby. The cables used to be overhead but trees fell across the wires and shorted them together - you can imagine what happens when the output of a transformer similar to the one you showed gets shorted out!
I had to install my own underground cable about 150m to the transformer and it still had to be 3-phase so the motor would remain in operation.
So I installed a fat 4-core, each 25mm2 armored cable (3 phases, neutral and an earth shield) to my house where I only connect to one phase and neutral but a smaller cable continues on to the waste plant motor.
It was expensive and a lot of work but it keeps the lights on!
Brian.
I called the electricity company booked a ticket, they called me back. And I asked them if the mains is grounded and he told me that the outer lines ground is different then what I have inside the apartment !!! How come ? If the outer is grounded then what I have is grounded !!
I asked him again and he repeated the same information !! There's no another transformer between the distribution room and the building !!
What does this mean? As far as we have seen, there's no grounding in your apartment panel. No ground wire available, no grounding of sockets.
The utility company isn't responsible for safe installation inside your house, it's the house owner.
We can expect the neutral is grounded at the distribution transformer, and it's most likely also grounded at the house distribution panel.
Eagle1109, do you have any idea what or where the gray wires go to. They look like they pass through the box without connecting to anything.
I guess it's CATV or telephone.
Of course these voltages are the reason for 110V voltage on the chassis.
This alone would make me move out of that apartment and find another where the owner doesn't want their tenants to get electrocuted by 230V.Yep, that's right. I called the owner and he told me that he didn't install a ground to the building.
You are suggesting the wrong person should do this. The OP should ask the owner to do this. If the owner survives then they can ask for reduced rent due to a hazardous living conditions. If the owner doesn't survive well it serves them right for leaving off the ground connection. ;-)Until you install proper grounding you will feel electric shocks.
Wet your bathroom floor, stand on it barefoot and touch your PC when switched on.
If you survive, please describe the feel(DO NOT DO THIS!!!)
This alone would make me move out of that apartment and find another where the owner doesn't want their tenants to get electrocuted by 230V.
You are suggesting the wrong person should do this. The OP should ask the owner to do this. If the owner survives then they can ask for reduced rent due to a hazardous living conditions. If the owner doesn't survive well it serves them right for leaving off the ground connection. ;-)
You are absolutely right about "tester"
If he does not survive, anyway will be "grounded"
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