110 or 220V's

[wapiti22]

Looking to buy a melting pot. Lot's of model come in either 110V or 220V. I have 220V readily available in my garage. What the benefit of one over the other?

[Plate plinker]

Nothing really. Although I do like my heavy loads on 220v so as not to overburden a circuit. Usually (almost always its a dedicated circuit on my 220 stuff.

[sharps4590]

In a heating element as small as a lead furnace, nothing. Provided they're the same wattage, if it's 1500 watts at 120 volts it will still be 1500 watts at 240 volt. The amp draw per leg will be reduced by half at 240 volts. At 240v it will simply be drawing it on two legs rather than one at 120v. 1500 watts at 240v will draw 6.25 amps and at 120v will be 12.5

[alamogunr]

I've got a 220V Pro Melt but only because it was on clearance for a very good discount and I have a 220V circuit for my table saw. Since I cast on top of the table saw(I put a cover on the table) I will never be needing both at the same time.

The 220V furnace came with a European plug which had to be replaced but considering the discount, was no big deal.

[Mal Paso]

For 1500 watts or less 120V is enough and plugs in more places.

[deltaenterprizes]

For 1500 watts or less 120V is enough and plugs in more places.

I agree!

[RAK2018]

I have a lee 120v 20lb pot and a hot plate. Would that be to much for 120 volts.

[Grmps]

I have a lee 120v 20lb pot and a hot plate. Would that be too much for 120 volts.

That depends on the size (AMP's) of the breaker and what else you have on that circuit. Check the amperage rating (draw) of the 2 items and check the breaker for the outlet, also see what else is drawing powder off that same breaker.

[iomskp]

My definition of using single phase against multiple phase, is that it is easier for two or three people to push a car up a hill than one large man to do the same thing.

[lightman]

I can’t really think of an advantage in having a load that small on 240 volts. If you have 240 volts available in your casting area and find a bargain on a 240 volt pot, then go far it. Using 120 volts is much more versatile and an 800-850 watt heating element is really not a great big load. I recently started having a couple of buddies come over to cast. We set up in my shop and cast on my steel work table. At first, we had 3 lead pots and a hot plate plugged into the same 20 amp circuit along with an 8ft light and a radio And had no problems. That did load that circuit pretty good and I’ve since split that circuit up.

[Mal Paso]

Three phase only has mechanical advantage in motors, none in heating elements, almost no one has it in their homes, you would need a 500 pound pot to justify it.

This discussion is all single phase 120/240 volt. A 20 amp 120v circuit max is 2400 watts, the recommended safe load is 80% or 1920 watts. 1440 watts for 15 amps. My old pot was 700 watts and the hot plate 1500 so I ran an extension cord from another circuit for the hot plate. I would not bother with 240 volt unless a single piece of equipment was over 1800 watts. 240V is not cheaper and plugging in is more complicated.

Heat loads are the sort of thing that burn through the quick connections on the back of wall plugs. Side wired to the screws is best. If you don't know the quality of your house wiring, take it easy.

[dragon813gt]

My definition of using single phase against multiple phase, is that it is easier for two or three people to push a car up a hill than one large man to do the same thing.

I doubt anyone has three phase in their home. If they have a large shop they might. But that's the only way. 120/240 are both single phase. Ohms law comes into play w/ this discussion. Watts are still watts and amps are still amps. If you have a 240 outlet available then get a 240 pot. Otherwise just get a 120 pot. Larger equipment and loads is when you want three phase for a myriad of reasons.

[Mike W1]

I believe what we call 120/240 in our household wiring is called 240 center tapped. It's still single phase. I had extra breaker space in my little shop so the 2 pots and the hot plate each have their own breakers. Overkill but nice.

[wapiti22]

Thanks for all the replies! Looks like a 120V unit will suffice.

Now I remember why I became a Mechanical Engineer and not an Electrical Engineer.

[woodbutcher]

[smilie=s: What would be really nice is a setup like on computers.They have a little slide switch on the power supply.Slide it one direction and you have 110V selected.Slide the other way and you have 220 selected.Super simple.Plus 220 uses less amps which means less power consumed and less electric expense.
Good luck.have fun.Be safe.
Leo

[dragon813gt]

Plus 220 uses less amps which means less power consumed and less electric expense.

No it doesn't. Watts are watts. 10 amps at 110 volts is 1100 watts. 5 amps at 220 volts is 1100 watts. There are lots of reasons for using 220 over 110. Reduced power consumption is not one of them.

[woodbutcher]

[smilie=s: Hi Dragon.Thanks for clearing that up for me.Was always told what I posted.
Good luck.Have fun.Be safe.
Leo

[alamogunr]

I should also mention that I've also got a 110V Lee pot. When I got my PID, I asked about the two voltages. The maker(JConn, web site since disappeared) said that the devices, in his anyway, worked on both 110V and 220V. I have since proved it several times. I don't know if that is the norm. I did have to make up two different pigtails to avoid using the wrong one with the higher voltage.

[DocSavage]

I put in a dedicated 20 amp 110 volt line for my Pro Melt and my table saw so I don't worry about popping a circuit breaker elsewhere in the house.

[razorfish]

Imagine you have a nice thick milkshake. It's so thick that it's difficult to slurp up with a regular straw so you get a straw with hole exactly twice the size of the regular straw (a fatter straw). You enjoy your milkshake and drink it all.

The single straw is equivalent to a 110v circuit
The large (fat) straw is equivalent to a 220v circuit.
The milkshake itself is the equivalent to the Watts.

So, whether you chose a skinny straw or a fat straw, at the end of the day you've consumed the same amount of milkshake (Watts).

[Plate plinker]

Nice analogy razorfish.

[NyFirefighter357]

The real advantage of 220V on large loads is circuit wiring. 20amps needs 12ga wire. If you needed 40 amps for 110v circuit you would need 4ga wire and an equally sized neutral, which is more expensive and harder to through the walls. By using 2-12ga for 220v wires you can divide the amperage between the 2 smaller wires and of course don't need a neutral. And as the lengths get longer the wire needs to be larger.

[Mal Paso]

The real advantage of 220V on large loads is circuit wiring. 20amps needs 12ga wire. If you needed 40 amps for 110v circuit you would need 4ga wire and an equally sized neutral, which is more expensive and harder to through the walls. By using 2-12ga for 220v wires you can divide the amperage between the 2 smaller wires and of course don't need a neutral. And as the lengths get longer the wire needs to be larger.

8 gauge wire. 40 amps requires 8 gauge wire.

[dragon813gt]

8 gauge wire. 40 amps requires 8 gauge wire.

Yep, #4 will handle 70-95A depending on the wire type used.

[mvozz]

I think most of you have overlooked the MOST important reason to get 220V equipment of any kind - Lead pots, air compressors saws etc..... It makes it harder for other people to borrow it from you!!!:bigsmyl2:

[dragon813gt]

I think most of you have overlooked the MOST important reason to get 220V equipment of any kind - Lead pots, air compressors saws etc..... It makes it harder for other people to borrow it from you!!!:bigsmyl2:

Three phases fixes that problem permanently [emoji23]

[alamogunr]

I guess I'm a little out of my depth here. I always thought that 3 phase was an advantage in large electric motors, primarily in an industrial environment. Does it even work for resistive loads?

[dragon813gt]

Yes, it works in resistive loads. Amp draw is lower just like in motors.

[Catshooter]

alamogunr,

Yes, that's right. Electric heat is a resistive load so it starts gently and ramps up to full load. A motor is an inductive load and starts with violence (often six time the running current) and then tapers off to running load. In industrial environments there are engineering considerations that can make sense for using a three phase circuit for a heating load but power consumption isn't one of them.

As an example, the largest heat load I've ever seen is in a glass furnace. The furnace itself was square so they installed a four-phase 180/276 volt set up. One phase in each corner, arcing over to the other corner through the molten glass kept the glass liquid. Drew well over 10,000 amps. Since the furnace was square they needed four phases to arc over to each other. Made an X I suppose though of course you couldn't see it. If it had been triangular three would have been the way to go.

The poster with the pushing the car up the hill is actually a good analogy, but it only works for inductive loads as described above. Doesn't work for a heat (resistive) loads. Electricity is tricky stuff! :)


Cat

[alamogunr]

That is interesting. I retired from a factory that made conductors for amperage well over 10,000 amps but I never saw the actual application. I wouldn't be surprised if some of those products were used in that glass furnace.

[gwpercle]

No it doesn't. Watts are watts. 10 amps at 110 volts is 1100 watts. 5 amps at 220 volts is 1100 watts. There are lots of reasons for using 220 over 110. Reduced power consumption is not one of them.

You got that right ! Reduced power consumption is a misconception.

[Boogedy_Man]

My definition of using single phase against multiple phase, is that it is easier for two or three people to push a car up a hill than one large man to do the same thing.

240 is still a single phase in nearly all residential applications.

[Boogedy_Man]

The real advantage of 220V on large loads is circuit wiring. 20amps needs 12ga wire. If you needed 40 amps for 110v circuit you would need 4ga wire and an equally sized neutral, which is more expensive and harder to through the walls. By using 2-12ga for 220v wires you can divide the amperage between the 2 smaller wires and of course don't need a neutral. And as the lengths get longer the wire needs to be larger.

Some applications may still require a neutral....like ranges, dryers, etc...because there's still an unbalanced load.

The most conservative rating for allowable capacities in copper conductors (60 degrees C) puts 8awg at 40 amps, and 4awg at 70. Of course, there are situations where this would need to be derated, and other situations (such as welders) where smaller conductors could be used due to low duty cycle.

[Boogedy_Man]

alamogunr,

The furnace itself was square so they installed a four-phase 180/276 volt set up. One phase in each corner, arcing over to the other corner through the molten glass kept the glass liquid. Drew well over 10,000 amps. Since the furnace was square they needed four phases to arc over to each other. Made an X I suppose though of course you couldn't see it. If it had been triangular three would have been the way to go.

That's a polyphase setup I'd like to see...how was this power generated?

[Boogedy_Man]

Looking to buy a melting pot. Lot's of model come in either 110V or 220V. I have 220V readily available in my garage. What the benefit of one over the other?



OP...there could be a huge advantage depending on which code your home was built under, and how the electricians decided to design it.

In this area it is very common for homes to have a single 15A circuit for all garage receptacles and all required outdoor GFCIs...which in my opinion is an absolute disaster.

The 2014 code changed that practice, but many jurisdictions are still on much older code. I'm not up to speed on the 2017 code, but I believe there may have been even more conservative rules resulting from the popularity of electric cars.

The shorter answer is what you've already heard....if you have a 120V circuit that you can use without overburdening...there is no advantage.

[Boogedy_Man]

This discussion is all single phase 120/240 volt. A 20 amp 120v circuit max is 2400 watts, the recommended safe load is 80% or 1920 watts. 1440 watts for 15 amps. My old pot was 700 watts and the hot plate 1500 so I ran an extension cord from another circuit...

The 80% rule is for a single piece of cord and plug connected equipment that is not fastened in place. You can safely use 100% of a multiple outlet branch circuit, unless any portion of the load is a continuous load.

[Catshooter]

Boogedy Man,

The power was transformed. Three phase 26k incoming. The engineer called it two-phase! It was a very cool place to work in. Worked there three or four times over the years.

We were working underneath one of the furnaces one time that was running. Lots of steel support system and such. Man came in with us and put a Port a Band down on the ground. It had just had it's cord replaced. When he set it down the ground prong touched a steel support. The cord was still in a wrapped curl from the factory. Didn't take but about a couple of minutes and the cord was smoking. We slapped an Amprobe on it and the ground was drawing nearly 40 amps! Just a few loose killywiggles about.

The power to the furnace was run around three sides of the furnace in bussing. Two parallel runs of one inch by twelve inch aluminum plate, un-insulated. The busing was about eight feet up so you kinda wanted to watch were you were swinging a stick of conduit!


Cat

[sharps4590]

Cast, I've been an electrician for 42 years, passed my Masters Exam in '81. I would be tickled to death to see that furnace you're talking about. Certainly nothing like that around here unless something similar might be at MS&T in one of their labs. They do have some cool toys!

[Boogedy_Man]

Catshooter, that's pretty dang cool.

[Catshooter]

I'm a retired union wireman, worked in Seattle. Some pretty cool installations there.

I worked at Boeing's wind tunnel site quite a bit. Four point three acres, they had over 80,000 horsepower in electric motors. One was 55,000.

Their air compressor building has a 6,000 horse primary compressor. When they put it in in '64 is was a 5,000, but that was too small so they pulled it and had it re-wound to six. 4160 volt, across-the-line start! When that starter closed it sounded like a .30-06. In a quarter of a cycle it went from zero to over 3,000 amps. The operator told me that if the incoming voltage was less than 4.2, he'd call Seattle City Light and ask them to raise it. The motor would almost start at that voltage. If it failed he couldn't try again for eight hours so it could cool.

We replaced the 4 MVA transformer that fed that motor with a new 12.5 MVA unit. It weighed 1/3 of the old one. :)

Saw and worked on some cool stuff there.


Cat