Electrical – Why are homes wired using solid wire rather than stranded

electrical

If stranded wire can carry more power for a given wire gauge, why are homes typically wired using solid?

If solid wire is less expensive to make, that provides a compelling reason why solid is used, but if an electrician or homeowner wanted to use stranded, is there any reason not to?

For this question I am mainly referring to legs of U.S. home wiring for 15 and 20 amp breakers carrying 120 volts on a single phase.

Best Answer

A few reasons:

  • Stranded wire is more expensive to make.
  • At a given wire gauge, stranded is going to be larger than solid wire (it's the cross-sectional area of conductor that counts and there are going to be some air gaps between conductors with stranded). This could make a big difference if you have several cables in a limited space like an electrical box.
  • The main advantage of stranded is that it's more flexible. You generally don't need this in home wiring because it's all put in place once and hidden behind walls/floors/ceilings.
  • When you screw a solid wire into a switch or receptacle, you can tell if it's secure. I could see individual strands coming loose as you fold wires back into an electrical box.

More information in Wikipedia: http://en.wikipedia.org/wiki/Wire#Solid_versus_stranded

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