Brasilia is a planned city that was built in 5 years. One of the ideas was that each apartment quadra would be self-sufficient and supported by a commercial quadra; pharmacies, supermarkets, restaurants, shops, etc. While most of this is still valid, some of the commercial quadras have evolved into specialty product quadras.
One of these is the Rua das Elétricas at SHCS 109/110 in Asa Sul. Here you can purchase everything electrical from lamps, outdoor lighting, cables, light bulbs, LED lights and equipment, etc.
The prices are competitive and reasonable, and they also can give you advice on electrical problems.
Click on the map below and the location will open up on the Google Map browser.