My 2p's worth - though, please note, I'm not a sparky...
and also how successful was it as a supply of mains power for the house. (kettle, lights etc)
You can't use it as an alternative power supply the house unless you isolate the house from the grid.
Just to expand on
@Ian Key's point.. connecting your V2L to the house, whilst the house is connected to the grid will most likely destroy your vehicles DC to AC inverter immediately.
And the onboard charger/converter is bidirectional, so will output 6kW+ if the V2L cable/plug has an appropriate resistor value. (Yes, it is rated to something like 2.2kW, but it will actually provide more).
I too saw some experiments on SpeakEV where greater power than the rated 2.2kW was achieved by using a non-standard resistor value in the discharge cable. Whether MG actually log discharge current and, if so, could use that to wiggle out of any future inverter failures is another question / concern
Our local electrical engineering company told me that, if mains power fails, the earth fails with it. So to make car battery powered house circuits safe, an earth spike driven into the ground has to be connected to provide an alternative.
That is correct assuming your house has the most-common UK configuration of a TN-C-S earthing arrangement. It is not the case if your house has a TT-earthing arrangement. The latter is often found in rural locations where power is delivered via overhead cables.
Either way, you will need a transfer switch, a suitable earth, an RCD, N-E bonding on the supply side of the RCD and ideally a 'critical loads' panel that will supply the necessary low-power appliances (such as light, computer, boiler, fridges etc.) but not the high power devices such as ovens or kettles that would overload the V2L output. In the UK, this work, of course, must be done to BS7671 regulations, ideally by a suitably qualified sparky or otherwise very competent person.
An example of how this can be achieved is detailed in this forum...
www.speakev.com
(Mods... I assume I can link to other forums from here? If not, please remove it).
I use an RCD first at the V2L adaptor, then run my extension lead to the heater.
Whilst it is safe to use the V2L adaptor to power doubly-insulated devices without additional protection, an RCD is necessary for devices which have an earth connection, as a typical convection heater would required. However, without also installing a suitable earthing arrangement and N-E bonding, the RCD will not trigger in the event of a fault condition.
IMHO, the better and safer way to power your house via the MG's V2L connection is to use the V2L output to charge the low-voltage (48V) batteries typically found on a home PV/ESS system. This can be simply achieved if your existing hybrid inverter has a generator input. Alternatively the use of an additional charger can be used to charge the inverter's batteries in parallel with the existing inverter. A few members on here have done that already. Another benefit of that configuration is that the home batteries become a 'buffer' storage and the power that can be drawn by the house will only be limited by the existing home inverter's output, rather than the 2.2kW of the MG4.
)
. Powers 2kW induction hotplate with ease.
