# Can I power a 110VAC heater with 230VAC [closed]

Can I give power supply of 230VAC to 110VAC heater? What is the effects on giving higher voltage on heaters?

Not without providing some method of reducing power.

The standard technique is to use a triac phase control circuit similar to an incandescent light dimmer, with the phase conduction angle set somewhere between 25% - 33%. This will give you approximately the same power as if the heater was running from 115 Vac.

If you attempt to connect the heater directly to the 230V power source, it will consume approximately 4 times the power that it should. That normally leads to smoke and flames.

The change in power is proportional to the square of the change in voltage. 230 / 110 ^2 is about 4.3 times the spec rating.

It was pointed out that my initial statement of 50% conduction angle was too high. The correct value is somewhere between 25% - 33%. I'll calculate the proper value and modify my answer when I get a chance.

• You are right. Chalk it up to a long day. Aug 13, 2015 at 12:28
• It's 36.76%, by my reckoning. I don't have a closed-form expression. Aug 13, 2015 at 12:49

Generally, no.

There are a few examples where you can - "travel hairdryers" are one - where the heater contains two independent heater elements. In this case, the elements can either be wired in series, or in parallel.

In the case of the travel hairdryer there may be a "low/high" power switch that (in 110V-land) sets the elements in series for low power operation, or in parallel for full power.

In 220V-land, only the series connection is available, (enforced by an interlock with the 220V switch or connector) and produces full power.

So if you have a 110V heater with two elements in parallel, you can potentially re-wire them in series for 220V operation, but I would only recommend trying if you are certain that the wiring, insulation, switches, etc are designed for the higher voltage. (Switches are likely to be marked with a voltage rating, wiring often is).

And of course, if you're not certain, don't.

In theory you can use the triac-based solution as given by a previous answer; however, one thing to be aware of is that, whilst this does limit the power input to the heater, it doesn't limit the peak voltage, which will still be 325 V (230 x sqrt(2)). This may be higher than the insulation in the heater is rated for.

The "proper" solution is to use a transformer to reduce the voltage down to 110 V. However, since heaters are typically high-wattage, you will need a pretty beefy (and therefore expensive) transformer to do this. It is often cheaper just to buy a 230 V rated heater instead.

Sure you can then, after a few seconds, expect it to burn out and die. Of course it might survive a few minutes or a few hours but that all depends on the heater. If the 230V AC were a very high frequency such as 10 MHz you might be lucky and find that the inductance of the heater coil lowers current sufficiently to prevent damage but I doubt that your AC supply is 10 MHz.