Aluminium cable wire for domestic electric load supply
I have recently finished my house construction. In which preliminarily I applied my house for a electric load of 1 KW (commercial) Single Phase supply for the usage of various electrical tools during construction. The electricity board supplied this through single core 4 sq mm aluminum service cable wire connection from the main pole. After I permanently resided to my house I opted for a load increase to 5KW (domestic) supply. But during usage of various appliances in home I found very low voltage often which made running heavy appliances like AC, water geysers and microwave ovens difficult.
Then I filled a request for increase in service wire guage increase. The board supplied me now with 8 sq mm single core aluminium cable wire. After this for few months everything went good and I got good voltage (~220 - 230V). But recently I started getting low voltage again.
Is this still because of the aluminium cable or is it normal to get low voltage around this time since its peak summer time now? Is 8 sq mm aluminum wire enough for home if run almost 5000 Watt load?