What fuse should I use on a 10.4kW shower?

Question

The fuse in my electric shower recently burnt out. It was a 45A fuse. I have 10.4kW electric shower with 10mm cables connected to 240Volt UK domestic mains suply. The power cables from the shower connect in to a rip cord switch box which is subsequently connected to an independent fuse box which used to have a 45A fuse in it until it burnt out. I replaced the burnt out fuse with a brand new 45A fuse. Since then, when I turn my shower on the water does NOT get as hot as it used to with the old fuse. I have to turn the temperate dial up by at least three points before the water gets warm enough. Why is this happening? Should I actually fit a 50A fuse so more load is drawn from the mains? I don't under what the problem is. Can someone qualified in electronics advise me?

Answer 1

The fuse has actually nothing to do with your problem.Going higher runs a risk of fire.It sounds as the problem is in the heating element itself likes it burning out. Leave the fuse alone and check the heating elements out. Good luck

Answer 2

The original fuse burned out for a reason. It may be that you had a low water condition in your water tank, exposing a heating element to the air. The heating element will burn up when this happens, which may have also caused your fuse to burn out.

If your water tank has more than one heating element, the other elements probably don't generate enough heat, causing your problem. Putting a larger fuse in your circuit will not cause more current to flow.

You definitely need to check your heating elements. Disconnect them one by one and measure resistance with an ohmmeter. Besides reducing the heating capacity of your shower, a burned out heating element may pose a safety risk because the conductor inside the element may be exposed to the water.

Answer 3

First goal should be to find out why old fuse burned. There must be something in the system that led to over current and failure of the fuse. That condition still exists and perhaps is the reason for less than normal performance.
Another thing to check is to see if any other point of wire or fuse contactor have gone bad due to previous over current condition leading to more resistance and dissipation in the supply lines. Hope this helps.

Answer 4

well...first off having the heater wired with #10 copper...means your circuit breaker or fuse (per NEC code and depending on wire insulation type) usually should handle no more than 30-35 amps of current. Putting more load on the wires(current) will only lead to the insulation melting and causing a fire. as far as your 10.4kw which broken down to 220 volts should draw aprox 25-30 amps...which also makes sense...so the bottom line is sure go ahead continue to use the 45 amp fuses (or higher) and your problem will be gone soon.....oh yea as well as your house...
otherwise use only 35 amp fuses max(electrician of 30 yrs)