I have a air humidifier connected to a timer, and every time it turns off there is a huge spike going through the lines; lamps and computer monitors flicker.
I'm thinking about buying a surge protector to put in front of the perpetrator, will this prevent it from sending out spikes? Or do they only protect again incoming spikes?
Best Answer
Most ordinary surge protectors are designed to protect against large incoming surges only. That is surges large enough to cause permanent damage to equipment. They are not intended to prevent mere flickering of lights.
Many (maybe most) of them provide only one-time protection against large surges (e.g. lightning strikes nearby)
It is very unlikely that a typical home/office surge protector will provide the benefit you seek.
The relevant Wikipedia article says:
Other types of protective device can be more durable, but they still might not prevent lights from flickering.