A really stupid question about 110v transformers

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Forum topic by 404 - Not Found posted 06-11-2012 07:46 PM 3858 views 0 times favorited 4 replies Add to Favorites Watch
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404 - Not Found

2544 posts in 3207 days

06-11-2012 07:46 PM

This bit is for the benefit of LJ’s across the Atlantic – in England and Ireland we’re on 230/240V mains. If you are working on a building site, power is stepped down to 110v for Health & Safety reasons using a transformer.

Now to the dumb question, why is there a reset button on a 110v transformer and what is it for?
Is the reset button supposed to be pressed when you’re plugging it in?

I asked the guy in the hardware store and he didn’t know.
I’m not losing sleep over this vexing issue, but if anyone can enlighten me I would be grateful.

4 replies so far

View knotscott's profile


8178 posts in 3613 days

#1 posted 06-11-2012 07:53 PM

I’m no electrician, so I can only guess, but stepping down the voltage to 110v should also double the amperage draw, so it’s very feasible that quite a bit of amperage could flow through the transformer….thus a circuit breaker with a reset button for protection from overload.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View Mosquito's profile


9566 posts in 2530 days

#2 posted 06-11-2012 07:54 PM

That was my guess too Scott

-- Mos - Twin Cities, MN - -

View MrUnix's profile


7106 posts in 2436 days

#3 posted 06-11-2012 07:54 PM

And you use 50hz instead of 60hz :) As for the reset button, only thing I can imagine is that the thing has an internal circuit breaker for protection, and that button is to reset it when it gets tripped.


-- Brad in FL - In Dog I trust... everything else is questionable

View Scot's profile


344 posts in 3634 days

#4 posted 06-11-2012 08:59 PM

Knotscott is correct. A CB is installed because of the change in amperage.
When voltage goes up amperage goes down, when voltage goes down amperage goes up.
Even though you may have a CB feeding a transformer (primary side), the secondary side needs to have its own over current protection.

-- If the old masters had power tools, they would have used them. So get off your damn High Horse.

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