How the First Electric Wires Were Dangerously Uninsulated


The invention of the electric telegraph in the 1830s was a major breakthrough in communication technology. For the first time, messages could be transmitted over long distances almost instantly using electricity flowing through wires. However, early telegraph systems had a major flaw - the wires themselves were completely uninsulated. This led to systems that were prone to failure, fires, and even electrocution.

The First Telegraph Systems

The telegraph was developed independently by several inventors in the 1830s, including Samuel Morse in the United States and Charles Wheatstone in the United Kingdom. They strung up wires on poles and sent pulses of current through the lines to spell out messages in Morse code at the receiving end. However, these early telegraph lines used bare, uninsulated copper wires.

This was dangerous for a few reasons:

Fires and Other Damage

The uninsulated wires also caused fires on numerous occasions when lines swung together in the wind. The short circuit would generate sparks hot enough to ignite nearby material. Fires destroyed telegraph offices and entire city blocks over the years.

Bare wires also caused problems when trees or branches fell across telegraph lines. The wires were easily broken, cutting off communications until the line could be repaired.

Dangers to Telegraph Workers

Working with live uninsulated wires was exceptionally dangerous. Telegraph operators had to be constantly vigilant not to contact the bare wires inside offices and while making repairs on pole lines.

However, accidents still happened regularly. Many telegraph workers suffered painful shocks, burns, and even death from the primitive uninsulated telegraph systems. Fatalities were unfortunately common.

Notable Incidents

Some of the notable cases of telegraph workers killed by uninsulated wires:

The Push for Insulated Wires

It soon became clear to many that insulating telegraph wires was critically necessary to prevent fires, interruptions, and fatalities. However, it took decades for insulated telegraph and power lines to be widely adopted.

Early Insulation Methods

Some early efforts were made to try insulating wires, including wrapping them in fabrics, coating them in wax and pitch, and running them through wood moldings. However, these methods provided poor insulation and were not durable when exposed to the elements.

Telegraph Linemen Resist

Ironically, some telegraph linemen resisted the push for insulated wires, seeing it as a threat to their profession. They felt that it minimized the need for telegraph repairmen to keep lines working. This attitude kept telegraph companies from upgrading their lines.

Edison's Breakthrough

Thomas Edison pioneered a cotton and linen insulation coated in rubber that provided excellent insulation without degrading outdoors. This was used for underground lines and became standard as central power systems grew in the 1880s and 90s.


The first electric telegraph systems revolutionized long-distance communications. But the dangers of uninsulated wires cost many lives through electrocution, fires, and accidents before effective insulation was widely adopted. Insulated wire seems obvious today, but was an astonishing breakthrough in its time. The introduction of reliable insulated wires helped pave the way for the modern electrified world.