At which point should a voltage tester be placed to check the stop buttons in the circuit?

Placing the voltage tester at the point right after the stop button and ground is the appropriate method for checking the stop buttons in the circuit. This allows you to determine if the stop button is functioning correctly and whether it is allowing voltage to pass through when engaged. If the stop button is open (not engaged), the tester will indicate no voltage, confirming that the stop button is effectively interrupting the circuit as designed.

This method directly measures conditions immediately after the button, providing accurate information on whether the stop button itself is operational. If you place the tester before the stop button, you would not be able to ascertain whether the button is functioning properly because it would show the voltage that is available before interruption. Checking at the power source would also not specify the status of the stop button, as it only confirms the presence of voltage without determining if the stop button can control or interrupt that voltage. Additionally, testing after the motor would not provide any insight into the stop button’s functionality, as any voltage reading there would not reflect the button's condition.