I WAS absolutely gob smacked to discover this when I pulled out the fuses to a local fish and chip shop when called out to investigate a cable fault. The cartridge fuses for a 3-phase supply have been replaced with solid metal links. This can create a fire hazard should overloading or a short-circuit occur. Plus the solid link on the far right is undersized and likely not making good contact.
Similarly, in an all too common occurance I regularly find in homes, the same scenario is created in a Consumer Unit when a Circuit Breaker is changed for a higher rated breaker other than the one recommended. The cable becomes unprotected from overloading because the CB is unable to function correctly.
It's a good idea to check the main fuse in your meter cupboard to see if you have the correct rated fuse fitted to protect your installation. The main fuse acts as a back up to the main Circuit Breaker in the Consumer Unit. Fuses are rated in Amps, the rating of the fuse depends on the size of the cable it supplies. As a guide, in homes on the Costa Blanca generally you will find either a 32 Amp or 40 Amp main fuse for properties on a 5.75 kW tariff.