Fred down the pub said that I can save money by not using a qualified sparks to test my R.C.Ds. He said that I can make my own R.C.D. tester. Is it safe?
The test button on some designs of RCD does provide an audio-visual indication if the contact opening time is too long, by getting the test resistor so hot so that it fails with a load bang. ..
In such cases ,the test lamp maybe preferable.
Beware of the resistance of filament lamps being highly non-linear - when cold they take about 10 times the hot current - i.e. the rated wattage.
This is of particular significance to designers of lamp dimmers, where the current and voltage are not in the expected ratio for a simple resistance.
The test button on some designs of RCD does provide an audio-visual indication if the contact opening time is too long, by getting the test resistor so hot so that it fails with a load bang. ..
In such cases ,the test lamp maybe preferable.
Beware of the resistance of filament lamps being highly non-linear - when cold they take about 10 times the hot current - i.e. the rated wattage.
This is of particular significance to designers of lamp dimmers, where the current and voltage are not in the expected ratio for a simple resistance.
