European appliances - is Neutral bonded to appliance chassis?

[Brian Martin]

I'm helping a friend in Europe understand if he can safely use a basic USA-type portable generator to power his European 240V 2-wire appliances which can accept 60HZ.
I think he needs to lift the usual USA generator center-tap neutral from generator chassis. And maybe bond the one 240V line which serves as Neutral in Europe. (if the USA generator has no features using 120V line-to-neutral power.

But I wonder:

1. Do most larger European 240V appliances have the one leg bonded to the appliance chassis.
2. Or, are both legs isolated/insulated from the chassis? (which would reduce the safety concern, I think) (If neither leg is bonded, that means the chassis becomes connected only by means of the earthing tab of a Type F “Schuko” plug when connected via a 3-wire cord...and chassis is total unconnected if using a 2-wire cord)

 

[Besoeker3]

This has an earth wire (ground). And for Europe it is 230V now.

 

[gene6]

IS Neutral bonded to appliance chassis?

No the neutral on house wiring is the same as in the Americas its 'floating'
A green/yellow EGC bonds all the appliance frames.

I'm helping a friend in Europe understand if he can safely use a basic USA-type portable generator to power his European 240V 2-wire appliances which can accept 60HZ.
I think he needs to lift the usual USA generator center-tap neutral from generator chassis. And maybe bond the one 240V line which serves as Neutral in Europe. (if the USA generator has no features using 120V line-to-neutral power.

This might work, but are you just wanting to plug in a 50hz 230V appliance to a 60 hz generator? If so i suspect you dont need anything other than a cord adapter. If your wanting to use the portable generator to back-feed fixed wiring there are other issues like RCD's and grounding.

But I wonder:

1. Do most larger European 240V appliances have the one leg bonded to the appliance chassis.
2. Or, are both legs isolated/insulated from the chassis?

Both are, the one catch is for built in 'surge protectors' in electronics might expect the voltage difference N-G to be close to 0 volts.

1. (which would reduce the safety concern, I think) (If neither leg is bonded, that means the chassis becomes connected only by means of the earthing tab of a Type F “Schuko” plug when connected via a 3-wire cord...and chassis is total unconnected if using a 2-wire cord)

Yes

 

[Brian Martin]

Thank you Besoeker3 and gene6 for the reply.
I wonder, is the following an accurate statement?
"We believe an unmodified USA-type portable generator can safely power most 2-wire 230V European appliances and loads which accept 50HZ and 60HZ if neither the ground nor the neutral on the USA-type generator is connected to the load, but the user remains responsible for any risks in safety or equipment damage."

 

[Besoeker3]

Thank you Besoeker3 and gene6 for the reply.
I wonder, is the following an accurate statement?
"We believe an unmodified USA-type portable generator can safely power most 2-wire 230V European appliances and loads which accept 50HZ and 60HZ if neither the ground nor the neutral on the USA-type generator is connected to the load, but the user remains responsible for any risks in safety or equipment damage."

I don't think the 230V is an issue. The different frequencies I'm not so sure about.

 

[Besoeker3]

Thank you Besoeker3 and gene6 for the reply.
I wonder, is the following an accurate statement?
"We believe an unmodified USA-type portable generator can safely power most 2-wire 230V European appliances and loads which accept 50HZ and 60HZ if neither the ground nor the neutral on the USA-type generator is connected to the load, but the user remains responsible for any risks in safety or equipment damage."

Cancel

 

[hbiss]

No the neutral on house wiring is the same as in the Americas its 'floating'

Are you saying that one side of your 230 is bonded to ground back at the panel like our 277? I hope so. And the appliances "float" the two hots with a separate ground?

If that's the case, as far as powering such appliances from a generator, I don't see a problem.

-Hal

 

[Brian Martin]

I suspect in Europe the Neutral is not bonded anywhere...but that's the big question, I think.
Is the Neutral NEVER BONDED in 230/400V 3PH systems?
Is the Neutral NEVER BONDED in 230V 1PH systems?
I see this: UK & EU wiring-single-phase-three-phase-distribution-board

Which of these 3 crude sketches attached depicts the best solution when attempting to use a USA-type sing phase generator in Europe?
Drawing A? B? C?

 

[Brian Martin]

For added clarity:
Is the Neutral NEVER BONDED (to Ground) in 230/400V 3PH systems?
Is the Neutral NEVER BONDED (to Ground) in 230V 1PH systems?
(not at Generator?)
(not at Main Panel?)
(not at Sub-panel?)
(not at load?)

 

[hbiss]

Which of these 3 crude sketches attached depicts the best solution when attempting to use a USA-type sing phase generator in Europe?
Drawing A? B? C?

I would suggest B as I assume it is what it would be connected to with the European power source.

-Hal

 

[ramsy]

Hal, he's trying to peddle electrical equipment not listed for the region, not similar L-G voltage, not similar earthing system, and without appropriate listing, much less instructions for compatibility.

TUV is a common testing standard used in Europe, similar to UL in the states, and much more rigorous than requirements for a CE mark.

 

[GoldDigger]

I would suggest B as I assume it is what it would be connected to with the European power source.

-Hal

I agree that the EU "neutral", which would be an NEC neutral in a 3 phase system, is generally bonded at the source (utility transformer) but is not rebonded in the customer wiring. The grounding conductor, PE = Protective Earth, is all that is connected to the load chassis and exposed metal parts. There may also be an assumption in some load device designs that one specific line conductor is not at a high potential with respect to earth.

I would NOT leave the generator output totally ungrounded, as that could lead to very high line to earth voltages under some fault situations (like an arcing ground fault.)

 

[Brian Martin]

Thank you for the knowledgeable input. At this point we are not selling USA Single Phase portable generators for Europe, because of the concerns that Ramsey raises. We are working with donated goods from Americans who want to send generators to Eastern Europe were power failures are becoming frequent. We had concluded, like GoldDigger, that we must not let the generator output totally ungrounded (like Drawing C) but rather do as he suggested (Drawing C).
Drawing A has some concerns, I think.
Therefore we are thinking Drawing B might be acceptable, and for 2 small (11kWe) PTO agricultural tractor-drive generators that we are shipping to Europe on Monday, we connected one Line to Generator Chassis. However, I am concerned if this might introduce an unexpected power potential between one Line and grounded earth terminals. (not necessarly unexpected voltage ptential, but unexpected current potential.

 

[Brian Martin]

(Sorry, I made a typo in prior post, here I corrected it-highlighted)

Thank you for the knowledgeable input. At this point we are not selling USA Single Phase portable generators for Europe, because of the concerns that Ramsey raises. We are working with donated goods from Americans who want to send generators to Eastern Europe were power failures are becoming frequent. We had concluded, like GoldDigger, that we must not let the generator output totally ungrounded (like Drawing C) but rather do as he suggested (Drawing B C).
Drawing A has some concerns, I think.
Therefore, we are thinking Drawing B might be acceptable, and for 2 small (11kWe) PTO agricultural tractor-drive Single Phase 220V 50HZ generators that we plan to ship to Europe on Monday, we connected one Line to Generator Chassis. However, I am concerned if this might introduce an unexpected power potential between one Line and grounded earth terminals. (not necessarily unexpected voltage potential, but unexpected current potential.

 

[drcampbell]

I think this needs to be answered by a local engineer and electrician, who are familiar with not only the local best practices, but also with the common local omissions, violations and cheats.

That said, I would definitely not leave the generator case ungrounded, nor rely on wood as an insulator. (especially outdoors)

I also wonder about the whole concept. I don't know what shipping costs are, but it seems that the cost of shipping is likely to rival or exceed the cost of the machine. Would it make a lot more sense to donate cash for people to buy locally-made machines?

 

[gene6]

I think this needs to be answered by a local engineer and electrician, who are familiar with not only the local best practices, but also with the common local omissions, violations and cheats.

They might be busy on the front lines, no harm in putting the info here on a easy to access public forum. (drawing B looks good)

I also wonder about the whole concept. I don't know what shipping costs are, but it seems that the cost of shipping is likely to rival or exceed the cost of the machine.

The shipping is likely free we have 747 freighters one after another departing regularly and loaded to capacity.

 

[gene6]

Hey Brian I am going to go with my original recommendation which is do nothing and don't suggest them alter the generator. You can protect a shuko then with a standard two pole 15 amp (USA) breaker, and just treat it like a US 240V receptacle. You could consider including whatever US NEMA twistlock cord cap is needed to plug into the generator and just make a 3 wire cord adapter from L1 and L2 to the Shuko, and ignore the Neutral.
Ideally if you can pre-wire the twistlock with a Brown, Blue, Green/Yellow (3 wire); extra hard service cord whip, where L1 = Brown, L2 = Blue and Green/Yellow is frame ground, ignoring the neutral.
If its a tractor PTO generator and it makes 60hz at 540 RPM tell them to run it a 450 RPM and they'll get 50 hz 240V. Keep the center tapped Neutral bonded to the frame just like any portable generator it will be fine.

 

[Brian Martin]

Thanks, drcampbell & gene6. Yes, we are also helping our friend get some 230V 50HZ portable gens from western Europe. Stock levels have gotten low, but found some, and if we do not find a satisfactory approach for USA gens, we'll focus on that. (we customarily set up larger industrial generators 20-2000KW for 230/400V 3PH 50HZ, so that's more straightforward).

gene6...if doing nothing with the neutral would work, there are lots of generators that could be donated and shipped to Europe. (for electrical loads that can accept 60HZ or 55 to 60HZ). But, wouldn't Drawing A apply and mean we need to add a warning label about 110V voltage potential from gen chassis to earth...if indeed EU Neutral is Bonded to Earth at nearby grid transformer or main panel? One of our top technicians with a motor background feels confident that Drawing B is the correct approach. He is usually right. But, until I find a WIRING DIAGRAM of a Euro 230V 2-Wire Portable generator, I have this uncomfortable feeling what if Euro portables have a grounding resistor or some unexpected configuration, and wat if the EU Neutral is commonly Bonded to Earth mostly far upstream at power station or a "communal transformer" at the other side of the village, and therfore the resistance is so high back to the bonded neutral so they rarely see faults currents to ground. Therefore, if we introduce a bonded Neutral on a generator chassis might it introduce a "surprise volt and power potential" between earth and generator chassis? And drcambells reference to "common local omissions, violations and cheats" is exactly part of my concern. One of my American acquaintances here who immigrated from Eastern Europe said "improvising" is very, very common. And our one lead technician cautioned me that I will likely get a different answer from each person I ask. But think if we do the wrong thing and damage an expensive item, or a gen causes a fatality, suddenly some answers would appear. So I am try to be prudent. But maybe I'm overthinking it or am off-track.

I am trying to get an Operator Manuals for the generators we are getting from Western Europe....hope that drawing will help...

 

[Brian Martin]

PS: We have to pay for the shipping...we're using ocean, so it will be several weeks. If those 747's have room for civilian, humanitarian aid, maybe we should check into it!

 

[drcampbell]

... But maybe I'm overthinking it ...

You don't have definitive, reliable answers yet.
Getting it wrong could cause death, destruction and mayhem.
You are performing ordinary due diligence. You are NOT overthinking it.

The shipping is likely free we have 747 freighters one after another departing regularly and loaded to capacity.

Who's paying for THAT?