In looking at a 1915 catalogue of Electric Service Supplies Company, I found what must be the ultimate in High Voltage DANGER signs. Enameled steel signs were supplied in both plain and illuminated forms. The signs were made from a base of No.16 cold rolled annealed English charcoal iron, the enamel being burned into the ores making them practically indestructible. They were easily kept clean and had a bright polished surface that was not affected by the weather.

Standard stock signs were available with white letters on either a dark blue or red background. The sign to the right was adopted by a great many industrial plants and mines. The circle and DANGER letters were in red on a white background. The cost of this 12" x 12" sign was $1.30 each.
	The sign to the left reads "DANGER, 2200 VOLTS ON THESE WIRES."
The sign to the right reads "DANGER, KEEP OUT.' Both are printed in six different languages. The letters were white on a blue background. The cost of this 12" x 12" sign was $1.30 each.

The illuminated signs were designed for use in the mines, tunnels, subways and industrial plants. They consisted of a steel frame formed at the top in a shape of a hood, under which a weatherproof socket for one incandescent lamp was placed. The hood was given a coat of aluminum paint on the inside which acted as a reflector as well as a protection for the lamp. The standard 10" x 12" sign was attached to the frame with machine screws.

This sign reads "DANGER - DO NOT TOUCH THE WIRES" in English, Italian, Lituanian, Polish and Slavok. The price was $2.00 each (without the bulb).

The "Safety First" campaigns increased the demand for these signs. The 6" x 14" DANGER sign was $1.75 each, while the 6" x 30" SAFETY FIRST sign sold for $3.00 each.