I've tried to find this via the search function, as I'm confident it's been discussed before, but to no avail. I recall folks mentioning that running 220v machines on 110v outlets without using a step up transformer, just native current, can run the risk of overloading the stock wiring on the machine. Is this correct?

Just do the math...approx. double the current will flow through the wires and switches not necessarily designed to carry that much.
If the machine is of low power it might work but I would not dare use it for longer than some testing under close watch.

Yes, the switches are the Achilles heel if ampere rating is too low for 110V. I fried a 9 amp switch in a Faemina with a 110V element installed. Analog machines may do OK, but anything with electronic controls would not work.

Well, I'm looking at vintage levers that I keep on for maybe 30 minutes at a time. Sounds like even that might be pushing it? I've run a Caravel with original (for 220v) wiring with a 110v element for close to four years now with no issues, but I rarely have it going for longer than 20 minutes. Right now I have been running an early 60s 220v Europiccola on 110v, also typically no longer than 20-30 min.

Most of the damage seems to occur while switching. What alerted me to the problem with the Faemina was a green flash from the contacts arcing. The contacts were actually fine, the plastic housing basically burned and disintegrated. There's a thread documenting my solution, never did find a direct replacement rated above 9 amps.

I try not to switch the hi/low while powered on, and so far it seems fine. Still looking for a 110V switch that will fit the opening in the base. This is all specific to the Faemina. Machines using other types of switches may have a direct 110V counterpart that would fit.

If you run a lever with a 220 v element on 110 v mains without changing the element, your current draw will be cut in half as will the power and it will take longer to heat the water.

But if you take a 220 v machine and put in a 110 v element rated for the same power you will draw twice the current and may exceed the current ratings of the wiring and switches that were designed for the 220 v machine.

Ohm's Law: I (current) = E (voltage) / R (resistance). Only the voltage is changed (halved) in your scenario, assuming the original 220 v elements were not changed.

Why not get a 220 line or transformer? Much safer, or at least rewire using some decent wire replacing the old wire with it's old insulator...

yakster wrote:If you run a lever with a 220 v element on 110 v mains without changing the element, your current draw will be cut in half as will the power and it will take longer to heat the water.

Is even worse than that. At half the current and half the voltage, you only get 1/4th the power. So your 800 watt element is only generating 200 watts of heat. Might eventually come up to pressure but would take over 4 times as long even if the system is very well insulated.

Doing the reverse, running 110V components at 220V is unsafe. Twice the current (amperage) and 4 times the power (wattage) will probably damage the component or set something on fire.

IF resistance is constant and you reduce the voltage by 1/2 then the current is reduced by 1/2, E=I/R. When resistance is constant(R) then the voltage(E) varies directly with the current(I).

yakster wrote:Ohm's Law: I (current) = E (voltage) / R (resistance).

correct.

OldNuc wrote: When resistance is constant(R) then the voltage(E) varies directly with the current(I).

correct.

But the thing to understand is that Power (watts) = Voltage (volts) X Current (amps). So when you double your voltage with the same resistance, you get double the current and double the voltage, so you get 4 times the power.