i thank everybody for helping me with the cable length problem faced in designing the water level controller ...
i need to incorporate Low and High Voltage (Supply 230V) Protection to the device ....
Specifications:
1. It should be automatic and should cut-off the power supply to the main circuit if the voltage
a. Falls below set value (say 180V)
b. Goes above a set value (say 260V)
and resume once the voltage returns in the normal working range.

Work Around:
Method 1:

have a comparator which keeps monitoring the o/p Voltage of the transformer (secondary coil) and in case it falls below a certain level or goes beyond a level, switch off a relay which provides supply to the main circuit. But i dont want to use an OP-AMP for it ... may be a potential divider circuit or some diodes in series and a transistor might detect the low voltage ... not sure though ... but what about the high voltage part???


Wish to cut the supply off to the primary of the transformer .... if possible ...but dont know how it can be done ....

please suggest some nice and cheap solution for this problem ...

Thanks a lot in advance ....
nitin