Why is it necessary to have an earth wire installed in a power circuit, but not in a lighting circuit ?
Why is it necessary to have an earth wire installed in a power circuit, but not in a lighting circuit ?
Lighting circuit wiring usually goes through or over walls through insulated tracks. Switches used to control wiring are also fully insulated. The fittings are properly isolated and insulated from surrounding walls, and are made of materials not affected by weather. So there is no need for earthing.
shock.Mostly lighting appliances such as tube lights and all are made of glass which is bad conductor of electricity so if we touched tube light we will not get a shock.
However, plugs used in lighting circuit are used for connecting table fan, table lights, decoration light etc bodies of which can come in touch with a person. Earthing is necessary and is used for these. A plug is commonly provided on such plug outlet everywhere.
Power circuits are invariably used for heavy loads like stove, coolers, ovens, machinery, appliances, pumps etc which are commonly handled by people. Earthing is very much necessary in these circuits as protection of personnel as also the machinery itself in case of fault or failure of insulation due to any reason. Heavy current due to overload on equipment also be a cause of such failure, as also ageing of equipment leading to insulation breakdown.
In case of high power circuits, like your microwave, the body is metal and hence it has to be earthed to prevent conduction by the body so that it doesn't harm the user when they touch it.
Lighting circuit wiring usually goes through or over walls through insulated tracks. Switches used to control wiring are also fully insulated. The fittings are properly isolated and insulated from surrounding walls, and are made of materials not affected by weather. So there is no need for earthing.
shock.Mostly lighting appliances such as tube lights and all are made of glass which is bad conductor of electricity so if we touched tube light we will not get a shock.
However, plugs used in lighting circuit are used for connecting table fan, table lights, decoration light etc bodies of which can come in touch with a person. Earthing is necessary and is used for these. A plug is commonly provided on such plug outlet everywhere.
Power circuits are invariably used for heavy loads like stove, coolers, ovens, machinery, appliances, pumps etc which are commonly handled by people. Earthing is very much necessary in these circuits as protection of personnel as also the machinery itself in case of fault or failure of insulation due to any reason. Heavy current due to overload on equipment also be a cause of such failure, as also ageing of equipment leading to insulation breakdown.
In case of high power circuits, like your microwave, the body is metal and hence it has to be earthed to prevent conduction by the body so that it doesn't harm the user when they touch it.
