Had it a few times mainly on new builds, tend to have a more sensitive trip switch.
As suggested try different leads on seperate circuits or work without the heater (if you got one).
Had a similar problem albeit self inflicted earlier this week.
Doing an Indian restaurant floor midnight after it closed, using Powerburst but forget to add defoamer
.
Halfway through, waste tank full with alot of foam tripped out all the electrics, reset fusebox but foam had got into the vacs and kept tripping it. Luckily had my backup machine in the van so was able to finish off
Tested the next day at home and the vacs were fine, obviously dried out.
Moral - don't forget your defoamer :
