Instruments, Fuses and Power Failures

Please think about the voltage equation in a predominantly inductive circuit and the answer will be clear.

Any equipment having sufficient capacity to take the overvoltage (motors ?) or having a surge protection will not fuse else keep your fingers crossed.

Most electrical equipment connected to the single phase power supply (or power grid) (eg-120V, 230V or 240V ac) such as those found in the average home or business, are fitted with in-built spike diverting devices (called MOV = Metal Oxide Varistors, or something similar). Electrical devices fitted with these have a limited ability to withstand the voltage spikes that can occur normally on the single phase power grid. Voltage surges (or overvoltage events lasting more than a few cycles) that can occur due to poor power quality (grid supply voltage regulation issues) can still overwhelm the spike diverting devices however and damage the electrical equipment. If this is the case then the equipment would need to be protected by a more advanced power filter (connected between the electrical product and the single phase power point.

Many modern electrical products (such as televisions, stereos, computers, etc) have an electronic ON/OFF switch (some have both, but the main switch that is commonly used is the electronic one). In these cases, a voltage spike or voltage surge can damage the electrical product even if the electronic switch is in the off position.

The above is just a really general overview. Can you please provide more information regarding what your question is. When you write "risk of getting fuse when its in ON condition", this indicates to me that you are witnessing internal fuses operate (commonly referred to "open-circuiting", "blowing" or "fusing"). If this is the case then it is likely due to inrush currents due to voltage surges. The MOV devices mentioned above are commonly placed after the fuse and as they divert the voltage spike or surge (either to ground or to neutral) they effectively act as a short circuit (hence potentially causing the fuse operate). Devices with a large inductance (such as motors) can also cause fuses to operate.

I hope I haven't confused you too much.

right one....thanks dear