Residents in the Al Rahmania area of Sharjah were left without power for about six hours on Monday and had to take shelter from the heat in neighbouring areas or shopping malls. The power went out at about noon and only returned in the evening.
Sharjah Electricity and Water Authority (Sewa) blamed the outages on "negligent excavation" by a construction company who hit one of their main supply lines.
"We have already restored the power and warned the company responsible not to repeat the act again," said a Sewa spokesman.
Residents said they had experienced no further problems.