220 volt hook up

[Jim Reinhard]

How do those of you that have machienes from other countries hooked up in the US.I have talked to alot of electricians.(I work in the construction trade) .And get a different answers to the same Question.My machine has 3 wires .They can be hooked up hot -hot -nuteral .or hot - hot -ground.Some of the electrcians say it has to be one way ,some say it has to be the other or its not safe.some say it dosent matter.

[Rich Harman]

The ground and neutral both connect to ground in the panel. I don't know what the code is. The ground wire can be a lighter gage than the others because in a 110v circuit it is not meant to carry current. Whichever way you do it make sure the wires are equal size, or make sure the smallest can carry the load.

And don't take my word for it, I'm not an electrician.

[Jim Reinhard]

Thats what I thought ,But If I look in my panel it dosent.The 3 main heavy wires coming in from the top do not ground.I have been told that white nuteral does ground somewhere but maybe back at the main conection.A nuteral has the ability to carry current and a ground does not.If they are both grounds then why do you need 2 of them .and what is the right one to use in this situation.I know for a fact that a water heater uses hot hot ground and a kitchen range has to be hot hot nuteral because it uses both 220 and 110 for the clock and electronics.So my thinking is this is like a kitchen range except for the fact that a laser uses a transformer to drop the voltage and a range does not.

[Richard Rumancik]

Jim, are you talking about your GCC laser or something else?

The kitchen range needs the neutral because there is 120VAC between neutral an each line, so line-line voltage is 240VAC (I know some people call it 110/220 but as far as I know USA is actually 120/240 as it is in Canada.) So on the range, you need the neutral so you can power the 120V components including the outlet for the coffee pot. There is no similarity between the range and laser that I see. The laser needs 240 only (250VAC typically in much of Europe/Asia).

(Lower power lasers shipped to NA can be run on 120VAC if they can be operated on a normal 15A circuit. They use power supplies which accomodate both voltages - the more modern ones switch themselves automatically rather than using a slide switch on the power supply. But at 50 laser watts or so you usually need to go to 240 or 250V input. The laser doesn't use what would normally be called a "transformer". It has a power supply (or two) that supplies low voltage to the mainboard and laser tube.)

If it is your laser you are talking about, does it not have a standard IEC 320 style inlet connector (like the back of a computer or monitor)? If so, these are wired with the centre pin as green-yellow ground.

The equipment manufacturer should be able to clarify any doubts about how to wire the equipment.

[Ross Moshinsky]

You should consult your instruction manual to find out if the machine needs a separate ground or not. I know a lot of Chinese machines are wired in a way where a separate ground stake needs to be installed to ground the machine. If that's the case, you could run 4 wire 220v and ground the machine at the box instead of in the ground. There are other things to look at such as the HZ though. US electrical runs at 60hz while Europe and maybe Asia runs at 50hz. Most machines are compatible with either 50 or 60hz, but it's something to look at.

[Jerry DePuma]

Hi Jim, If your machine runs on 220, the three wires would be two hot and a ground, two hots (ungrounded conductors) being one from either incoming phase. The incoming service from the utility usually does not have a ground conducter, the ground is usually some sort of electrode. Whether it be a cold water pipe, ground rods or a ufer (which connects to the rebar in a concrete slab or footer). Here in Arizona they require two ground rods because the soil is so dry, in NYC we used to use the water main from the street. Often in your residential main panel the neutral and the ground are on the same termination bar, in a commercial installation it should be separate with a bonding jumper.

The neutral is the return in a circuit which can carry current, the ground does not and should not carry current. As Richard stated in the electric range there are things that run on 110VAC the they would need a neutral but in that case there are usaully four conductors, two hots, neutral and a ground.

It's probably safe to assume that it's a ground wire but....

I always and as you should do in this case is double check with the manufacturer if there are any questions.

Jerry

[Rich Harman]

Here in Western, WA, where the ground is definitely not dry, we also are required to have two ground rods.

[Dan Hintz]

Although they do connect at the main entrance, ground and neutral should not be considered the same thing for the purposes of wiring remote boxes. You should have two hots and a ground running to your supply box... and don't forget to wrap the "neutral" (white) wire in electrician's tape at both ends to designate it as a hot line.

[Rich Harman]

In the case of my larger Shenhui, the power supplies for the logic and motion control can be switched between 110 or 220. However the power supply for the laser tube is 220 only. On the smaller machine (still 80 watts) the laser's power supply is 110.

[Richard Rumancik]

In the case of my larger Shenhui, the power supplies for the logic and motion control can be switched between 110 or 220. However the power supply for the laser tube is 220 only. On the smaller machine (still 80 watts) the laser's power supply is 110.

Hmmm - if you have only a single power cord wired to supply 240V, and the smaller (logic) supply was switched to run at 120V then I would assume that it would blow out as soon as the laser was turned on. Perhaps the switch is there as it is a multi-purpose power supply that can be used at 120 in some applications but not this one. It would be a kludge to have two power cords, and no good reason to do so.

[Richard Rumancik]

You should consult your instruction manual to find out if the machine needs a separate ground or not. I know a lot of Chinese machines are wired in a way where a separate ground stake needs to be installed to ground the machine. . . . .

I remember Rodne bringing this up with his machine and it struck me as an odd requirement. I wonder if it has to do with the pecularities (or inconsistencies) of power distribution in Asia. I would not have expected a piece of equipment installed in North America to need it's own ground rod. As well, I think it is legitimate to install a supplemental ground rod to your electrical system but am not so sure that it would be correct to run a "separate" ground rod independent of the building wiring. If there were some concern about the integrity of the main grounding system, a second electrode could be added, but I would expect that this should be tied to the main ground, not run as an independent ground. Does anyone have a schematic or explanation of why the Chinese laser manufacturer would ask for this?

[Rich Harman]

Hmmm - if you have only a single power cord wired to supply 240V, and the smaller (logic) supply was switched to run at 120V then I would assume that it would blow out as soon as the laser was turned on. Perhaps the switch is there as it is a multi-purpose power supply that can be used at 120 in some applications but not this one. It would be a kludge to have two power cords, and no good reason to do so.

There are two cords, one for the laser power supply, and one for the logic and motion power supplies. To lessen the chance of screw-ups I have them both on 220.

Having two cords can be handy. For instance you can easily wire it up so that the laser power supply turns on with the blower.

[Dan Hintz]

As well, I think it is legitimate to install a supplemental ground rod to your electrical system but am not so sure that it would be correct to run a "separate" ground rod independent of the building wiring. If there were some concern about the integrity of the main grounding system, a second electrode could be added, but I would expect that this should be tied to the main ground, not run as an independent ground.
This is exactly what I mentioned in that thread... if you do use a secondary ground (and I recommend against it), it must be bonded to the main ground.