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[Doctor Gollum]

Maths was based on the following...

(square root of 3)1.73 x 32A x 240V = 13,286.4Wh or 13.29kWh

So to charge 93kW would take 7 hours.

22kWh would require a current of 53A which is somewhat optimistic for a domestic supply, even three phase.

Yes, its wrong!

Its 3 phase so 1.73 x 32 x 400 = 22kW power available 

Ah OK if the current is lower, the voltage has to be increased to output. Makes a bit more sense

[LC0112G]

Maths was based on the following...

(square root of 3)1.73 x 32A x 240V = 13,286.4Wh or 13.29kWh

So to charge 93kW would take 7 hours.

22kWh would require a current of 53A which is somewhat optimistic for a domestic supply, even three phase.

Why root 3? The correction you're applying is already accounted for in the 240V RMS calculation of voltage.

Most normal houses only have single phase, and the supply is typically fused at 60A. Flats can be 30A, but if you're living in a flat on the 12th floor of Nelson Mandela house then charging an EV is going to be problematic anyway. You can ask for the 30A/60A to be upgraded to 80A or 100A on a single phase.

A 22Kw wall charger does require 3 phase. Again you can ask to be upgraded. I suspect the local distribution grid is going to struggle though if/when every house in a street wants it.

root 3 is used for 3 phase power calcs as you don't actually get '3' times the power when its a 3 phase machine in delta wiring (you can in star but then the voltage is lower), but the voltage is 400 not 230 

Yes, I know, that's why I said the root 3 bit is already taken into account in the 240V RMS. 400V / root(3) = 230.9V.

[Kevin Wood]

Maths was based on the following...

(square root of 3)1.73 x 32A x 240V = 13,286.4Wh or 13.29kWh

So to charge 93kW would take 7 hours.

22kWh would require a current of 53A which is somewhat optimistic for a domestic supply, even three phase.

Why root 3? The correction you're applying is already accounted for in the 240V RMS calculation of voltage.

Most normal houses only have single phase, and the supply is typically fused at 60A. Flats can be 30A, but if you're living in a flat on the 12th floor of Nelson Mandela house then charging an EV is going to be problematic anyway. You can ask for the 30A/60A to be upgraded to 80A or 100A on a single phase.

A 22Kw wall charger does require 3 phase. Again you can ask to be upgraded. I suspect the local distribution grid is going to struggle though if/when every house in a street wants it.

root 3 is used for 3 phase power calcs as you don't actually get '3' times the power when its a 3 phase machine in delta wiring (you can in star but then the voltage is lower), but the voltage is 400 not 230 

Yes, I know, that's why I said the root 3 bit is already taken into account in the 240V RMS. 400V / root(3) = 230.9V.

It's all irrelevant because the diversity used in sizing the substation that feeds your housing estate means it'll soon explode if every property draws 22 kW for most of the night.

[Kevin Wood]

.. and then there's the heat pumps we're all told we'll need when they ban gas boilers.

[STEMO]

When are the idiots who keep pedalling all of this utopian shite going to realise that it's a physical impossibility to have the infrastructure needed to implement their vision ready in time?
It's quite scary to hear this nonsense roll off their tongues when, surely, deep down, they know it just can't happen. Who, in a position to be heard, is going to call them out? It's like the wokes, who have managed to quieten any form of contradiction. No one is arguing against this unachievable timescale. Why?

[STEMO]

It seems like they are hoping, rather then doing any actual planning.

[Field Marshal Dr. Opti]

It seems like they are hoping, rather then doing any actual planning.

They have virtue on their side. They are good people.

[Doctor Gollum]

It seems like they are hoping, rather then doing any actual planning.

They have virtue on their side. They are good people.

The opps they are. They're the exact polar opposite of good people.

[Raeturbo]

They are but they have the loudest voices somehow??🤷‍♂️

[Nick W]

It seems like they are hoping, rather then doing any actual planning.

They are politicians who are deliberately educated to have no knowledge, competence or expertise in anything useful. They are then trained to think that six months is far enough in the future for anything they say, or decisions they can't avoid, to be forgotten. And don't forget the career progression: don't opps up anything too public so their post politics executive directorship or public speaking scams are still possible.


Then there is the general public, who either aspire to be hopeless dreamers or are ill-informed imbeciles who are the definition of confirmation bias. It's depressingly common to find both these traits together, and in politicians - Liz Truss is the current example.

[Raeturbo]

I agree 👍

[Marks DTM Calib]

Maths was based on the following...

(square root of 3)1.73 x 32A x 240V = 13,286.4Wh or 13.29kWh

So to charge 93kW would take 7 hours.

22kWh would require a current of 53A which is somewhat optimistic for a domestic supply, even three phase.

Why root 3? The correction you're applying is already accounted for in the 240V RMS calculation of voltage.

Most normal houses only have single phase, and the supply is typically fused at 60A. Flats can be 30A, but if you're living in a flat on the 12th floor of Nelson Mandela house then charging an EV is going to be problematic anyway. You can ask for the 30A/60A to be upgraded to 80A or 100A on a single phase.

A 22Kw wall charger does require 3 phase. Again you can ask to be upgraded. I suspect the local distribution grid is going to struggle though if/when every house in a street wants it.

root 3 is used for 3 phase power calcs as you don't actually get '3' times the power when its a 3 phase machine in delta wiring (you can in star but then the voltage is lower), but the voltage is 400 not 230 

Yes, I know, that's why I said the root 3 bit is already taken into account in the 240V RMS. 400V / root(3) = 230.9V.

Er no......its root 2 (0.707 as we use) to get from peek to RMS as peek mains (Line to Neutral) is 325V

With three phase, having waveforms which are 120 degrees out of phase with each other, the line to line volts is greater at 400V RMS, line to neutral is still 230V

Simples!

So with a 3 phase supply you can either operate 230V (Line to neutral) or 400V (Line to Line).

[Rangie]

Wow all sounds very complicated, I'll stick with Sainsbury's pumps, just have to choose petrol or diesel...

[Marks DTM Calib]

Wow all sounds very complicated, I'll stick with Sainsbury's pumps, just have to choose petrol or diesel...

The man on the street just needs to know it bites if you touch the live and bites more if you grab two lives on a 3 phase setup 

[LC0112G]

Maths was based on the following...

(square root of 3)1.73 x 32A x 240V = 13,286.4Wh or 13.29kWh

So to charge 93kW would take 7 hours.

22kWh would require a current of 53A which is somewhat optimistic for a domestic supply, even three phase.

Why root 3? The correction you're applying is already accounted for in the 240V RMS calculation of voltage.

Most normal houses only have single phase, and the supply is typically fused at 60A. Flats can be 30A, but if you're living in a flat on the 12th floor of Nelson Mandela house then charging an EV is going to be problematic anyway. You can ask for the 30A/60A to be upgraded to 80A or 100A on a single phase.

A 22Kw wall charger does require 3 phase. Again you can ask to be upgraded. I suspect the local distribution grid is going to struggle though if/when every house in a street wants it.

root 3 is used for 3 phase power calcs as you don't actually get '3' times the power when its a 3 phase machine in delta wiring (you can in star but then the voltage is lower), but the voltage is 400 not 230 

Yes, I know, that's why I said the root 3 bit is already taken into account in the 240V RMS. 400V / root(3) = 230.9V.

Er no......its root 2 (0.707 as we use) to get from peek to RMS as peek mains (Line to Neutral) is 325V

I never said any different? DG didn't mention peak voltages? Yes root two applies when converting peak single phase to neutral voltages to RMS.

With three phase, having waveforms which are 120 degrees out of phase with each other, the line to line volts is greater at 400V RMS, line to neutral is still 230V

Simples!

So with a 3 phase supply you can either operate 230V (Line to neutral) or 400V (Line to Line).

Yep, but I was asking why DG had included root 3 in a 240V calculation. I assumed it was related to 3 phase (since that's where it usually crops up) You either use 240V as is, or 415V and root 3.

The whole point of RMS voltages it so allow you to calculate powers easily (for resistive loads anyway).