i am planing to design smart sockets whether it is possible with arduino?? my Main aim is that protect overload,neutral line fault,overheating protection so i am plan to use relay,temperature sensor,zigbee,and LEDs which are controlled by arduino
is that possible one ?? 
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What kind of sockets?
home sockets....
It is possible, but there are substantial hazards involved in designing circuits using high voltages and electronics - the fact you're asking whether it's possible makes me suspect that you aren't trained or qualified to deal with these hazards, in which case I recommend you stay clear of them.
My question is whether One board is enough to control all these things?? (temperature sensors,relay,zigbee,LEDs and power measurement) can i use shift registers ?? 
Yes, a single '328P based board with 20 IO can do all that.
If you overload the mains socket, the fuse in front of it will blow. So, that part you already have covered.
The socket will not overheat. The fuse will (or at least should) blow long before that. Furthermore, no household appliance should draw that much current, ever. If it does, something's horribly wrong.
Fault on neutral line? Does that happen often in your household?
In india the household wiring is not that much efficient more loose contacts so inside wiring are burning i have saw so many case who died in water heater... so in india is poor household wiring thats why i am planing to design such a work even in my home it happened inside the sockets the wire are burnt but it didnt trip off the circuit... between its just my idea to design home automation eh implementing so i am just trying to do efficient household wiring so pls help me guys...
this is my plan guys.... need some suggestion and guidance from u... and give me an ideas to implement with in 3 weeks plzz ...
see the image ... help me out :~
help me out
Help you with what? Your project sounds a lot like "Get someone else to build the hardware and write the software". For that, we expect to get paid. Reviewing your work we do for free.
i want to know how to transmit the power measurement and faulty data into zigbee and which transmit to the LCD screen....
... and on the other thread, you want somebody to design the hardware for you. This doesn't seem like a request for help with a problem - more like a very ambitious project taken on (I suspect it's for academic credit since you seem to have a pretty tight deadline imposed) which you are nowhere near implementing and want people to implement for you.
yup frnd within 2 weeks i have to finish it thats y btw if i trouble u sorry... i need guidance and help thats y asked....
Given the scope of the problem you're tackling and the lack of progress implied by your questions, I suggest it would be a good idea to let your tutor know what your situation is. Unless you find somebody willing to do the project for you, which you're not likely to do on this forum, you're setting yourself up to fail. There may still be time to reset expectations and identify a project you can complete in the time available.
