Mercury light switches

av-geek

I had never heard of mercury switches being used in ordinary light switches until I just recently moved into my new home, but the home inspector said that almost every light switch in the house has a mercury light switch. He said that's what accounts for the smooth operation. IE the switches don't "click" He said that the switches do not wear out like an ordinary light switch, so there's no reason really to replace them unless changes to the electrical system is made. He said to save them not only because they cannot be thrown in the trash, but also because they are not made anymore, and re-purposing them in another location is advisable.

Anybody else familiar with these style light switches? I'd love to find some more, they sound like they are much better than the mechanical switches currently used.

J. V.

I have never seen a mercury switch in a house except in a manual thermostat. How's about a picture. They make non clicking light switches and they are not mercury switches. Coming from a home inspector I can believe it though. He must be an idiot. Mercury is very dangerous.

Ps.............Mercury switches are mechanical in nature.

av-geek

From the outside, they look just like ordinary light switches. I guess when the switch is turned on, it just tips a little vial inside with mercury in it, sort of like an old Honeywell thermostat. He stated the mercury in the switches were not dangerous as long as they were not broken, but to use care if I removed them and not to just throw them in the trash if I replaced one.

I will remove the switch plate on one this evening and take a picture of the switch inside the electrical box.

md2lgyk

You must not be very old. Mercury light switches were common in houses up until around 1970 (when they were probably outlawed). My parents' house, built in 1960, had them. They cost more, but were virtually silent to operate.

Oso954

Although their use dropped off in the 70's, they were still made until 1991. I would attribute the reduction in use to other silent switches being made at a lower cost.
Mercury switches were also used in many of the older appliances and in cars.
Ford and GM did not discontinue the use of mercury switches (primarily as hood and trunk light switches) until the 2002 model year.

sdsester

The problem with mercury is it is cumulative and when you think of all the thermometers, auto components, florescent bulbs, switches, instruments, etc. discarded it adds up. While each individual component may not have much it still contributes greatly to a vast and growing landfill problem.

It is like those little bottles of white out used in offices extensively before computers. Nasty, nasty stuff and as toxic as anything you could imagine. And of course nobody was ever able to use but 1/4 or maybe half a bottle. While a single bottle probably posed no great danger think of how many millions got landfilled?

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operagost

Wite-Out wasn't toxic; however, when it dried it released chemicals that could deplete the ozone layer.

ddawg16

The inspector is correct. As long as the switches are not messed with....leave them in there. For the most part, they never wear out.....

In industry, there is a slow movement to replace all mecury switches.....no one wants the liability if one gets broken....

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Julius793

Interestingly the switch will only work in the upright position and not sideways.

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dmxtothemax

.

I wonder if the mercury glows ?
with the current running thru it ?
Sort of like an mercury arc rectifier !

If you have ever seen one of these in use !
It is something you never forget !

ionized

Mercury switches are very dangerous, indeed. Replace all of them and send them to me!

I'd love to see a large mercury arc valve in operation. I bet it is even better than Nixie tubes.

dmxtothemax

I have indeed seen several in operation.
As a young lad (seventies) my uncle took me to
a city council power station that provided 25 000 vdc for trams,
really unforgetable stuff !
I hate to think what the ultra violet levels were !!