Eleven trains -- two return services between Paris and London and seven trains between Brussels and London -- were cancelled.
Eurostar services had only just resumed after being suspended yesterday when another problem surfaced in the tunnel between Britain and France at around 10 am (GMT).
"Eurotunnel had another infrastructure problem, an electrical incident around 10 am this morning, and so they shut down the two tunnels from 10:00 am till noon," Eurostar's chief executive Nicolas Petrovic told AFP.
But the electrical incident caused further disruptions, adding to passenger woes after Saturday's fire had forced thousands to rearrange their travel plans.
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Passengers affected will be able to either exchange their tickets or get reimbursed, Petrovic said.
Some 400 trains and 1.5 million lorries pass through the tunnel every day.
Yesterday's fire forced all Eurostar trains already en route to turn back to their stations of origin, while 42 people were evacuated from the truck shuttle using the service tunnel.
Although the incident did not cause major damage, "there was a lot of smoke," said Denis Gaudin, an official from the northern French city of Calais.
The fire sparked travel chaos in Britain and France with long queues for refunds reported at London's St Pancras station.
In November 2012, a fire on a freight train halted traffic in the tunnel for two hours.
Four years earlier, a lorry fire caused major damage in the tunnel, affecting 650 metres of the structure and halting traffic for 30 hours.
John Taehan, a tennis coach with eight young players, had given up and was seeking an alternative route.