The mho is a unit of electrical conductance, the reciprocal of the ohm, expressing how readily a material or circuit conducts electric current.
The mho measures conductance, which is the inverse of resistance. Where the ohm quantifies how strongly a material opposes current, the mho quantifies how readily it allows current to flow, with one mho equal to the reciprocal of one ohm. The name itself is ohm spelled backward, reflecting this reciprocal relationship.
Conductance and resistance are two ways of describing the same electrical behavior, and engineers use whichever is more convenient for a given calculation. In the context of conductors, higher conductance means a material carries current more easily, which relates directly to the choice of conductor material and size in cable.
In commercial and industrial systems, the conductive properties of a cable's conductor influence how efficiently it carries current and signal over a run. While resistance is the more commonly cited figure, the concept of conductance expressed in mhos describes the same underlying property from the opposite perspective.
Because conductance and resistance are simply two views of the same property, an engineer can work with whichever is more convenient, and recognizing the mho as the reciprocal of the ohm helps in moving comfortably between the two perspectives.
At Windy City Wire, an understanding of fundamental electrical properties like conductance supports the selection of low-voltage cable with appropriate conductors. Recognizing how conductance relates to resistance helps customers interpret the characteristics that determine how efficiently a cable carries current and signal.
Mho (reciprocal ohm), also called the siemens