220 1 phase....grounded conductor?

[NetNathan]

Would you ground 1 side of a 220V control circuit to make a neutral?
I am doing a 110V control panel that has 3 pumps running at 480V 3 phase and 1 device that runs on 220V single phase. The plug calls for:
200-240VAC 50/60HZ
Pin1 = Phase 1 - L1
Pin2 = Neutral - N
Pin3 = Earth Ground - PE

I had intended on floating the 240V from a 1 phase 3KVA 480/240V Transformer. Is this a no-no??

 

[Aabeck]

NO! Both sides of a 220 circuit are hot & grounding will cause a direct short.

If you need a grounded neutral use a transformer or autoformer & ground one side of the transformer output, or the 0V potential lead of the autoformer.

 

[Bering C Sparky]

What is the "One Device" that will use the 220?

And by chance is this device from Europe or the like?

BCS

 

[LadderLogic]

If you need a grounded neutral use a transformer or autoformer & ground one side of the transformer output, or the 0V potential lead of the autoformer.

But isn't this what NetNathan is planning to do? He will have a separate 220V secondary winding on his transformer so he can ground one of the leads, can't he?

 

[NetNathan]

What is the "One Device" that will use the 220?

And by chance is this device from Europe or the like?

BCS

Yes, It is a Turbo Pump. It has its own controller and the controller requires 220 1 phase.

But isn't this what NetNathan is planning to do? He will have a separate 220V secondary winding on his transformer so he can ground one of the leads, can't he?

It is odd seeing the install manual call for 220V as L1 and neutral?
I assume I could ground 1 leg of the control transformer for the neutral side. It just seems odd, but I guess so would using a "floating" 220 as a control voltage.

 

[willxfmr]

Please contact an electrician to do the wiring for you. In my opinion that will be a LOT cheaper for you in the long run.

 

[BryanG]

Assuming that you are using an isolating transformer then you have no problem earthing one of the legs to create a neutral. If you wanted to add earth leakage protection you would have to earth one leg. Floating can be OK but you never know what voltage you have in respect to earth, and when there are other voltages in the same location it can lead to dangerous situations.

 

[shooter]

Yes put the Neutral on the 220 Volt side on gnd. To preserve a floating power, or you must use a isolationguard, to see when there is something wrong.

Check the internals of the pumpbox, when this 220 goes direct to a transformer or power supply check if you can change it to local power supply.
You must also check if the unit can handle the frequency 60Hz, as some contactor coils are designed to have only 50 Hz.
and/or motors.

 

[Bering C Sparky]

Yes, It is a Turbo Pump. It has its own controller and the controller requires 220 1 phase

It is odd seeing the install manual call for 220V as L1 and neutral?

I have never been or worked there, but I do work with many people from Europe. And from what I gather from them, this is how their power is set up, 220 each phase to ground with a neutral. (they dont use 120vac)

So if your device is European this does not supprise me at all. I am sure there are lots of folks out there that can confirm or deny this.

BCS

 

[Badger]

BCS we have many applications where 110vdc is not just the norm but in some cases the law. All civil, and industrial engineering hand tools have to be 110vac this includes any tool that has cables exposed to the operator. We use centre tapped transformers so if your body gets in between a hot wire and earth you get a 55vdc shock, this is deemed survivable, but I would not want to do it by choice.

 

[Bering C Sparky]

BCS we have many applications where 110vdc is not just the norm but in some cases the law. All civil, and industrial engineering hand tools have to be 110vac this includes any tool that has cables exposed to the operator. We use centre tapped transformers so if your body gets in between a hot wire and earth you get a 55vdc shock, this is deemed survivable, but I would not want to do it by choice.

__________________

That is interesting thanks for the input.
Our ship is set up the same way, we have 55vac on each leg to make up our 110v circuits. Only difference is that we dont use/have a neutral.

I must admit that we dont have any personnel from the UK on our vessels, most of the guys I work with from the other side of the Pond are from Norway, Denmark and Poland.

(Also have people from Veitnam, Philippines, Samoa, Micronesia, Mexico, and from all over Africa)

I have noticed that in their shops they all have 220volt hand tools such as grinders. Where if we have an American Tech they generally are using 110 volt stuff. (I just figured this was a cultrual thing, use what you are used to)

These guys all tell me that they dont have 110 in there homes and use 220 with a neutral.
(the ones from Norway, Denmark and Poland at least, some of the others describe some really scary scenarios about how their electrical is distributed through their homes)

Like I said, I have never been there so just going by what others tell me.

BCS

 

[osmanmom]

center-tap transformer ?

 

[NetNathan]

I have worked overseas a lot. They have 3 phase 380-415 and it is 4 wire, so they just grab 1 line and the neutral for their 220V form the 3 phase line. I have built panels for them and this is how I get the 220V control voltage also.
I have been an industrial electrician since the 70's....just never encountered actually making 240V with a grounded neutral. It will exist also with 115V control circuits, I will have to come up with a special color for the 220V neutral....I guess grey, I do not want to confuse it with the 115V neutral.

Would it be wrong to use a 2 pole circuit breaker for the device?

 

[NetNathan]

I fund my answer...in NEC
So it is okay to use 2 pole circuit breaker on the supply, just not fuses.

40.22 Grounded Conductor.
No overcurrent device shall be connected in series with any conductor that is intentionally grounded, unless one of the following two conditions is met:

(1) The overcurrent device opens all conductors of the circuit, including the grounded conductor, and is designed so that no pole can operate independently.

(2) Where required by 430.36 or 430.37 for motor overload protection.

 

[kallileo]

In Europe we have 230V where the neutral is grounded at the transformer so it used just a return path for the current. In some older installation it's possible to find neutral and ground to use the same wire but usually it's not allowed. Since we have one live wire we typically install single pole circuit breakers.
We ship a lot of machines to Us, South America and Japan we never ground any side of 200-240V control circuits and we never had any problems.