Drop

• The Pennsylvania College of Technology (PCT) reports a small voltage drop is expected to occur on any electrical circuit at the farthest point of the circuit. A small drop between one and five percent is reasonably expected, with large voltage drops resulting in heating of wires leading to a risk of electrical fire.
  
  

Causes

• There are number of reasons the voltage of an electrical outlet could be lower than expected. These reasons include large lengths of wire in a circuit, corroded wires and components and a wire size that is too small for the electrical load passing through it.
  
  

Size

• According to House Inspections, the five percent drop in electrical voltage allowed by the National Electrical Code is a recommendation rather than a required part of the code. Some home inspections allow a drop of between eight and ten percent, which shows no risk of a fire hazard.