What can happen to 220v Devices if I connect a 110V phase to both wires

[mjbalza]

Ok, i am new in this forum I am looking for some enlightenment. Today I got a call from my boss, which is now in Venezuela and he is connecting a 4000W 100v power plant at his condo. The electrician he found there connected a 2 Throw Switch Knife to the circuit to split the power coming from the electricity provider and the other side to the power plant. the issue for me and that I cannot understand is this.
The electrician connected the right side to the power coming from the city power which is 220V 2PHASE so is PH1 PH2 N,
the output is the same L1>L1, L2>L2, N>N, so far so good.
The generator side, as it it 110V and he wants to power the 110V devices on the both phases, he just split the 110v phase into the 2 PHASES of the switch, so L1>L1, L1>L2, N>N. So when the switch knife is connected to the generator side, the same 110v phase is connected to both the phases of the circuit. for the 110V devices connected there is no problem.
But my question here is:
What will happen with the 220v devices connected in the circuit? will affect them that the Lines are energized with the same phase?
or since there is no L2 the voltage will be 0 and wont affect the 220v devices?
I am worried for the AC units, dryer, etc wich uses 220V.
Can some one explain if this is Safe?
Can also a Automatic Transfer Switch be used instead with this configuration?

https://www.amazon.com/Automatic-Transfer-Electrical-Selector-Switches/dp/B07RQVDJ71

 

[brianmoooore]

I'm in the UK, where 2 phase supplies are unusual in general, but quite common in the rural area that I am in, and have connected 230 volt single phase generators to a 230-0-230 volt systems.
The 460 volt items, if they are truly that, with no neutral connection, simply will not work. This is the 220 volt stuff in your set up.
The 230 volt items, in my case (the 110 volt ones in yours) will work as normal, BUT it's important to check that the any neutral conductor that is common to devices which are on differing phases, is capable of carrying the current, which will now be the sum of the current drawn by the devices, rather than the difference between them.

 

[Lucien Nunes]

The 220V equipment will not function but will still be live with 110V on both wires, so hazardous to touch even though it seems dead. This can be a trap for the unwary.

But as Brian says, the only real electrical problem likely to arise is if any circuits share a neutral between 110V loads on both phases, as the current in the neutral will be the sum of the two phase currents instead of the difference between them, and the neutral cable might be overloaded. Individual 2-wire 110V circuits will be fine.

 

[mjbalza]

I'm in the UK, where 2 phase supplies are unusual in general, but quite common in the rural area that I am in, and have connected 230 volt single phase generators to a 230-0-230 volt systems.
The 460 volt items, if they are truly that, with no neutral connection, simply will not work. This is the 220 volt stuff in your set up.
The 230 volt items, in my case (the 110 volt ones in yours) will work as normal, BUT it's important to check that the any neutral conductor that is common to devices which are on differing phases, is capable of carrying the current, which will now be the sum of the current drawn by the devices, rather than the difference between them.

Thanks for your quick reply. There is no Neutral connections in the 220V circuit. So I know now they are safe. Thanks a lot

 

[mjbalza]

The 220V equipment will not function but will still be live with 110V on both wires, so hazardous to touch even though it seems dead. This can be a trap for the unwary.

But as Brian says, the only real electrical problem likely to arise is if any circuits share a neutral between 110V loads on both phases, as the current in the neutral will be the sum of the two phase currents instead of the difference between them, and the neutral cable might be overloaded. Individual 2-wire 110V circuits will be fine.

Understood! I just found this very weird LOL. I have never seen this before. But seem to be usual when using single phase generators.