triton electric shower kaput?

[ricicle]

Even a 10.5kW shower unit wouldn't need a circuit upgrade

Have I missed something

 

[Softus]

Pretty sure I have 10mm cable - it looks beefy...

 

[ricicle]

Pretty sure I have 10mm cable - it looks beefy...

Blimey, I read that three times and still didn't see that-I must be tired

 

[Softus]

Ne'er mind ricicle - it'll soon be September and then you can sleep...

 

[ricicle]

Ne'er mind ricicle - it'll soon be September and then you can sleep...

I won't be allowed to sleep until at least October........

 

[mega_kas]

thanks all.

I will stick with the slightly overloaded 32a MCB, 6mm cable and 8.5kw shower. After all - this house has had an 8kw shower with the same circuit for a couple of years so it should be OK.

If it does trip the MCB then I will do some redisgn and update of the circuit.

 

[Softus]

I will stick with the slightly overloaded 32a MCB, 6mm cable and 8.5kw shower.

After all that are you saying that you don't have 10mm² cable?

After all - this house has had an 8kw shower with the same circuit for a couple of years so it should be OK.

This is not a competent premise - engage an electrician now.

If it does trip the MCB then I will do some redisgn and update of the circuit.

And if the house catches fire, how much redesign will you do then?

 

[Steve]

I will stick with the slightly overloaded 32a MCB, 6mm cable and 8.5kw shower.

After all that are you saying that you don't have 10mm² cable?

Softus, the OP said this a while back. Read the one with the pictures, or just before.

And why would the house catch fire? the cable is protected.

 

[mega_kas]

Softus - so if I had a 7.5kw shower my house would be Ok but if I use a 8.5kw shower my house will definately catch on fire?

If you can take a minute to read the thread you'll see that I recognised that my set up isn't ideal but as crafty says - if the shower draws too much current it will trip the circuit breaker.

I'm pretty sure that this will prevent the house burning down but then I'm not an electrician and don't have a post cout in the 10,0000s

 

[Steve]

mega_kas - just ignore Softus he can be a bit brutal sometimes. Especially when he doesn't have all the info or just cant be bothered to read it.

 

[ricicle]

Uh - oh.....................................................

 

[Softus]

Crafty, I did indeed make the same mistake as ricicle and miss the information about the 6mm² cable, however, this:

Yes. 6mm is rated at 47 amps optimum, but I cant advocate such a gamble when you dont know the route of the cable. If you're comfortable with it, then do it.

...is outrageous. I would say if he's comfortable with not knowing the derated capacity of the cable then the tools should be torn from his unqualified fingers. Here's another appalling example:

I will stick with the slightly overloaded 32a MCB...

_____________

Now then mega_kas...

Softus - so if I had a 7.5kw shower my house would be Ok but if I use a 8.5kw shower my house will definately catch on fire?

Are you being deliberately obtuse? The risk to the cable is determined by its ability to cool itself, which is determined by what it comes into contact with and what insulation might be around it. If you don't know what surrounds the cable, then you don't what the risk is. If you don't know what the risk is, then you shouldn't be doing it. If you do it anyway, without knowing what the risk is, then don't be surprised if you wake up in hospital to be told that your family is in the morgue.

If you can take a minute to read the thread you'll see that I recognised that my set up isn't ideal but as crafty says - if the shower draws too much current it will trip the circuit breaker.

This is another indication that you don't understand then whether or not the breaker is correctly sized is [largely] independent of determining whether or not the cable is correctly sized.

I'm pretty sure that this will prevent the house burning down

You're not at all sure - you're just hoping for the best without understanding, and you're clinging onto some poor advice from someone who agrees with you.

...but then I'm not an electrician and don't have a post cout in the 10,0000s

WTF does post count have to do with being right or wrong, and safe or dangerous?

 

[tim west]

Don't confuse rapid fault tripping with overload tripping remember a breaker can take 1.5 times it's rating for up to four hours before it trips this may be enough for an overloaded cable to be dangerously overheated.(in case of the shower time it will be on probably saves this happening but in other cases it could be significant)

 

[Softus]

mega_kas - just ignore Softus he can be a bit brutal sometimes. Especially when he doesn't have all the info or just cant be bothered to read it.

Watch it Crafty - I have no problem with being criticised when it's justified, and as a case in point my apology for lack of reading has crossed with your jibe, but be very careful when you're advising people who don't understand how to determine cable current carrying capacities.

 

[mega_kas]

softus - you certainly have a way of making your point.

I don't want me or my family in a morgue because of a fire.
I've done a bit of reading about dangerous overcurrent faults and cable selection (section 1.4 and 1.5):

http://www.kevinboone.com/cableselection_web.html


I have 32a MCB and 6mm cable. MCBs are designed to trip overcurrent of 1.45 times nominal current after 1 hour.
therfore the MCB will trip at 32a*1.45=46.4a after 1 hour

So an 8500W shower will draw 35.41a current.

So the question now is - will my 6mm cable stand 46.4amps for 1 hour without overheating?

If no then I will install a lower power shower or uprate the circuit. (with P regs) Probably the earlier as uprating the cable would mean removing tiles and rerouting it up the wall.