Best Fuse For Fish Tank Heaters?

[techen]

So I got some heaters off someone but only one had a plug with no fuse in it. Now I know heaters are quite power eaters so am curious as to what kinda fuse I need to use with them.
 
At the mo I rewired one with a 13amp fuse in it and it's working. It's a 150watt heater, Is this safe or should I lower the amp fuse?
 
Also what kinda fuse amps would suit a 100 and 300watt heater.

 

[Lunar Jetman]

My 300W heater has a 3A fuse in it. As does my old 150W heater.

 

[techen]

That's all I needed to hear then, I'll stuff a 3A in it instead of a 13A

 

[RCA]

I believe it is about 3amps for stuff in water, but I am no electrician.  I got a heater once without a fuse in the plug when I bought a second-hand tank.  I decided to chuck the heater as I thought if it hasn't been working there is likely to be a problem.  Sad thing is, fish came with the tank!  Hopefully this is not the case with yours.

 

[techen]

The heater wouldn't work when I first opened it, He had wired it all wrong and so I rewired it, thrown a fuse in and it's now working. It looks brand new too, Lucky he didn't kill it with his bad wiring...

 

[RCA]

Phew...
 
I just know I had a power-head that kept blowing fuses so I put a 5amp in!  I was advised to return it to the 3amp and if it was blowing there was a reason!  Bit of a "muppet" thing to do really

.  Since bought a new power-head

to be on the safe side.  Water and electricity - hmmmm - I know we have to be careful.

 

[DrRob]

Watts = volts x amps. If you're in the UK you're 240V, so a 13 amp fuse will allow up to 3120W, or 3.12kW. For 300-400W you're fine with even 2 amp fuses as the fuse needed is Watts divided by volts, so 400\240=1.66666.

 

[RCA]

Great to know - cheers DrRob

 

[N0body Of The Goat]

Watts = volts x amps. If you're in the UK you're 240V, so a 13 amp fuse will allow up to 3120W, or 3.12kW. For 300-400W you're fine with even 2 amp fuses as the fuse needed is Watts divided by volts, so 400\240=1.66666.

 +1
 
So a standard UK 3W fuse should be used for anything upto 3x240volts (720Watts) in a UK standard 3-pin plug.