240V L-N vs. 240V L-L

[Nutmegger]

As we know, with the American 240V L-L voltage system, a 12AWG two-wire circuit can deliver (non-continuously) 4,800W.
In Europe, they have 240V (well, 230V) L-N.
Does it mean that a 12AWG circuit in Europe can also sustain 4800W, or does L-N work differently in that regard?

 

[SceneryDriver]

As we know, with US 240V L-L voltage system, a 12AWG two-wire circuit can deliver (non-continuously) 4,800W.
In Europe, they have 240V (well, 230V) L-N.
Does it mean that a 12AWG circuit in Europe can also sustain 4800W, or does L-N work differently in that regard?

It would most likely be a 16A circuit so you could draw 3840W (240V * 16A). The math still works the same on the other side of the pond though. W=VA.



SceneryDriver

 

[mbrooke]

As we know, with US 240V L-L voltage system, a 12AWG two-wire circuit can deliver (non-continuously) 4,800W.
In Europe, they have 240V (well, 230V) L-N.
Does it mean that a 12AWG circuit in Europe can also sustain 4800W, or does L-N work differently in that regard?

L-N would be the same wattage wise, ie 230 volts at 20amps 4,600 watts be it derived from L-N or L-L.


FWIW however wire size in Europe is different. A 20amp circuit in Europe is typically wired in 2.5mm2, where in the US #12 translates to 3.31mm2. A 16 amp circuit (their version of the 15 amps circuit) is usually done in 1.5mm2 where our #14 is 2.08mm2. There are also 10amp circuits in places like Switzerland and Eastern Europe. In the UK a ring system is used where 2.5mm2 wire is literally run in a loop with both ends (two hots) landing on the same 32 amp breaker. Because of the higher rating, UK plugs have individual fuses inside of them to protect the cord. This method was developed after the war to save on copper.




If we were to adjust #14 and #12 to European codes under similar conditions the same wire would be rated about 18.5 amps and 25 amps respectively.

 

[ActionDave]

As we know, with the American 240V L-L voltage system, a 12AWG two-wire circuit can deliver (non-continuously) 4,800W.
In Europe, they have 240V (well, 230V) L-N.
Does it mean that a 12AWG circuit in Europe can also sustain 4800W, or does L-N work differently in that regard?

L-L or L-N makes no difference, voltage is voltage, amps is amps and watts is watts. A motor or heater or anything else only knows or cares what the voltage is not what part of the electrical system is used as a neutral unless you get into some sophisticated electronic equipment.

 

[Nutmegger]

L-L or L-N makes no difference, voltage is voltage, amps is amps and watts is watts. A motor or heater or anything else only knows or cares what the voltage is not what part of the electrical system is used as a neutral unless you get into some sophisticated electronic equipment.

So, to clarify... Then the reason why we can't get 4800 watts out of a 120-v L-N circuit is because it would take 40 amps to deliver that amount of power? So, at the risk of sounding really dumb: does it then mean that the overcurrent protection really *is* about limiting the current flowing through the conductors, and not the power delivered by them?

 

[ptonsparky]

So, to clarify... Then the reason why we can't get 4800 watts out of a 120-v L-N circuit is because it would take 40 amps to deliver that amount of power? So, at the risk of sounding really dumb: does it then mean that the overcurrent protection really *is* about limiting the current flowing through the conductors, and not the power delivered by them?

Yes, the power would then be dependent on the voltage applied. P=IE

 

[Besoeker]

As we know, with the American 240V L-L voltage system, a 12AWG two-wire circuit can deliver (non-continuously) 4,800W.
In Europe, they have 240V (well, 230V) L-N.
Does it mean that a 12AWG circuit in Europe can also sustain 4800W, or does L-N work differently in that regard?

Yes, in UK it's 230V_LN single phase for the vast majority of domestic installations.
Receptacles are, for the most part, 13A or about 3kW on a resistive load. Plugs are fused at 13A max.
We don't use AWG. Metric (SI) sizes for example 2.5mm²

Typical installation.

Other countries in Europe have different practices.

 

[Tony S]

Yes, in UK it's 230V_LN single phase for the vast majority of domestic installations.


Other countries in Europe have different practices.

Fortunately it’s 230V -6% +10%. The supply companies did nothing when the IET and the IEC decided to harmonise european supply voltages. Basically the IET and the IEC were told where to go.

I’ve just checked my supply, it's 248V

 

[Besoeker]

Fortunately it’s 230V -6% +10%. The supply companies did nothing when the IET and the IEC decided to harmonise european supply voltages. Basically the IET and the IEC were told where to go.

I’ve just checked my supply, it's 248V

Yes, I should have said 230V nominal.

 

[ActionDave]

Yes, in UK it's 230V_LN single phase for the vast majority of domestic installations.
Receptacles are, for the most part, 13A or about 3kW on a resistive load. Plugs are fused at 13A max.
We don't use AWG. Metric (SI) sizes for example 2.5mm²

Typical installation.

Other countries in Europe have different practices.

Fortunately it’s 230V -6% +10%. The supply companies did nothing when the IET and the IEC decided to harmonise european supply voltages. Basically the IET and the IEC were told where to go.

I’ve just checked my supply, it's 248V

Yes, I should have said 230V nominal.

Thanks guys, for completely ignoring the context of the OPs question and cluttering up his thread. While your at it why not fill us in on what a typical breakfast is like for you all.

 

[Besoeker]

Thanks guys, for completely ignoring the context of the OPs question and cluttering up his thread. While your at it why not fill us in on what a typical breakfast is like for you all.

I did. Mostly you can have up to only 3kW, not 4.8 kW and, as I said, we wouldn't use AWG.
I don't know what else you would expect/accept by way of an answer.

 

[ggunn]

...does it then mean that the overcurrent protection really *is* about limiting the current flowing through the conductors, and not the power delivered by them?

Yes. OCP is there to protect the insulation from softening due to heat generated in the wire, and that heat is proportional to the square of the current flowing through the wire. For a given amount of power the higher the voltage the lower the current.

 

[JFletcher]

So, to clarify... Then the reason why we can't get 4800 watts out of a 120-v L-N circuit is because it would take 40 amps to deliver that amount of power? So, at the risk of sounding really dumb: does it then mean that the overcurrent protection really *is* about limiting the current flowing through the conductors, and not the power delivered by them?

You can get 4800W from a 120V circuit, you'd just need conductors and OCPD capable of delivering it. Normally at that wattage we'd be on 240V, tho we run 9.6+kW (9600W; double the 4800W) appliances on 240V (double the 120V).

There is a NEMA 5-50 receptacle for 120V 40-50A applications:

http://www.cooperindustries.com/con...le_50a_125v_nema_5_50_2_pole_3_wire_1253.html

 

[Nutmegger]

Thanks all...
That cleared a long-time misconception for me. So, it is about lower current needed at a higher voltage, and it's not about the amount of power being delivered.
With that, it means that if the US residential electrical system ran on 240V line-to-neutral, like in Europe, we would just need 14 AWG where 12 is used, 12 in place of 10, and so on.
Wow, we would have saved save a lot of copper :happysad:

 

[Besoeker]

Thanks all...
That cleared a long-time misconception for me. So, it is about lower current needed at a higher voltage, and it's not about the amount of power being delivered.
With that, it means that if the US residential electrical system ran on 240V line-to-neutral, like in Europe, we would just need 14 AWG where 12 is used, 12 in place of 10, and so on.
Wow, we would have saved save a lot of copper :happysad:

Yes, possibly so.
A slight digression - mods be kind.
You operate some things at 240V and, as mentioned by another member, the appliance most likely won't care whether it's 240V_LL or 240V_LN.
Mostly your residential supplies are, as far as I know, 120-0-120V. Lighting is 120V and heavy duty appliances like washing machines are typically 240V.
We have just 230V for everything. I think it makes the system simpler and you don't have the potential hazard of a lost neutral imposing up to 240V on something rated for 120V.

 

[oldsparky52]

Thanks guys, for completely ignoring the context of the OPs question and cluttering up his thread. While your at it why not fill us in on what a typical breakfast is like for you all.

I found the information they shared interesting, and personally, I'm glad they did share.

 

[Besoeker]

I found the information they shared interesting, and personally, I'm glad they did share.

Very kind of you.
I supposeI have a foot in both camps.
I'm a Brit (not English) and my dear wif is American but not a Yank.

 

[gadfly56]

Yes, possibly so.
A slight digression - mods be kind.
You operate some things at 240V and, as mentioned by another member, the appliance most likely won't care whether it's 240V_LL or 240V_LN.
Mostly your residential supplies are, as far as I know, 120-0-120V. Lighting is 120V and heavy duty appliances like washing machines are typically 240V.
We have just 230V for everything. I think it makes the system simpler and you don't have the potential hazard of a lost neutral imposing up to 240V on something rated for 120V.

A good point. It seems once a month or so we have someone posting symptoms that indicate a lost neutral. If you're really lucky, the two phases are balanced enough to prevent disaster, but I wouldn't hang my hat on it.

 

[gadfly56]

Very kind of you.
I supposeI have a foot in both camps.
I'm a Brit (not English) and my dear wif is American but not a Yank.

If I recall correctly, like my wife she is a "Grits"; Girl Raised In the South.

 

[mbrooke]

Thanks all...
That cleared a long-time misconception for me. So, it is about lower current needed at a higher voltage, and it's not about the amount of power being delivered.

That would be correct. You need double the current at 120 volts. Similarly, at 480 volts you would need 1/4 the current compared to 120 volts. One place where this can be seen are multi tap HID ballasts, as you go up in voltage taps, current goes down.

With that, it means that if the US residential electrical system ran on 240V line-to-neutral, like in Europe, we would just need 14 AWG where 12 is used, 12 in place of 10, and so on.
Wow, we would have saved save a lot of copper :happysad:

Also right. Homes would need half the circuits. Per code a 2000 square foot home needs 4 15 amp or 3 20amp 120 volt general use circuits (3va per foot calc). At 240 volts you would need only two 15 amp general use circuits. One 20 amp small appliance branch circuit (or two 15s) and one 15 amp washer circuit.