A basic understanding of electricity is essential, even for those who do not intend to carry out any repairs or servicing of appliances. Ignorance is no protection against your own or someone else’s errors and oversights, whether with repairs, servicing or installation.
Power is supplied to an electricity substation at a very high voltage — 400,000 volts — in three-phase form. There it is converted, via a transformer, to 230 volt single-phase for distribution to our homes. In normal circumstances, current flows from the live supply of the substation’s transformer, through the electrical appliances used in the house and back via the neutral conductor (cable) to the substation transformer’s neutral pole (a closed loop). Read the rest of this entry »
The earth path of an appliance can be checked easily using a simple test meter. Remember, path of low resistance is required from all items within a appliance that are linked into the earth path via the yellow and green cable.
The earth path of an appliance from its exposed metal parts to the earth pin of the plug should be a maximum of 1 ohm (BS3456).
Checking the earth path of a socket requires an earth loop test meter which needs to be operated correctly. This is an expensive item and, moreover, problems may be encountered with distribution boards fitted with an RCD. It is, therefore, advisable to have these tests done by a qualified electrical contractor. Read the rest of this entry »
When an appliance is in use small sparks are generated at mechanical contacts, such as those found in switches and the junction between motor brushes and commutator. This results in the emission of spurious radio waves that can be heard as crackles on radio or television receivers or that are passed down the mains circuit to audio equipment. The suppressor is designed to eliminate the formation and transmission of these spurious radio waves. They are also known as mains filters. Read the rest of this entry »
