Shower Question

[Paul_K]

Hi guys, I'm new here so go easy! :-/

Need some advice on a shower that keeps tripping the breaker!

I have a 9.5kw shower running on 230v supply with a type B 32amp breaker. I've taken a measurement using a clamp (Fluke i410) from the wire at the consumer unit and it's measuring about 36amps and not the 41.3 as the calculation would expect. This problem appears to be too much current?

My question is this:
Can I safely put a higher rated breaker in, say 40amp, using the existing wire? I think it may be 6mm, but not entirely sure.

Much appreciated,

Paul.

 

[Mark.W]

Depends on what size cable is supplying the shower, what the derating factors are etc! Distance of the run!

 

[telectrix]

if the cable is 6mm and clipped direct, then a 40A MCB would be suitable. this assumes that no part of the cable is covered by insulation.

 

[dim_bulb]

Whats the run of cable which method?

 

[Paul_K]

I'd hazard a guess and say between 10-15 meters, as the consumer unit is downstairs, and the shower upstairs! :-/

 

[Paul_K]

I've taken a photo of the consumer unit. Is there any way of posting it up?

 

[Steve_P]

Use the advanced editor or link the URL to photobucket or something. What is the cable size?

 

[vjsmarwick]

my guess is this is a shower upgrade done on the cheap and on 6mm cable protected by 32A breaker and i would hazard a guess you need to upgrade cable to 10mm and breaker to 40A no way would i ever run a 40A on 6mm but that's me.

 

[Geoffsd]

i would hazard a guess you need to upgrade cable to 10mm and breaker to 40A no way would i ever run a 40A on 6mm but that's me.

Why would you hazard a guess?

6mm² clipped direct is rated at 47A and nearly five times the csa of 45A fuse wire.

 

[Paul_K]

Hi all,

To be honest I don't know if it's 'clipped direct' or not, or what the installation method used is!! We've only been in the house just over a year and this has been a recurring issue since moving in with this shower. It normally only trips if you're in it longer than say 10 mins... :-/

Steve, I can't attach links yet as I'm just newly registered on the forum. Apparently I need to post 6 comments first!

 

[polo1]

Where about are you? Someone one here may be able to drop in and offer specific advice, and if appropriate change the breaker. Is the breaker covered by an RCD?

Regards.

 

[Hawk81]

Why would you hazard a guess?

6mm² clipped direct is rated at 47A and nearly five times the csa of 45A fuse wire.

Everyone who comments on this thread is hazarding a guess as the OP has not give the full info needed

 

[Mark.W]

Uhhhhh Hummmm!

 

[Geoffsd]

Everyone who comments on this thread is hazarding a guess as the OP has not give the full info needed

That may be true.

However, the quote also contained "no way would i ever run a 40A on 6mm but that's me".

There seem to have been several posts lately where 'electricians' do not trust the regulations and install cables which are larger than necessary 'just in case'.

If it complies, it complies.

 

[dim_bulb]

perhaps 25mm tails just to be on the safe sideresents1:
did you get a cert when the shower was installed?

 

[Paul_K]

We've only been in the house a little over a year. The shower occasionally trips, and has done since we moved in! We were never given any test documentation when we moved in at all. It was only last night I decided to see what current was going through the cable, and using a Fluke i410 clamp, realised it was around 36amps on a 32amp breaker! This is why I was asking if the cable could take a 40amp breaker without risking a fire..

It appears there's other factors involved that I wasn't too sure about that I can't really give answers to, such as cable length and installation method etc.. It looks like I'll just have to get someone to look at it. :-/

 

[MDJ]

'electricians' do not trust the regulations

To Right, although the vast majority has merit, some of it is made up by men in suits with nothing to do except to look busy so they don't get the boot by the IEE haha, I'm not suggesting this thread has anything to do with my comments, but in general I would think most decent sparks can use the regs and on occasion think about professional standards and not the minimum the regs suggest LMAO.

 

[Geoffsd]

To Right,

Fair enough. Agreed.

I should have said CCC tables. (not regulations)

 

[vjsmarwick]

Geoffsd if your happy doing it your way then leave me to do it my way i did state that is just me but i err on the side of caution not on the side of if it fits use it and i know which i would rather have in my own house thanks !!!!

 

[Geoffsd]

The CCC tables err hugely on the side of caution.

 

[vjsmarwick]

ok so if i install a cable above the insulation and everything is ok and then they come along and top up the fibreglass in the attic space as is common place now and i had used 6mm cable where do the regs stand on this ? if someone else changes the shower for a larger one and does not bother checking anything what does the regs say ? nothing i have my reasons for the things i do i do my own thinking in the original post there was no cable length no fixing method so i gave my honest opinion as i would to anyone i will not make any apologies for trying to make sure i give the best information for safety i think i can give and as stated i did state that its just me!

 

[Geoffsd]

ok so if i install a cable above the insulation and everything is ok and then they come along and top up the fibreglass in the attic space as is common place now and i had used 6mm cable where do the regs stand on this ?

The regs. do not stand anywhere on hypothetical future occurrences.
If you are worried then install the 6mm. up higher.

if someone else changes the shower for a larger one and does not bother checking anything what does the regs say ? nothing

Of course they say nothing.
They do not foresee and allow for idiots in the future.

i have my reasons for the things i do i do my own thinking in the original post there was no cable length no fixing method so i gave my honest opinion as i would to anyone i will not make any apologies for trying to make sure i give the best information for safety i think i can give and as stated i did state that its just me!

All well and good but -

no way would i ever run a 40A on 6mm but that's me.

 

[vjsmarwick]

6mm Twin & Earth Mains Power Cable Flat Grey upto 47A - 10m



Suitable for appliances such as cookers & light showers

Maximum rating at 240V

32A - inner wall enclosed in conduit
35A - through inner wall without conduit
47A - surface mounted.


Geoffsd i am not going to argue with you just please ignore what i have to say instead of picking faults in it if you now check what the original poster of the question has added to the information he first posted you will see what i stated makes perfect sense and what i choose to do does not need to concern you i was not asking for your input to my comment nor do i need it i am very happy with the way i carry out my work and in the 28 years i have been doing it have never had a problem or complaint but thanks anyway for your concern

 

[claydor]

10mm t+e on a 40A mcb covered by a 30mA RCD should do it

 

[Mark.W]

To be safe run it in 300mm armoured and clip it direct!

Come on guys this is basic stuff why do we always tend to stray from what the OP has actually asked!

 

[bryanh]

if i said it was black someone here would say no its white.

 

[telectrix]

not quite, black is now blue, same as red is now brown. :furious3:

 

[Toonlad]

Ohhhh noooo we wouldnt.:joker::santa3:

 

[Mark.W]

Are we not talking about 3 port valves now, in which case it's orange!