Residents were facing a nervous night on Saturday as fires continued to rage across Victoria following a day of record-breaking heat.

As the temperature soared above 40 degrees across the state, more than 300 fires broke out on Saturday.

Several homes were lost in a grassfire near Scotsburn, south of Ballarat, that burnt through more than 3000 hectares.

While a burst of rain slowed its progress in the afternoon, that Scotsburn blaze was one of a number that were still burning at 10pm as firefighters braced for a night of strong, changeable winds and continued heat.

At least one fire was allegedly deliberately lit, with a 34-year-old homeless man charged with reckless conduct endangering life, reckless conduct endangering serious injury and committing an indictable offence while on bail in relation to a fire at Epping on Melbourne’s northern outskirts.

He was remanded to face Melbourne Magistrates Court on Sunday.

More than 50 fire crews and four air tankers — including two from New South Wales — were battling the Scotsburn blaze on Saturday night, while watch-and-act alerts were still in force for fires near Wandin and Marysville.

There was little reprieve expected overnight, with the temperature not expected to dip below 30 degrees before midnight and a forecast wind change.

Earlier in the day, firefighters from three Country Fire Authority trucks survived two separate “burnovers” near Scotsburn. The officers were forced to retreat to their trucks as they became trapped by a fast-moving section of fire.

The firefighters turned on their trucks’ sprinkler systems and pulled down their protective heat shutters.

“They enacted their safety procedures that they’re trained for. They had a successful outcome and they went straight back out on the fire ground,” a CFA spokeswoman said.

Hundreds of firefighters were on the ground during the day, while more more than 50 aircraft – including Firebirds and Helitacks – attacked the blazes from above.

By 3.30pm on Saturday, emergency services had received more than 400 calls.

Among the blazes early in the day were two large fires in the outer reaches of Melbourne – in Wandin North and Epping.

Wandin North resident Geoff Riddle was at home when his view of the Yarra Ranges was suddenly obscured by billowing smoke.

Mr Riddle believed the fire started less than a kilometre or two from his house and four-hectare horse property in Cormilio Drive.

He enacted his fire plan, alerted his wife and rushed to move horses off the property.

As he moved one of the horses from a bottom paddock, it became clear that his property was under serious threat.

“I think the main thing is you really don’t understand what goes on until you experience it,” he said after the extreme danger had passed, and as a team of firefighters doused burning and blackened trees just over his boundary fence.

“It’s pretty daunting when you’ve got that wall of flames coming at your house. And you’ve got all your animals and your property. And everything’s there, and everything is in jeopardy, so it’s a bit of a worry.”

Authorities announced an emergency warning for Wandin North – a town of about 3000 people – just a few kilometres away from the blaze.

Shortly after, residents on the Warburton Highway in Wandin North could be seen hosing down rooftops.

Resident Matt Horton said embers more than 10 centimetres long landed on his property.

Mr Horton, a plumber, attached a rooftop sprinkler system to his house shortly after Black Saturday in 2009. The sprinklers were used on Saturday for the first time to protect against a bushfire, delivering a constant spray of water over the roof.

“Mate, it’s the first time I’ve turned them on for a fire. To be honest, hopefully it’s the last,” he said. Mr Horton said many residents left town when the fire started. “It was like a ghost town, everyone cleared out,” he said.

The emergency warnings were downgraded and the fire was contained on Saturday afternoon.

Meanwhile, 20 people were taken to hospital with heat-related conditions.

Paramedics were called to 50 heat-related cases throughout the day, as the temperature hit 41.2degrees in Melbourne at 3.20pm. The state’s highest temperatures were not far from Melbourne, with 45.1 degrees recorded at Avalon shortly after 3pm.

Despite the heat, four children had to be rescued from locked cars, frustrating authorities who had spent the week warning parents of the dangers.