OHM’s Law

Back in the 1980’s, my high school physic teacher taught us about OHM’s law. At that time, I had no idea that 40 years later that I would write an article about the importance of OHM’s with respect to locating on underground facilities.

Without the understanding of OHW’s law, you may struggle in determining the target facility while conducting locates. This battle could lead to mis-locates and the ultimately damages.

OHMs (Ω) are a measure of resistance against an electrical current. The amount of current in a circuit is affected by voltage and resistance.

V is voltage, I represents current, and R is resistance. If you know two of these, you can calculate the other using these equations.

I = V/R

V = I*R

R= V/I

With respect to underground facilities, every facility has inherent resistance factors (material, size and condition) that cannot be improved upon.

The less resistance in a circuit, the easier it is for the current to flow through it; the greater the resistance, the harder it is for the current to flow.

Other resistance factors that cannot be controlled include soil type and facility depth.

You can learn more about OHM’s law and how to overcome resistance and other locating obstacles by enrolling in our Underground Facility Locator Program at www.locatemanagement.com.

Donald Richard, Vice-President, Locate Management Institute