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Light Without Light Bulbs

Light Without Light Bulbs
A darkened factory floor was illuminated with bright light, but none of the light fixtures contained light bulbs. How could this happen?
Mysteries of Science


An old factory building was being rehabbed for a new occupant. All of the light bulbs had been removed long ago and the brass sockets had oxidized, and some had significant corrosion.

An industrial cleaning company had been hired and they were asked if they could do something with the light bulb sockets. They suggested that cleaning with steel wool would work well. They insisted that the power for the lights be locked out to make sure workers could not be exposed to an electrical hazard.

Two weeks later, the building had been cleaned and painted, but light bulbs had not yet been installed in a large warehouse section of the building, although the sockets had been meticulously buffed and cleaned.

The new tenant and his electrician were checking the building well into the evening. The electrician turned on his flashlight so that the two could find their way out. But the tenant remembered that power was still locked out and he wanted to have lights working the next day. So he asked the electrician to power the ceiling lines.

The electrician removed the electrical lock-out and threw the main breaker. Suddenly the large room was filled with light even without light bulbs.

But the light was short-lived followed by fireworks of blue sparks, yellow flames and a chorus of snaps and crackles. So what happened?

Here's the rest of the story.

A rehab crewman had meticulously cleaned each socket with steel wool, but he had an unusual routine to avoid skipping any sockets. He simply left a wad of steel wool in each socket after cleaning.

Since he was also going to be the one who screwed in the new light bulbs, he would recover the steel wool while installing each bulb. The unsuspecting electrician had no idea that each socket contained steel.

So when the power was turned on, the steel wool acted like light bulb filaments. The electrified steel wool lit up and put on a show.

Is there anything to be learned here? Probably not! This was a case of two unplanned events intersecting to create an unusual incident.


The electrician should not have been able to remove the lockout. The worker should have had the only key to the lock. That is how tag-out-lock-out is supposed to work.
Richard Grime, Analytical Technology, Inc.
There is definitely something to be learned. The crewman who was performing the cleaning was responsible for locking out the electrical supply until his work was complete. No one, other than that crewman, should have removed the lockout. The electrician is at fault in this case.
Jim Blundon

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