A man wears a face mask as he walks past a Wales souvenir store on October 19, 2020 in Cardiff, Wales. Wales will go into a national lockdown from Friday until November 9.Matthew Horwood | Getty Images News | Getty ImagesThe term “circuit breaker” has become common parlance in the U.K. in recent weeks, as the country searches for a way to curb the second wave of the coronavirus in a short, sharp way.The term was coined by scientific advisors to the British government who have recommended a two or three-week “mini lockdown. ” This time-limited set of strict restrictions would be designed to act as a “circuit breaker” to the infection rate, as the name implies.Northern Ireland was the first part of the U.K. to announce that a “circuit breaker” lockdown would start on Oct. 16 and last for two weeks. Meanwhile on Monday, Wales announced a similar lockdown that will come into effect on Friday and last until Nov. 9.Speaking at a press conference, Wales’ First Minister Mark Drakeford said the mini lockdown, what he called a “firebreak,” would be “a short, sharp, shock to turn back the clock, slow down the virus and buy us more time.”Scotland has already ramped up restrictions, and is reported to be considering a circuit breaker, whereas the U.K. government has still not decided whether to impose a mini lockdown on England to coincide with the half-term school holiday next week.What are circuit breakers?Essentially, circuit breakers are lockdowns but for a limited amount of time. They are designed to break the chain of infection, and bring the infection rate down. It’s hoped that circuit breakers will help to reduce pressure on health services as hospitalizations due to Covid-19 rise.This is crucial for the U.K., which has the third-highest number of coronavirus cases in Europe, with its tally now standing at just over 744,000 cases with 43,816 fatalities, according to data from Johns Hopkins University. It is currently battling a dramatic second wave of infections, like the rest of Europe, particularly in northern England.On Monday, 18,804 new daily infections were reported, up from 16,982 on Sunday. The seven-day average number of cases on Oct. 16 was 17,649, according to government data, compared to 14,588 a week before.Scientists advising the government seem to favor circuit breakers, as does the opposition Labour Party, with both encouraging the government to implement a mini-lockdown.Papers released last week showed that the Scientific Advisory Group for Emergencies (SAGE) — a group of leading scientists that provides scientific advice to the U.K. government at times of crisis — had advised the government to go further with the restrictive measures it had implemented (such as restricting social gatherings to six people and forcing bars and restaurants to close at 10pm).They first suggested a “circuit breaker,” or mini lockdown, a month ago and recommended banning households from mixing indoors and the closure of all bars, restaurants, cafes, gyms and hairdressers — essentially, a short-term repeat of the full lockdown seen earlier in the year.Do they work?Proponents of circuit breakers argue that although they won’t stop a virus in its tracks, they can suppress the spread of infections and buy governments and healthcare systems time to act. But while public health experts might advocate for them, business owners dread a return to lockdown.Still, the consensus among experts is that circuit breakers can play a part in curbing an epidemic.Speaking during a televised debate on Sunday on the merits of a short-term lockdown, Steven Riley, professor of infectious disease dynamics at Imperial College London, said that “we do need stronger restrictions if we want the number of infections to go down.”Matt Morgan, an intensive care unit consultant at the University Hospital of Wales in Cardiff, has warned that the U.K. health care system could be “on its knees” without action. He told CNBC that while he’s not an epidemiologist and can’t comment on the effectiveness of a circuit breaker, action was needed to take the pressure off hospitals.”What I do know is that the NHS struggles every winter so unless steps are taken to lessen the impact of Covid on all aspects of healthcare, it may become unmanageable,” he said.However, circuit breakers are not entirely straightforward. Within the same discussion, Professor Devi Sridhar, chair of global public health at the University of Edinburgh, added that due to the lag effect between infection and hospitalization of people with Covid-19, the effectiveness of a short lockdown would remain to be seen.”We would have to wait and see for indications that case numbers are coming down. This is why the testing and tracing system and surveillance is really important — to have a line of sight of how many people actually have the virus. If you wait to rely on hospitalizations and on deaths then it’s too late … they are lag indicators and we need lead indicators,” she said.Nonetheless, she said a mini lockdown was now inevitable in England. “It’s like a fire that’s raging, you can’t just turn your back on it and think it’ll go away.”A YouGov survey for Sky News published Monday showed that 67% of 1,781 people surveyed between October 15 and 16 back a circuit breaker lockdown.