Utility giant SSE was making gains on Wednesday afternoon, providing a lift to the electricity sector in London, after announcing that it has hiked its gas and electricity bills for customers.Prices for SSE's household customers in the UK are to increase on average by nine per cent for both electricity and gas from the middle of October. The company, which also trades as Scottish Hydro and Swalec, said five million electricity customers and 3.4 million gas customers would be affected by the hike. Heading the other way were construction and materials stocks with FTSE 100 building materials distributor CRH registering losses after going ex-dividend - from today, investors will not have the right to the group's latest dividend payment.Infrastructure group Balfour Beatty was falling after Oriel Securities reduced its target price for the stock from 365p to 351p.Construction peers Kier and Galliford Try were also lower.Top performing sectors so far todayElectricity 8,398.25 +1.21%Bottom performing sectors so far todayConstruction & Materials 3,228.66 -2.86%Forestry & Paper 5,967.33 -2.72%Industrial Engineering 7,390.95 -2.60%Mining 17,978.50 -2.47%Life Insurance 4,562.02 -2.16%BC