There's probably nothing wrong with the heater. It draws 12 A and with the water heater and some other things (electric stove, dryer etc...) it may have indeed exceeded the service and blown that fuse. Buy two fuses and if it blows again don't run the heater. 60A is not a whole lot in this day of electric appliances.

I suspect highly that the 30A fuses (other than the water heater ones) are improper. Someone probably increased those size after blowing them prior.

Your cartridge fuse probably failed when a poor connection with the spring-loaded clip caused it to arc and spark until the fuse was destroyed.
However, the larger problem is that 30 amp screw-in fuses are much too big for your receptacle and lighting circuits. 15 or even 20 amps, depending on wire size, are the maximum permissible. Over-sized fuses were undoubtedly installed when the correct ones kept blowing, creating a well-known fire and safety problem, older houses not being wired for all the demands now being placed on electrical service.
This should be immediately addressed with, and rectified by, the building owner.

Whoever owns the place needs to do the correct "fix", which is to rewire it.

I strongly doubt that will happen.

What YOU need to do, NOW, is to go buy four 15A screw-in fuses and put them in place of the 30A ones. In the future, if these blow, it just means you're using more electricity than your house's wiring can handle, and that means you need to bug the landlord more loudly (or use less stuff)

Tell the owner to have a qualified electrician check and tighten all the terminals/connections within the panel.

As others have pointed out, the best fix is a rewiring job. You should definitely report the situation to the landlord. If he/she does nothing, there are a few things you can try.
In many older houses, people kept adding on to one circuit. This was particularly true in the case of knob & tube wiring. In many cases, the add-ons were for items of low power consumption items such as lamps, electric clocks, radios, etc., and posed little or no overload threat. Then along came microwaves, washing machines, countertop appliances, etc., which did pose an overload problem.
To get to the point, you MIGHT have one or two circuits that are overloaded, and sone circuits that are not. Perhaps one of those screw-in fuses is for a single receptacle for a window air conditioner. Since you wouldn't be using an A/C at the same time, perhaps you could plug in the heater there.
As pharkus wrote, immediately replace the top 4 screw-in fuses with 15A fuses. The circuits MAY be good for 20A, but the wiring size would have to be verified. It is highly likely there is NO WAY there should be 30A fuses in the top 4.
Once you replace all the fuses, including the 60A mains, remove the 15A fuses, one at a time, and see which lights and receptacles are not working. Keep a record of what is on each fuse. Maybe then you can determine if there is an underutilized circuit on which to use the heater.
At any rate, you are probably pushing the limits of this 60 amp service, especially with an electric water heater and another electric 240-volt appliance (if there is one. That is what the other cartridge fuse holder is for, possibly an electric range or dryer.)
Monitor closely. If the landlord does not address the situation, and you get the burning smell again, call the fire department. Seriously.

1. Get a propane heater.
2. Replace the 30 amp fuses, with 20 amp fuses....take notes about which circuits blow, and inform landloard.
I'm not a fan of 30 amp fuses....
3. Rewriring, is not what your landlord needs to do, he can replace the fusebox, (and use utility boxes). cost is likely somewhere around $120, if he knows enough to do it himself. The real reason things work better, is because he can then take the doubled up circuits and put them on their own breaker.

norman1964-
Why are you dredging up 3 year old threads?
I am sure the original poster has already addressed these issues YEARS AGO!

Norman just registered for these forums.