WE 320 Type Explosion Proof (Mine) Phone With F1 Handset

The Western Electric 320, produced primarily in the 1940s and 50s, was designed as an "Explosion-Proof" (or Blast-Proof) telephone. While it is most famously associated with coal mines, it was used extensively across several high-risk industrial environments. Because the internal electrical components of a standard 1940s/50s telephone could create a tiny spark when dialing or hanging up, they were essentially "bombs" in rooms filled with combustible gases. The 320 was designed to solve that. Mines were the most common home for the 320 because of methane gas and coal dust. But the WE 320 was the standard "safety phone" for any facility with a "Class I, Division 1" hazardous rating, like oil refineries and chemical plants, munitions factories, and paint and lacquer plants. The phone features a massive, heavy-duty cast-iron or aluminum housing, designed to contain an internal explosion. If a spark ignited gas inside the phone, the casing was strong enough to keep the flame from escaping and igniting the entire mine.