Using 220-240v Bulbs In 110v Lamp?

[wpcoe]

A friend surprised me when he said he bought some 110v lamps in the U.S. and brought them over here to use without a voltage transformer. He simply uses 220-240v bulbs. Is that safe? I was trying to think of some reason why it WOULDN'T work or be safe, but am not sure. Is the switch and/or wires in a 110v lamp identical to those used in 220v lamps?

I have yet to find a nice floor lamp in Thailand that costs less than B5000. I can find lamps I like in America for a lot less, so it's tempting. e.g. A simple vertical torchiere halogen lamp. They range from about US$15 to US$50. The light from a tungsten bulb seems much closer to natural light than a standard or energy-saving bulb, and these lamps usually have a rheostat dimmer switch. Try to find a tungsten-bulb floor lamp in Thailand.

[backflip]

It depends upon the type of bulb. Incandescent bulbs will be OK. Halogen bulbs use DC, provided by a transformer in the lamp. Plugging a 120V transformer with dimmer into a 220V outlet will give you a nice cloud of smoke, followed by a possibility of sparks.

[chownah]

Aside from lamps that contain transformers (like backflip mentioned) it seems to me that most lamps are rated for watts and not volts....if you don't exceed the wattage then I think you'll be ok.

Chownah

[Farma]

I'll confirm backflips warning about Halogen bulbs. I had one catch fire in a 240v wired room I stayed in not so long back. The owners had renewed the furniture and mistakenly bought 110v standing lamps.

These lamps were close to long drapes and within minutes of the lamp being switched on there was a flash bang and the bulb caught fire. Luckily I managed to pull it away from the drapes before they caught alight.

[wpcoe]

Wonderful. My friend's 110v gauche Tiffany lamps are fine, but the lamp *I* want to use, I can't.

I'm glad I asked, as I never would have thought about a transformer (AC > DC) being involved.

Does anybody know of a shop that sells 220/240v halogen floor lamps, either Pattaya or Bangkok? All I seem to be shown when I point to the halogen bulb display is outdoor halogen flood lamps. I suppose I *could* use them, but it'd be mighty bright in the living room.

Thanks for the quick feedback. The resources available on this forum astound me sometimes.

[Farma]

Don't give up on your lamp just yet.

There are small 240-110v transformers you plug into a wall socket. I bought one a while back for less than 200B. They look like one of those travellers multi plugs, slightly bigger than a matchbox and should easily handle a lamp.

I asked at my local hifi shop, he rode off to another shop and returned with it 5 minutes later.

[ovenman]

There are small 240-110v transformers you plug into a wall socket. I bought one a while back for less than 200B. They look like one of those travellers multi plugs, slightly bigger than a matchbox and should easily handle a lamp.

I'd be careful about using one of those cheap voltage transformers with a halogen lamp as those lamps suck up a fair amount of power.

[Farma]

Oops, I see your right ovenman.

From the State University of New York at Buffalo web site

"The UB energy conservation program actively discourages the use of halogen Torchiere-type floor lamps. These lamps draw 200-300 watts of electrical power, many times that of conventional incandescent or overhead fluorescent lighting. Moreover, due the temperature of the halogen bulb, halogen fixtures pose a fire risk."

[Tywais]

Aside from lamps that contain transformers (like backflip mentioned) it seems to me that most lamps are rated for watts and not volts....if you don't exceed the wattage then I think you'll be ok.

Chownah

If it is a filament (incadescent) light bulb it will use four times the wattage at twice the voltage. So if it is a 100W 110V bulb used with 220V it will use 400Watts. It will be bright and it's life time will be shortened considerably.

[autonomous_unit]

The cables may even be over-sized because they were designed to take more current. However, the mechanical switch could be a concern, as with twice the voltage it may spark more in the moment before it is opened/closed.

I don't know whether the switch designs actually vary around the world for this type of product, but as the voltage goes up, so does the spark gap width... I'm not sure I'd want to take my chances on something like that, although I suppose we take our chances every day with some of the cheap local stuff.

[chownah]

Aside from lamps that contain transformers (like backflip mentioned) it seems to me that most lamps are rated for watts and not volts....if you don't exceed the wattage then I think you'll be ok.

Chownah

If it is a filament (incadescent) light bulb it will use four times the wattage at twice the voltage. So if it is a 100W 110V bulb used with 220V it will use 400Watts. It will be bright and it's life time will be shortened considerably.

I didn't mean to use the 110V bulb....a 110V bulb will burn out almost instantly if used with 220V I think. It's the lamp that the bulb screws into that is usually rated for how many watts it can handle...so....if it is a 60 watt lamp then you should be able to run it with a 60 watt bulb 220V.....although autonomous_unit has a good point about the switch. My experience with using a 110 V switch with 220V was that the switch burned out (from the arcing) after many uses while the 220V switch I installed to replace it never burned out. It is entirely possible that a switch on a 110V appliance could be rated for 220V especially in this day and age when appliances manufacturors sell products internationally. You could remove the switch and see if it says its voltage rating.

Another idea: take the lamp you like to an electrical shop and ask them to rewire it completely for 220V including any transformers. It should be an easy job for them and not too expensive...but don't know for sure.

Chownah

[Tywais]

I didn't mean to use the 110V bulb....a 110V bulb will burn out almost instantly if used with 220V I think. It's the lamp that the bulb screws into that is usually rated for how many watts it can handle...so....if it is a 60 watt lamp then you should be able to run it with a 60 watt bulb 220V.....although autonomous_unit has a good point about the switch.

Sorry about that, some reason I was thinking lamp=bulb, late night. A few things regarding the voltage rating: The switch usually is rated by volts and current - too much current at a higher then rated voltage will cause more arcing (short life time). 2nd, the wire will probably be fine for the current (higher current for same wattage rating but lower voltage) but if rated for 110 could have potential to break down at 220 (though not too likely due to the margins put into them, except for cheap stuff). The sockets are usually rated by wattage which equates to heat and could deteriate over time, so that shouldn't be an issue with same wattage 'bulbs'. Guess I'm in agreement, the switch would be the weakest link in the chain.

[Naam]

A friend surprised me when he said he bought some 110v lamps in the U.S. and brought them over here to use without a voltage transformer. He simply uses 220-240v bulbs. Is that safe? I was trying to think of some reason why it WOULDN'T work or be safe, but am not sure. Is the switch and/or wires in a 110v lamp identical to those used in 220v lamps?

don't worry and use 220V bulbs. cable, switch and sockets are designed to handle AMPs not VOLTs. using 220V bulbs means all afore-mentioned parts have to bear less "load" and there is virtually no difference between 110 and 220V as far as sparks are concerned.

[mackayae]

V=IR. You can work it out from there. Be very carefull about mixing US 120v appliances with Thai equipment. In the US the neutral is grounded, therefore, one leg of the 120v is grounded. Consequently, most US appliances are designed with this in mind. You might notice that the plug is not symmetrical. In Thailand the 240v is not neceesarily grounded, also no two houses/buildings are wired the same. When you use a 120v appliance thru a step down/up transformer you will not know what you are getting with respect to the ground. Consequently, I would not do it. However, if you do, make sure the breaker protecting this circuit is a ground-fault breaker; that way your life will be protected.

Halogen lamps burn exceedingly hot. Give them plenty of space, their radiated heat can ignite any nearby combustible material such as wood, cloth, etc.

[thaihome]

V=IR. You can work it out from there. Be very carefull about mixing US 120v appliances with Thai equipment. In the US the neutral is grounded, therefore, one leg of the 120v is grounded. Consequently, most US appliances are designed with this in mind. You might notice that the plug is not symmetrical. In Thailand the 240v is not neceesarily grounded, also no two houses/buildings are wired the same. When you use a 120v appliance thru a step down/up transformer you will not know what you are getting with respect to the ground. Consequently, I would not do it. However, if you do, make sure the breaker protecting this circuit is a ground-fault breaker; that way your life will be protected.

Halogen lamps burn exceedingly hot. Give them plenty of space, their radiated heat can ignite any nearby combustible material such as wood, cloth, etc.

You may be actually making a mistake about the 220v used in Thailand (and almost the rest of the world)that I made up until a few years go when I checked the voltage with a meter. In Thailand, the 220v is between the “hot” wire and the neutral, which in the US is 120 volts. There is not 2 hot wires like the 220 volt in the US. You can see this when you open a panel and see the breakers are all single pole and not double pole like 220 volts in the US.

The Thailand 220v volt plug and US 120 volt plug are the same, and like in the US are often polarized to make sure that the hot and neutral are not switched which can affect some electronic equipment.

Note, as you said, Ohm’s law works in Thailand as well, 10 amp breakers are used just like 20 amp in the US.

TH

[elkangorito]

A friend surprised me when he said he bought some 110v lamps in the U.S. and brought them over here to use without a voltage transformer. He simply uses 220-240v bulbs. Is that safe? I was trying to think of some reason why it WOULDN'T work or be safe, but am not sure. Is the switch and/or wires in a 110v lamp identical to those used in 220v lamps?

I have yet to find a nice floor lamp in Thailand that costs less than B5000. I can find lamps I like in America for a lot less, so it's tempting. e.g. A simple vertical torchiere halogen lamp. They range from about US$15 to US$50. The light from a tungsten bulb seems much closer to natural light than a standard or energy-saving bulb, and these lamps usually have a rheostat dimmer switch. Try to find a tungsten-bulb floor lamp in Thailand.

I take that when you say "lamp", you actually mean "light" (or light fitting). "Lamps" are bulbs, tubes or globes.

It depends upon the type of bulb. Incandescent bulbs will be OK. Halogen bulbs use DC, provided by a transformer in the lamp. Plugging a 120V transformer with dimmer into a 220V outlet will give you a nice cloud of smoke, followed by a possibility of sparks.

Sorry Backflip but Halogen lamps do not use DC. The transformers used are cheap & nasty step down transformers. The use of DC with Halogen lamps will decrease the life of the lamp.

Halogen "Eye" lamps, which are available in 25 or 50 Watts with a choice of beam widths of between 25 & 55 degrees, are 12 volt AC lamps. This means that if used on a 220 to 240 volt supply, the step down ratio of the transformer is 20:1. Since P=EI, I therefore equals P divided by E.

For 240 volts; 50W divided by 240v = 210mA approx. (current coming out of your power point)

For 12 volts; 50W divided by 12v = 4.2 Amps. (current going through the lamp filament)

Or 0.21 multiplied by 20 = 4.2 (using the 20:1 ratio)

So, the 240 volt side of the transformer will use 210mA (discounting transformer losses) whilst the 12 volt side will use 4.2 Amps.

Oops, I see your right ovenman.

From the State University of New York at Buffalo web site

"The UB energy conservation program actively discourages the use of halogen Torchiere-type floor lamps. These lamps draw 200-300 watts of electrical power, many times that of conventional incandescent or overhead fluorescent lighting. Moreover, due the temperature of the halogen bulb, halogen fixtures pose a fire risk."

This statement is misleading. It is impossible for a 50 Watt lamp to draw 200 - 300 Watts. The only added power consumption related to low voltage Halogen lamps is the inefficiency of the supply transformer. These transformers are normally rated at 100 VA (Watts) in order to supply one 50W Halogen lamp. They are usually made in China & are very inefficient, which is evident in the amount of heat they generate. As a general rule, these transformers waste about 40 to 50 Watts of power as heat. In effect, each 50 Watt Halogen lamp + transformer will absorb about 100 Watts of electrical power.

If you decide to use a 110 volt light fitting (not "lamp") on a 220-240 volt supply, the only thing to be aware of is the insulation rating of any cables & the voltage/current rating of the switchgear. Most cables are rated at a minimum of 300 volts AC (600-1000 volts in Australia). Switchgear (switches) will have an AC rating & may have a DC rating also. If you use a 110 volt switch on a supply of higher voltage, its life will be shortened due to a slight increase in arcing. Do not exceed the current rating of the switch. Do not use AC rated switches on DC.

In the next couple of days, I will be posting a document in the "Domestic Electrical Wiring" topic, which will cover most generally used lighting.

[wpcoe]

I take that when you say "lamp", you actually mean "light" (or light fitting). "Lamps" are bulbs, tubes or globes.

You take correctly.

Where I grew up we called the appliance which stands on the floor with a power cord, a light bulb and (usually) a lamp shade a "floor lamp." Now I know we were wrong: it's a floor light!

Seriously, please do continue your explanations. I'm learning lots in this discussion.

[wpcoe]

BTW, the halogen "floor lamps/lights" I'm talking about do not use the "eyeball light" type of bulbs, they use the cylindrical "bulbs" about 10cm long.

I now have a question, though, about the halogen "eyeball lights" like you install in ceilings. There is a multitude of light fixtures which use a transformer, but there are also (fewer selections of) light fixtures which do NOT use a transformer and use a 220/240v bulb. Since the transformers used in the former are so inefficient, what about using only eyeball light fixtures that do not use the transformer? I am re-doing my ceilings to have a drop down ceiling around the edges and want to install such lights so this is quite relevant to me right now. Which type of light fixture is better: with transformer, or without?

[dvk1951]

Thanks Elkangorito,

You saved me the trouble of posting the same info. Obviously you are a man with an education in 'lektrisity'.

This statement is misleading. It is impossible for a 50 Watt lamp to draw 200 - 300 Watts. The only added power consumption related to low voltage Halogen lamps is the inefficiency of the supply transformer. These transformers are normally rated at 100 VA (Watts) in order to supply one 50W Halogen lamp. They are usually made in China & are very inefficient, which is evident in the amount of heat they generate. As a general rule, these transformers waste about 40 to 50 Watts of power as heat. In effect, each 50 Watt Halogen lamp + transformer will absorb about 100 Watts of electrical power.

If you decide to use a 110 volt light fitting (not "lamp") on a 220-240 volt supply, the only thing to be aware of is the insulation rating of any cables & the voltage/current rating of the switchgear. Most cables are rated at a minimum of 300 volts AC (600-1000 volts in Australia). Switchgear (switches) will have an AC rating & may have a DC rating also. If you use a 110 volt switch on a supply of higher voltage, its life will be shortened due to a slight increase in arcing. Do not exceed the current rating of the switch. Do not use AC rated switches on DC.

In the next couple of days, I will be posting a document in the "Domestic Electrical Wiring" topic, which will cover most generally used lighting.

[chownah]

Where I grew up a lamp was a complete unit with a plug and a bulb (also called a light bulb). We had floor lamps, table lamps, and even lava lamps. We did not have floor lights, table lights, or lava lights. A lamp had to be portable (meaning it plugged into an outlet) and if a light was built into a structure then it was called a light or a light fixture....

Chownah

[Tywais]

Where I grew up a lamp was a complete unit with a plug and a bulb (also called a light bulb). We had floor lamps, table lamps, and even lava lamps.

Appears both meanings are correct:

Definition:

(n) lamp (an artificial source of visible illumination)

(n) lamp (a piece of furniture holding one or more electric light bulbs)

[elkangorito]

BTW, the halogen "floor lamps/lights" I'm talking about do not use the "eyeball light" type of bulbs, they use the cylindrical "bulbs" about 10cm long.

I now have a question, though, about the halogen "eyeball lights" like you install in ceilings. There is a multitude of light fixtures which use a transformer, but there are also (fewer selections of) light fixtures which do NOT use a transformer and use a 220/240v bulb. Since the transformers used in the former are so inefficient, what about using only eyeball light fixtures that do not use the transformer? I am re-doing my ceilings to have a drop down ceiling around the edges and want to install such lights so this is quite relevant to me right now. Which type of light fixture is better: with transformer, or without?

The type of lamp you're talking about is physically quite small, which is why it is primarily used at low voltages (generated heat makes it very fragile when on). As you mentioned, the Halogen Eye lamps are available in 220-240 volts but they are more susceptible to a reduction in life as a result of poor quality electrical supply. The transformer effectively dampens many electrical supply faults.

I have just posted a paper on domestic lighting in the topic of Domestic Electrical Wiring, which may be of some use to you but I'll post it here anyway.

[wpcoe]

I have just posted a paper on domestic lighting in the topic of Domestic Electrical Wiring, which may be of some use to you but I'll post it here anyway.

Just a comment on the "myth" section:

Myths.

Low voltage halogen lighting is not cheaper to operate.

Fluorescent lamps do not emit dangerous UV radiation.

Constantly switching lights on & off does not save money.

Dimming lights does not save money unless a solid state dimmer is used.

It's not clear whether what you post below the heading is the true or the myth statement. I'm assuming they are the true statements, not the false mythical statements. i.e. The myth is "Constantly switching lights one & off does save money," and the truth is "Constantly switching lights one & off does not save money."

[elkangorito]

I have just posted a paper on domestic lighting in the topic of Domestic Electrical Wiring, which may be of some use to you but I'll post it here anyway.

Just a comment on the "myth" section:

Myths.

Low voltage halogen lighting is not cheaper to operate.

Fluorescent lamps do not emit dangerous UV radiation.

Constantly switching lights on & off does not save money.

Dimming lights does not save money unless a solid state dimmer is used.

It's not clear whether what you post below the heading is the true or the myth statement. I'm assuming they are the true statements, not the false mythical statements. i.e. The myth is "Constantly switching lights one & off does save money," and the truth is "Constantly switching lights one & off does not save money."

Sorry Wpcoe, you are correct. I should have labelled the section "Truths" or reversed the meaning of the statements. Thanks for pointing it out to me.

[astral]

The use of DC with Halogen lamps will decrease the life of the lamp.

So how do they manage with Halogen lamps in car headlights?

That is definitely DC.

[elkangorito]

The use of DC with Halogen lamps will decrease the life of the lamp.

So how do they manage with Halogen lamps in car headlights?

That is definitely DC.

A bloody good come-back Astral but it is easy to answer.

The halogen lights/lamps used in motor vehicles are quite different to those used in the home. The filaments are much thicker (usually a dual layer winding up to 3mm thick) than those found in the "home" version, which is why they are very reliable (& expensive). Also, the quartz envelope is physically bigger than that found in the "home" version, which allows for better heat dissipation. The price of an automotive lamp reflects its reliability.

Generally, using DC to supply ordinary incandescent lamps will lengthen the life of the lamps (marginally) but the light output decreases rather rapidly. There are grounds for believing that DC may assist in the removal of filament material by electro-deposition, as well as evaporation. These actions will ultimately blacken the inside of the glass envelope.

Also attached, Rev 1 of the domestic lighting paper.

[reasonstobecheerful]

Some of you seem to be professionals.

A friend of mine owns a company that produces own-design high quality low voltage lighting regulation. They feature softstart and tight voltage regulation at the bulb even for very long runs. This increases the life of the bulbs enormously.

You may like to check it out

http://www.multiload.co.uk/

[wpcoe]

I've not yet contracted the work, so haven't consulted with the electrician nor ceiling installers, but are there any do's and don'ts with mounting the transformers and actual halogen fixtures recessed into the ceiling that I should be alert to?

I'm planning to add a 30cm x 30cm drop ceiling (I think that's the term?) around the perimeter of each room. The walls are the standard brick construction and the existing ceiling is gypsum/dry wall. I'm concerned about the heat generated by the transformers and the bulbs. Should the transformer be mounted on the concrete wall, or is it ok to mount on the gypsum dry wall, or does it matter? Is the 30cm x 30cm area ok if they leave the existing ceiling above it, or should they bust out the existing ceiling to allow more ventilation for heat dissipation? I'm not always this paranoid, but would like to take advantage of the free, professional-level advice that's obviously available on this forum. :-)

[elkangorito]

Some of you seem to be professionals.

A friend of mine owns a company that produces own-design high quality low voltage lighting regulation. They feature softstart and tight voltage regulation at the bulb even for very long runs. This increases the life of the bulbs enormously.

You may like to check it out

http://www.multiload.co.uk/

Your friends site looks very interesting. I think that the "Lamp Conserver" would be a good seller in Thailand.

[elkangorito]

My comments in blue.

I've not yet contracted the work, so haven't consulted with the electrician nor ceiling installers, but are there any do's and don'ts with mounting the transformers and actual halogen fixtures recessed into the ceiling that I should be alert to?

I'm planning to add a 30cm x 30cm drop ceiling (I think that's the term?) around the perimeter of each room. The walls are the standard brick construction and the existing ceiling is gypsum/dry wall. I'm concerned about the heat generated by the transformers and the bulbs. They generate enormous heat. Should the transformer be mounted on the concrete wall, or is it ok to mount on the gypsum dry wall, or does it matter? I certainly wouldn't mount it on the Gyprock because I have known of cases where the paper covering has caught fire. Is the 30cm x 30cm area ok if they leave the existing ceiling above it, or should they bust out the existing ceiling to allow more ventilation for heat dissipation? The more ventilation, the better with these types of light fittings. If it was my house, I'd 'bust out' a portion of the old ceiling. I'm not always this paranoid, but would like to take advantage of the free, professional-level advice that's obviously available on this forum. :-)

I'd also use electronic transformers because they generate less heat & are much more efficient than the standard supplied transformers. Don't forget to avoid any covering in the ceiling space around the light i.e. fibreglass insulation.