Mostly careful with 120V → 240V conversion

I ran new wires through my walls, installed 20A twistlock (L620) 240V power. I was careful to go through the box and move the power supply switches from 115V to 230V before I switched the plug at the end of the wire, to avoid exploding power supply accidents. Turned on the breaker, turned on the switch, thought “huh, that fan runs faster than I remember,” and smelled a bit of magic smoke.

Yeah, there was one more component I wasn’t thinking about.

I ordered an EC fan as a replacement. It can take anything from 90V to 270V AC (or, I think, DC).


When the fan is what dies, the magic smoke doesn’t even dissipate!


That’s where a multimeter comes in handy. All our circuits in the UK are 240volt so the dual voltage isn’t a problem. Because we have this higher voltage, our circuit protection is of a really high standard with not only overload breakers but also earth leakage breakers. All our power outlets are 3 pin Live Neutral and earth with, in the case of sockets, specialised plugs that are always 3 pin and are fused from 1amp up to 13amp Makes life much simpler.
We use 240v on our lighting as well. That might give the USA users the collywobbles perhaps but death from careless use of 110v is similar to death from 240v but the latter is just a bit quicker.
Our 3 phase system is 440 volts across the phases but that will only appear in non domestic environments. That is a quick kill voltage as a friend of mine found to his cost.

Oh, it wasn’t a multimeter problem. It was an out-of-sight-out-of-mind problem. I carefully checked everything in the control box. It was just that the fan is outside the box.

Among other things, I’m an electronics hobbyist. I don’t actually know for sure how many multimeters I have. I’ve done more complex work than this, including a complete conversion of my lawn tractor to electric power. I’m sufficiently aware of code that I tend to find out-of-code problems with work by qualified electricians on my house that the inspectors missed. I even have opinions about things that were allowed in code last time I checked that I think shouldn’t normally be (like shared neutral returns, which can present a fire hazard with unbalanced loads and any fault in the shared neutral).

I just failed to think outside the box this time.