What Would Cause Low Voltage in House Wiring? | Hunker Technically, the definition of "low voltage" is the diminution of electrical current to 90 percent of its normal capacity for a minute or more. The effects of this include poor appliance performance, dim lighting and intermittent outages. Just as serious is the possibility of overheating equipment.. Low Voltage Wired houses! - Electrician Talk Apr 11, 2010I have only worked in one home so far that had low voltage. I was able to diag the problem they were having and thankfully the control panel was accessible. This home had a main panel with 2 sub panels and two low voltage panels. The second low voltage panel i never found but i could hear it clicking above a finished ceiling in the 1st floor.