What fuse for 600W oil radiator?

[AlexC1981]

Hi All,

I have a dinky 600W oil radiator that has just blown its 3A fuse. It's only had around 30 hours or so use.

The internet says a 3A fuse is suitable for up to 750W. Should I put another 3A in it or get a 5A? The cable looks up to it as it is pretty thick.

Thanks.

[kev b]

Put another 3A fuse in, if it blows again you have a fault and the heater needs checking by a qualified person.

[softtop]

kev b said:

Put another 3A fuse in, if it blows again you have a fault and the heater needs checking by a qualified person.

Any more than 3A and you are moving the problem.

[AlexC1981]

I'll try that then cheers.

[Deva Link]

I'd put a 5A fuse in - 3A fuses are ridiculously fragile and it'll be weakened by the surge current as the heater is turned on.

As you suggest, the fuse is only there to protect the mains lead anyway.

[Cupramax]

Deva Link said:

the fuse is only there to protect the mains lead anyway.

you are kidding aren't you... I do hope so.

[caziques]

Yep, the fuse is to protect the lead from the plug to the heater - as this is probably 1mm sq a 5 amp fuse would be OK as well.

Think yourself lucky - no fuses in New Zealand plugs, the lead would be protected by a 20amp breaker on the main board!

[spikeyhead]

Fuses are about the worst possible form of electrical protection known. If you don't believe me, check a fuse spec to see how long a 13A fuses takes to blow with 14A going through it.

[Deva Link]

Cupramax said:

Deva Link said:

the fuse is only there to protect the mains lead anyway.

you are kidding aren't you... I do hope so.

As caziques points out, if the fuse is too big (or there isn't one) then the lead itself become the fuse - and will overheat and melt. So the right fuse in the plug prevents this from happening, and you can size the fuse according the current carrying capability of the lead.

If the appliance itself requires more precise protection such as electronic equipment would, then it'll have it's own internal fuse.

[Deva Link]

spikeyhead said:

Fuses are about the worst possible form of electrical protection known. If you don't believe me, check a fuse spec to see how long a 13A fuses takes to blow with 14A going through it.

I'd be amazed if it ever blew at 14A (in normal ambient temperatures).

[spikeyhead]

Deva Link said:

spikeyhead said:

Fuses are about the worst possible form of electrical protection known. If you don't believe me, check a fuse spec to see how long a 13A fuses takes to blow with 14A going through it.

I'd be amazed if it ever blew at 14A (in normal ambient temperatures).

Probably, but it could also blow in only four hours at 13A.

I'd rather rely on a servant to turn the thing off than a fuse.

[AlexC1981]

Another 3A fuse has blown. I suppose I had better return it to the shop that I bought it from. It must have developed a fault because it was fine for around 30 hours or so use and now it's blown two fuses within 10 minutes of use each time.

[Shaw Tarse]

Just wrap the fuse in tinfoil!

Disclaimer : This might not be a good idea!

[Morningside]

Shaw Tarse said:

Just wrap the fusenail in tinfoil!

Disclaimer : This might not be a good idea!

EFA


600w / 240v = 2.5A

750w / 240v = 3.125A

Edited by Morningside on Monday 28th February 14:07

[cjs]

Morningside said:

EFA


600w / 240v = 2.5A

750w / 240v = 3.125A

Edited by Morningside on Monday 28th February 14:07

We run on 230v in the UK. So 600w-2.6A

[cjs]

AlexC1981 said:

Another 3A fuse has blown. I suppose I had better return it to the shop that I bought it from. It must have developed a fault because it was fine for around 30 hours or so use and now it's blown two fuses within 10 minutes of use each time.

Stick a 5a fuse in and see if that blows, the cable will take it, if that blows then you know there is a fault with the appliance. 3A fuses are a waste of space, in fact they are dangerous as they blow too easily and then require someone to take the plug apart and potentially do something inappropriate. Many appliances automatically come with 13A fuses because of this.

[Mr GrimNasty]

cjs said:

Morningside said:

EFA


600w / 240v = 2.5A

750w / 240v = 3.125A

Edited by Morningside on Monday 28th February 14:07

We run on 230v in the UK. So 600w-2.6A

The supposed range is 216.2 - 253V if you want to be a pedant........

[Deva Link]

cjs said:

We run on 230v in the UK. So 600w-2.6A

Mine varies between 244V and 248V - checked with a couple of good quality meters and it shows the same on the UPS log.

[hairyben]

cjs said:

We run on 230v in the UK. So 600w-2.6A

In theory.... But like the other poster say 255v is not uncommon, which with a 600w/230v (88.5ohm) element will give you 2.9A. Add in the cold element current surge and it's not surprising a 3A would blow, personally I'd try a 5A too unless the heaters specifically marked 3A.

The function of a fused plugtop is to protect the mains lead from the 32A supply fuse, many countries use 10/15A supplies and no plug fuses.

[Morningside]

Deva Link said:

cjs said:

We run on 230v in the UK. So 600w-2.6A

Mine varies between 244V and 248V - checked with a couple of good quality meters and it shows the same on the UPS log.

Funny you say that, I was going to print out the UPS log on here but I cannot remember the password