Over the years and decades the application of scientific knowledge has enabled Sigalarm to greatly improve safety conditions in almost every industry. One particular scientific advancement has been improved understanding of E-Field Strength. E-fields are highly studied, measurable, and documented by science.

Electric Field (E-Field) and the field strength associated with any given E-Field has been a point of misunderstanding throughout governmental agencies and industry for many years.  – Jim Kirkman, November 4, 2016


Electric field is defined as the electric force per unit charge. The direction of the field is taken to be the direction of the force it would exert on a positive test charge. These fields are invisible however detectable by proximity alarms.

The Science Behind E-Field Strength

Kirkman uses what is called Coulomb’s Law to determine the potential for an electrical event. He factors in E-field strength and arrives at a new formula.

Electricity is a dangerous force. E-fields can be simple or complex operators should be trained on E-fields prior to use. The more workers and crane operators know and are trained about how E-fields can be properly used to maintain relative safe distances the better.

E-Field Strength Explained for the Rest of Us

The size and shape of the E-field is dependent upon voltage, configuration, and other factors. For example the field strength of 110 volts at 10ft would be roughly the same as created by 11,000 volts at 100ft. There is a set field strength for every distance from a power line. Simple adjustment of coarse and fine controls on the sigalarm permit accurate and repeatable warnings. Known variables that might affect E-Field detection have been shown over the past 50 years not to be significant enough to cause mass misuse of proximity alarms. The electric field is proportional to the voltage on the line and inversely proportional to distance, (i.e., 1/D) for the power lines. In other words, the closer you get the stronger the electric field gets. This is ideal for detecting the presence of lines.


The potential of an accident can be deeply reduced by maintaining a minimum safe distance from the power line.

Modern Understanding of E-Field Strength Has Improved Greatly

Thankfully science keeps discovering truth. When truth is applied to the workplace, it becomes safer. It’s as simple as that. Decades ago people lacked a complete understanding of electricity and power lines. Sadly, electrocution has taken many lives. But we learn from our past, and the future is bright for safer work environments.

Sigalarm has been on the cutting edge of “safety in the workplace” for half a century and is committed to continuing the advanced work of science to guarantee that for all workers.