What happens if I connect the electric cables in this way?

[shaft]

If I have a light bulb that take energy by the normal current of the house but I want connect at the bulb an other part of energy from an other source of electricity but with an inferior Voltage.
This circuit will work or no.
How to connect the second source of energy to reduce the amount of energy of the principale source

 

[f95toli]

There is no simple way of doing this safely, and you need a fair amount of equipment (it is of course possible, nearly every house with PV-cells on the roof will have the equipment)
The mere fact that you have to ask also means that you are not qualified do to it yourself.

 

[shaft]

it's just a theoretical question. I don't want kill myself .
I know that there should be something like an accumulator in the circuit between the second source of energy and the bulb . but I don't know if are necessary other parts

 

[berkeman]

If I have a light bulb that take energy by the normal current of the house but I want connect at the bulb an other part of energy from an other source of electricity but with an inferior Voltage.
This circuit will work or no.
How to connect the second source of energy to reduce the amount of energy of the principle source

it's just a theoretical question. I don't want kill myself .
I know that there should be something like an accumulator in the circuit between the second source of energy and the bulb . but I don't know if are necessary other parts

As f95toli says, this sort of thing is done with house-mounted photovoltaic power generation (merging that locally generated power with the utility's supply of AC Mains power). See these references for example, or use Google to find more...

http://energy.gov/energysaver/small-solar-electric-systems
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&sqi=2&ved=0CDEQFjAAahUKEwiIluza7IPJAhUB32MKHRdjDPo&url=http://www.nrel.gov/docs/fy04osti/35297.pdf&usg=AFQjCNF6gg5QDmnMg54CWRHb7p1ChADUJg&bvm=bv.106923889,d.cGc
http://www.dummies.com/how-to/content/the-essentials-of-photovoltaic-solar-power-for-you.html

.

 

[CWatters]

The regulations for this are usually very strict. Imagine there is a power cut. You don't want your "second energy source" bursting into flames as it tries to power all the houses in the area. Nor do you want to accidentally electrocute the engineer sent out to fix the cause of the power cut.

 

[anorlunda]

The safe way to do it is to have a second light connected to your solar/wind alternative source.

Do not attempt to connect alternate power sources In parallel with the mains power yourself. That could result in injury or death.