The Purpose of Test and Reset Button on Hair Dryer
Posted by Kmm on Wed, Oct 29th, 2008
There are "test" and "reset" button on hair dryer. When unplug the hair dryer or plug it back in, you have to hit the reset button for it to work. What the purpose of these two buttons are?
The "test" and "reset" buttons are made for GFCI and RCDs. They are safety features!
The GFCI (Ground Fault Circuit Interrupt) is a protection for electric shock (you could see the outlets with similar buttons in the bathroom); and RCDs (Residual Circuit Devices) can test hair dryers to see if they are operational and/or they have been wired correctly.
It is a good idea to check RCDs every month. Just press the button labelled "Test" or "T" on the RCD unit (RCD unit could bypass the ground fault current) and see if the RCD correctly open the circuit. If it does not trip, the RCD should be replaced. Unfortunately, incorrectly wired RCD may still trip when the test button is pressed, even though a real ground fault may not cause it to trip. Use a solenoid voltmeter from live to earth may provide a more effective test of the RCD; such a test should be performed at least once upon installation of the device. The test should be repeated at every outlet "downstream" of the RCD to ensure that the downstream outlets are also wired correctly.
If you dryer fell into water it would automatically shut off and the reset button would pop up. Sometimes Of course, if it overheats, or there is too much current being drawn, or if you have bad wiring it will set off the reset button and shut off too.
The "test" and "reset" buttons are there for safety reasons. However, if you need to hit the reset button regularly then some thing is wrong, you'd better to get a new hair dryer, or there are problems with the outlet or wiring.