What means t250l 250v on the glass fuse?

The markings "T250L" and "250V" on a glass fuse indicate its specifications. The "T" signifies that it is a time-delay fuse, which allows for temporary overload conditions without blowing immediately. The "250V" indicates the maximum voltage rating the fuse can handle safely, meaning it can be used in circuits with a voltage of up to 250 volts. The "250" typically refers to the current rating, expressed in milliAmperes (mA), which in this case is 250 mA.