Shower tripping RCD 5 mins after use

[snipenose]

Just fitted a Triton T80 easi fit.  Shower works fine when in use. The problem, i.e. tripping the RCD, occurs approx. 5/7minutes after shower unit is.turned off.

Its 8.5kw shower connected with a 6mm cable approx 7mts long, 32A rcd.

My sons friend a qualified electrician checked the shower, cable and RCD and found nothing wrong.

Any ideas or experienced anything like this before

 

[Murdoch]

Just fitted a Triton T80 easi fit.  Shower works fine when in use. The problem, i.e. tripping the RCD, occurs approx. 5/7minutes after shower unit is.turned off.

Its 8.5kw shower connected with a 6mm cable approx 7mts long, 32A rcd.

My sons friend a qualified electrician checked the shower, cable and RCD and found nothing wrong.

Any ideas or experienced anything like this before

is this a new install?

is the rcd shared with other circuits?

Did said electrician who’s visited tell you what tests and results he got?

why do you think it’s the shower causing this?

 

[snipenose]

new unit not new install

not shared

for give my terminology/ignorance, I think hesaid he said shower 27A, cable tested to 500V 

no problem with RCD

I just cant understand why it works fine,but trips after time delay

 

[Murdoch]

Is there an isolation switch between the rcd and the shower ?

 

[snipenose]

no there isn't an isolation switch

 

[Murdoch]

no there isn't an isolation switch

the manufacturers instructions show one. What else does the red protect?

 

[kerching]

no there isn't an isolation switch

Really?

didn't the electrician spot this omission?

so,it looks like it isn't installed in accordance with manufacturers instructions then .

is this the only item on the RCD?

what trip times and ramp test results did the electrician get?

insulation resistance test results?

8.5kw isn't 27A

we need a lot more info

just saying

 

[snipenose]

Thanks for your interest guys. I obviously need more info, the electrician is coming back. 

 

[Murdoch]

Thanks for your interest guys. I obviously need more info, the electrician is coming back. 

you haven’t outlined where the rcd is in all this except it’s not shared ......
 

you say it’s not shared, and it’s 32A - are you 100% sure about this?

do you understand how rcds work ?

i would suggest uploading a photo, but you normally need 10 posts to be able to do this

 

[SPECIAL LOCATION]

From the manufactures installation instructions...

https://www.tritonshowers.co.uk/pub/media/custom/upload/File-1366041415.pdf

read point "6"  on the electrical installation bit... 

6.  A 45 amp double pole isolating switch with a minimum contact gap of 3 mm in both poles must be incorporated in the circuit. 

Which other aspects of the manufactures guidance have been omitted?

If the circuit and cable HAS been correctly installed and tested...

then by default you have a fault on your shower unit..

But if it has been a bit of a bodged install...

Then the possibilities are quite wide ranging.

:coffee

 

[ProDave]

new unit not new install

I just cant understand why it works fine,but trips after time delay

Is that a NEW shower you have just fitted as a replacement to an existing circuit?

It could be a faulty shower where the fault only occurs when it heats up.

The electrician needs to test a bit deeper.  Check the earth insulation of the actual element.  A cold test with no water flowing and the element will not be in circuit.

 

[Doc Hudson]

Just fitted a Triton T80 easi fit.  Shower works fine when in use. The problem, i.e. tripping the RCD, occurs approx. 5/7minutes after shower unit is.turned off.

Its 8.5kw shower connected with a 6mm cable approx 7mts long, 32A rcd.

My sons friend a qualified electrician checked the shower, cable and RCD and found nothing wrong.

Any ideas or experienced anything like this before

So what solution did this qualified electrician suggest as a result of his investigations?

Doc H. 

 

[kerching]

Aha....just spotted this

32A RCD.  So if this rating is correct it is too small as 8.5kw is 37 Amps to start with

is it an RCD or a MCB?

has it got a dedicated test button on it marked 'T' or Test?

Also, if it IS an MCB instead of an RCD it should have an RCD to comynwith Mi

and if it IS an MCB how did he test it...that would be interesting

 

[ProDave]

Aha....just spotted this

32A RCD.  So if this rating is correct it is too small as 8.5kw is 37 Amps to start with

is it an RCD or a MCB?

has it got a dedicated test button on it marked 'T' or Test?

Also, if it IS an MCB instead of an RCD it should have an RCD to comynwith Mi

and if it IS an MCB how did he test it...that would be interesting

He said "is only item on rcd"

So i think you have nailed it, it's a 32A rcbo?

 

[Murdoch]

He said "is only item on rcd"

So i think you have nailed it, it's a 32A rcbo?

I think we can guess all we like but unless the op comes back .........

it’s the tripping 5 - 7 minutes after it’s been used that makes me curious

 

[kerching]

Mr Merlot says 

it's a 32A MCB that is rated too low

it is wedged between two other MCBs that are running warm

it gets hot when showering as it's NOT been installed correctly and inline withnmias

combined heat of the three trips the thermal setting as there is no where for the heat to dissipate

......mérci

 

[SPECIAL LOCATION]

Well as the manufactures instructions suggest a 40Amp MCB is required...

By default any RCD must also be capable of carrying 40A or greater....

Then IMHO the whole hash-up is against the manufactures guidance, And thus.. against BS7671 wiring regulations guidance...

So TBH...  all sorts of strange things could happen...!!

:shakehead

 

[Evans Electric]

Could be a  32 A   /   30mA  RCBO   ,  possibly sandwiched between two other  devices ,,,  the thermal part of the overload   overheats during  showering   , finally trips  even after  shower is finished.        The unit must operate on around 35A  .         

I've known showers work on the old 30A   breakers with a  downstream RCD,      they work because a shower is usually  over in  say 10 mins .        

I have a customer who takes foster children for short periods ......one of them used to run the shower for more than an  hour  ( no idea why)   which melted those two 16A  micro switches  that switch the two elements in .  

 

[kerching]

Could be a  32 A   /   30mA  RCBO   ,  possibly sandwiched between two other  devices ,,,  the thermal part of the overload   overheats during  showering   , finally trips  even after  shower is finished.        The unit must operate on around 35A  . 

Keep up,at the back boy......

M Merlot already hypothesised that theory

 

[Evans Electric]

Ooooops  I missed that post   ...apologies to  Mr Merlot     :C