shower fuse started to blow.

[petem]

I've got a 9.5 kw shower that i put in about 6 years ago that has just decided that it wants to keep blowing its fuse.

I have about 10 -15 metres of 10mm cable(not embedded into walls) from the main fuse to the shower unit and i'm using a 30A fuse.

The fuse went once about 3 yrs ago but no probs till about 6 weeks ago.
I smelled fishy burning bakelite when the shower stopped - mid hair wash - and sure enough the fuse had gone.

Replaced fuse but i have had the same problem again 2 weeks later, and now again today.

Has anybody got any suggestions??

All i can think is the shower is getting old and needs replacing but nothing seems worn inside- no rust or wear on wires- could the heater element be shorting?? How could i test for that?

But something is drawing too much current obviously.

We do have fluctuating water pressure but not to a great degree, if that could be a possible problem, but it has always been like that.

Any help would be greatly appreciated.

 

[macmini]

The fishy smell will be something burning, check the switch connections and connections in the shower itself.

 

[petem]

yes the fuse holder cartridge was melting, that was the fishy smell but what i really would like a bit of help with is what could be the reason for the fuse repeatedly blowing??

 

[ninebob]

what could be the reason for the fuse repeatedly blowing??

I think you've answered your own question here:

I've got a 9.5 kw shower ..... i'm using a 30A fuse.

9.5kw @ 230v = 41.3A.

What type of fusebox/CU do you have, and what rating is the main switch? It may be that you can simply uprate the fuse, but in many older set-ups you must not do this. In any case you must make certain that the cable is 10mm as you say.

 

[petem]

I just rechecked the wire and i got it wrong. The cable to the shower is only 6mm.

As to the fuse box, the house is in major need of a rewire and the fuse box is a stand alone unit connected directly to the meter.(on an old meter board)

I don't think i should uprate the fuse too high, do you think a 35A may be any better?? Don't think i should go any higher.

Also just a little confused as to why, after 6 years, it should start to pull enough current to blow several fuses

 

[petem]

and yes a rewire is in the pipeline

 

[ninebob]

If a rewire is pending, your only option is not use the shower until it's done!

do you think a 35A may be any better?

Without being funny, what makes you think a 35A fuse will be any better for a 41.3A appliance? In any case, your cable is too small.

Fusewire has certain characteristics meaning it can sustain an overcurrent for a varying amount of time. You were "lucky" in the first place that it lasted so long. I'd be more concerned about the under-rated cable, which could potentially overheat causing fire.

Get around to having your rewire done ASAP. In the meantime, have a bath - it's more relaxing anyway!

 

[petem]

thanks for the help!!