Comments on: running a 240V device on 110V

Question: running a 240V device on 110V

randomstriker — Sun, 30 Oct 2005 12:59:27 -0800

Will a 240 VAC panini grill work on 110 VAC? I found an old panini grill in my grandma's appliance collection. It is one of those really great, robust grills built in the 70s. It weighs a tonne. Thing is, she had brought it over from Europe many, many years ago, and it is supposed to run on 240 VAC. Can I just slap on a new plug and run it on 110 VAC? I doubt there are any solid state electronics in this device. I'd rather not buy a voltage converter -- I could probably buy a new grill for the same price.

By: andrew cooke

andrew cooke — Sun, 30 Oct 2005 13:06:44 -0800

well, it won't explode.
won't get very hot either, though. it's going to be simple resistive heating which means that it's only going to put out one quarter the heat. even if it's thermostat controlled (so it's more powerful than "need be", then cuts out when it gets to the right temperature) i bet it never reaches the right temperature.
give it a go. odds are it won't work, but odds are it won't do any damage either.

By: PurplePorpoise

PurplePorpoise — Sun, 30 Oct 2005 13:13:56 -0800

Thre might also be a voltage frequency difference in addition to total voltage.

I'd either get a transformer or buy a new grill - I wouldn't risk damaging the circuit breaker for the house or risk a short & subsequent fire hazard.

By: andrew cooke

andrew cooke — Sun, 30 Oct 2005 13:17:14 -0800

frequency is unlikely to make any difference. i work in a place with 50Hz 110V (stepped down from chilean 220V 50Hz) and american components for anything except electric clocks work just fine.

nor is it likely to cause a short. the resistance is higher than you'd need for correct functioning, since it has to work with a higher voltage.

By: whoda

whoda — Sun, 30 Oct 2005 13:19:24 -0800

Run it off the outlet for your clothes dryer. 220V versus 240V will be close enough to let you grill away.
You'll have to get the keyed plug from a hardware store and wire it up yourself, but it will work.

By: andrew cooke

andrew cooke — Sun, 30 Oct 2005 13:23:33 -0800

you have a different voltage just for clothes driers?!

By: Mars Saxman

Mars Saxman — Sun, 30 Oct 2005 13:40:34 -0800

yes, it's common for an American house to have one 240V circuit in the garage or laundry room, specifically for the clothes drier.

By: odinsdream

odinsdream — Sun, 30 Oct 2005 13:42:06 -0800

Sure do.

By: mendel

mendel — Sun, 30 Oct 2005 14:07:19 -0800

Clothes dryers and electric ovens. Running off of the stove's 220V plug might be more convenient for a cooking-thing, if any value of "pull the appliance out from the wall and unplug it" could be considered convenient.

I'd just buy a new grill.

By: zsazsa

zsazsa — Sun, 30 Oct 2005 15:03:13 -0800

andrew, North American dwellings usually have split phase power. High-power appliances like electric clothes dryers and ovens are connected across the two live wires for an effective 240V. So the 240V is essentially "free," making it a (little bit) less dumb than it seems.

By: andrew cooke

andrew cooke — Sun, 30 Oct 2005 15:36:13 -0800

thanks, that's interesting.
i was wondering how that would connect to a tripplepahse distribution network (which i was assuming you have in the usa), and ended up reading this article (scroll down to "single phase loads"), which seems to suggest that it's likely 208V. or am i confusing things?
disclaimer - it's a long time since i tried to understand multiple phase systems...

By: Chuckles

Chuckles — Mon, 31 Oct 2005 01:15:32 -0800

Here is a related question: How to plug in an RV trailer.

In that question eriko gives a nice diagram of how power is distributed residentially in North America. Also, I link to a site that discusses all the standard receptacles you might see in North America, although 99% of them are very rare. (I would add, these guys have actual pictures of most of the NEMA receptacles, but without proper nomenclature).

My understanding is that in large buildings you see 120V 3 phase distribution, where 120V comes from a particular phase to neutral and 208V from one phase to another. The 208V being needed as an alternative to the household 240V. I have no experience with such things.

By: Chuckles

Chuckles — Mon, 31 Oct 2005 02:03:08 -0800

Regarding the frequency difference:

Line-frequency transformers are slightly less efficient at 50Hz than 60Hz. Also, in a 50Hz system the smoothing capacitor after a rectifier must be slightly larger for the same load regulation.

This can reduce the RMS power output at acceptable distortion levels in an audio amplifier by quite a bit (about 10% lower maybe... since hearing is logarithmic, it isn't really a big effect...). It would have a reduced effect on a switching power supply because there is no line-frequency transformer. The difference in frequency would have no effect at all on a heating element like a grill.

By: Chuckles

Chuckles — Mon, 31 Oct 2005 02:35:53 -0800

Regarding safety:

whoda, it would be very bad to run it from the dryer or oven outlet because they are fused for too much current. However, in Canada randomstriker should have a kitchen split outlet, which would be better. You could wire another outlet off that circuit, but remember to choose the correct rated receptacle and wire for the voltage/current rating of the receptacle you are making. Still pretty non-standard...

Here is a very interesting product that gives you 240 volts without a transformer by plugging into two independent outlets (like the top and bottom outlet in a kitchen split). A common thought, but I've never seen a product that does it, and with safety approvals too!

PurpolePorpoise, sorry to be nasty, but please reserve the FUD for cases where a safety issue actually exists. Not that it is particularly appreciated in such cases either, actual reasons why there might be a risk would be better.

By: eriko

eriko — Mon, 31 Oct 2005 05:52:40 -0800

As mentioned, there is a 15A/240V approved US outlet, the NEMA 6-15R. Take a normal US outlet (the NEMA 5-15R), and rotate the blades 90 degrees, like so.

You can have an electrican wire up this outlet, and while he's there, install the correct 6-15P plug to match, and then it'll work great. A small number of houses with unusally large electric ovens or stoves will already have a 6-15R outlet in the kitchen.

Chuckles' box is just a variation on that, but it demands that you can get to both phases in one room. If you have a kitchen split outlet, you're golden, but if you don't know how to tell, you'll need an electician to come find it and install it. If you are going to do that, the only reason to install the split outlet is that you can use each outlet as a normal 120V outlet, or combine them with the box above to make a 240V outlet.

Personall, I'd just install the outlet.

As to using it on 120V? It'll draw whatever current it draws, probably 4-8 amps. But with only 120V driving it, i'll only use half the power, thus, it'll only make half as much heat. It may work, but take longer to cook, or it may just get warm.

By: eriko

eriko — Mon, 31 Oct 2005 05:55:39 -0800

Andrew Cooke: Yes, we have different outlets. American outlets were developed for lights, and we started dealing with larger loads later. The bad thing is that for very large loads, we need a different outlet. The good thing is that for the vast majority of loads, all well under 1000W, we can use a much smaller plug/jack combination. (Of course, since we really need much less than 120V, and DC, we end up wasting that space advantage on wall warts.)

The UK plug/outlet system is one of the safest and most capable in the world, but at the cost of being very large, and quite expensive to install.