fitting RCBO on 9.5kW pumped triton shower

cluelez

Can a qualified electrician advise what size of RCBO would be suitable to include in the set-up:

9.5kW triton t90z pumped shower (new model)
10sq earthed cable (13meters lenght)
45amp pull cord switch
RCBO: ?

I was told in this thread http://www.boards.ie/vbulletin/showthread.php?t=2056995499

that I can't use 40amp RCBO as it's for the 8.5kW pumped shower.
citation: ''40 amp RCBO is for an 8.5kw shower not a 9.5kw one.''

indie armada

You could ring earthridge on 016286711 and ask them what they recomend for their showers.
i would have thought a 40amp rcbo would suffice though.

seaniefr

You were also advised in that thread to get a qualified electrician who should also be an ECSSA or RECI member. Maybe in this case you should leave this one to the professionals.

cluelez

indie armada wrote: »

You could ring earthridge on 016286711 and ask them what they recomend for their showers.
i would have thought a 40amp rcbo would suffice though.

I have send them e-mail (no response so far), so this question is still open for answer.

indie armada

according to their instruction manual that comes with the shower, a 40 or 45 amp rated protection device should be used on a 9.5kw unit.

SpaceTime

Seems to be cutting it very fine at 230V where 9500W would be 41.3 Amps or 43.18 Amps at 220V.

If you were calculating it for 240V it would come in just shy of 40A but not much.

To me, it sounds like it's the wrong spec, but I'd leave it up to the experts.

45A RCBO would sound more like it to me in Ireland anyway which is supplying power at 220-230V not 240-250V. A lot of UK calculations seem to assume 240V.

More importantly, you'd want to make sure that the wiring is capable of carrying at least a 45amp resistive load. Over long runs, that would need to be derated too so, really with this kind of thing you'd want a very competent electrician and not chance you arm.

With a 45A load, you can easily cause a fire and with a shower, anything off about the RCD and earthing arrangement can put your life at risk.

indie armada

i just had a quick look at my garo book and their rcbo's only rate up to 40amps. could the op use a 63amp rcd combined with a 50amp mcb.

2011

cluelez wrote: »

Can a qualified electrician advise what size of RCBO would be suitable to include in the set-up:

9.5kW triton t90z pumped shower (new model)
10sq earthed cable (13meters lenght)

A 10 sq. T & E is generally suitable to supply a load this size for 13m.
However as normal you need to check that the mains supply to the distribution board is suitable, as well as total volt drop (no more than 5% of nominal voltage), earth fault loop impedance etc.

45amp pull cord switch

grand. I would prefer a cooker type switch and always use MK.

RCBO: ?

I have used a 40A (B type) RCBO before on a 9.5 kW triton shower without any issues. If you look at the fusing characteristics you will see why.

As others have said this work should only be carried out by a qualified electrician registered with ECSSA or RECI.

Judging by your questions I would be concerned that you do not have the test equipment or competency required to tackle such a job.

Traditionally water and electricity are a dangerous mixture :eek:

2011

In fact a 32A B type RCBO may well be sufficient.
Form memory I think I did this in my last house and it worked perfectly.

See page 18 of this ABB document:

http://www.systemcontrols.co.in/datasheet/ABB%20Miniature%20Circuit%20Breakers.pdf

cluelez

2011 wrote: »

In fact a 32A B type RCBO may well be sufficient.
Form memory I think I did this in my last house and it worked perfectly.

See page 18 of this ABB document:

http://www.systemcontrols.co.in/datasheet/ABB%20Miniature%20Circuit%20Breakers.pdf

in this thread (post 18): http://www.boards.ie/vbulletin/showthread.php?t=2056995499&page=2

user advised that my set-up is incorrect and may kill someone

frankmul

2011 wrote: »

In fact a 32A B type RCBO may well be sufficient.
Form memory I think I did this in my last house and it worked perfectly.

See page 18 of this ABB document:

http://www.systemcontrols.co.in/datasheet/ABB%20Miniature%20Circuit%20Breakers.pdf

Would a 32 amp not be cutting it fine, if you take too long of a shower then, it might trip on time delay. Some times in our house there might be a few showers been done one after another.

cluelez

frankmul wrote: »

Would a 32 amp not be cutting it fine, if you take too long of a shower then, it might trip on time delay. Some times in our house there might be a few showers been done one after another.

i'm not concerned with tripping.

I'm only concerned with safety.

2011

cluelez wrote: »

in this thread (post 18): http://www.boards.ie/vbulletin/showthread.php?t=2056995499&page=2

user advised that my set-up is incorrect and may kill someone

I know, it matches my advice in post#8

cluelez

2011 wrote: »

I know, it matches my advice in post#8

maybe it's a dumb question.

What was the advice in the post #8 or why me set-up is incorrect?

at present time I have installed 40amp RCBO (there seem to be suggestion in this thread: http://www.boards.ie/vbulletin/showthread.php?t=2056995499&page=2 that this is incorrect).

I wonder what is the correct RCBO for such set-up.

Or do you mean that the load has to be measured (the measure voltage and the vold drop)?

I have the multi-meter, would this suffice?

2011

frankmul wrote: »

Would a 32 amp not be cutting it fine, if you take too long of a shower then, it might trip on time delay. Some times in our house there might be a few showers been done one after another.

Agreed, it would be cutting it fine.

If a 9.5 kW load was connected to a 32 type B MCB then the current drawn would be about 1.3 times the rtaed current of the protective device. Judging by the graph (which is an approximation) it could take anything from about 15 to 40 minutes to operate. In my last house I had a 32A RCBO installed on an 8.5 kW shower. The shower itself died, so I replaced it with a 9.5 kW unit. I decided to replace the RCBO if it tripped. In never tripped so it stayed there.

A 40A B type RCBO would be what I would selcet for a 9.5 kW shower. As can be seen from the graph it would not trip after an hour of continious use.

cluelez

2011 wrote: »

Agreed, it would be cutting it fine.

If a 9.5 kW load was connected to a 32 type B MCB then the current drawn would be about 1.3 times the rtaed current of the protective device. Judging by the graph (which is an approximation) it could take anything from about 15 to 40 minutes to operate. In my last house I had a 32A RCBO installed on an 8.5 kW shower. The shower itself died, so I replaced it with a 9.5 kW unit. I decided to replace the RCBO if it tripped. In never tripped so it stayed there.

A 40A B type RCBO would be what I would selcet for a 9.5 kW shower. As can be seen from the graph it would not trip after an hour of continious use.

Okay, I do agree on the tripping element. Mine does not trip (40amp RCBO + 9.5kW Triton pumped shower)

However, I'm worried about the safety hazard as someone suggested in the thread (that 40amp RCBO isn't correct for 9.5kW pumped triton showers): http://www.boards.ie/vbulletin/showpost.php?p=85591205&postcount=18

2011

cluelez wrote: »

.
What was the advice in the post #8 or why me set-up is incorrect?

This is the advice that I feel you should pay most attention to in post#8:

As others have said this work should only be carried out by a qualified electrician registered with ECSSA or RECI.

Judging by your questions I would be concerned that you do not have the test equipment or competency required to tackle such a job.

Traditionally water and electricity are a dangerous mixture

Or do you mean that the load has to be measured (the measure voltage and the vold drop)?

I mean that you need to look at the big picture.

For a start perhaps you should read this:

http://www.dcenr.gov.ie/Press+Releases/2013/Minister+Rabbitte+moves+to+increase+electrical+safety+in+the+home.htm

I have the multi-meter, would this suffice?

No.
Apart from the fact that this is not a certified test instrument it will not test correct operation of the RCD / RCBO (for example).

2011

cluelez wrote: »

Okay, I do agree on the tripping element. Mine does not trip (40amp RCBO + 9.5kW Triton pumped shower)

However, I'm worried about the safety hazard as someone suggested in the thread (that 40amp RCBO isn't correct for 9.5kW pumped triton showers): http://www.boards.ie/vbulletin/showpost.php?p=85591205&postcount=18

No offence intended but the biggest safety hazzard is you.

You do not have the training required to carry out modifications to a mains voltage distribution board. Even if you did, you do not have the required test equipment or any idea how to use it if you did.

If someone were to be injured or worse as result of your actions you would face criminal prosecution. An insurance company may also use this as an excuse not to pay out if for example the distribution board that you carried out a modification on were to go on fire.

cluelez

2011 wrote: »

This is the advice that I feel you should pay most attention to in post#8:






I mean that you need to look at the big picture.

For a start perhaps you should read this:

http://www.dcenr.gov.ie/Press+Releases/2013/Minister+Rabbitte+moves+to+increase+electrical+safety+in+the+home.htm



No.
Apart from the fact that this is not a certified test instrument it will not test correct operation of the RCD / RCBO (for example).

thanks.

I'm still wondering what type of RCBO is required for my set-up.

2011

cluelez wrote: »

thanks.

I'm still wondering what type of RCBO is required for my set-up.

One fitted by a qualified electrician.

cluelez

2011 wrote: »

One fitted by a qualified electrician.

Hi All,

Thank you for waking me up on this subject.

I have had called qualified electrician and he have completed the following:

1) check the tightness of the connections
2) performed the various tests with the test equipment
3) replaced Blue (negative) cable between RCBO and the board (about 12 cm. from 6sq to 10sq)
4) advised on the periodical tests of RCBO
5) advised about the test: 33amp at full power of the shower for 10seconds.
6) polarity and earthing verified
7) Resistance of the protective conductor .4 OHM
8) Trip Time .29ms
9) Fault Look Impedance 0.5 OHM


After all that carried out I have received Declaration of Compliance ET101.

cluelez

indie armada wrote: »

You could ring earthridge on 016286711 and ask them what they recomend for their showers.
i would have thought a 40amp rcbo would suffice though.

Earthridge responded:

the best would be 45amp

I don't know if this is correct or not but this was their written response.
the fitting manuals state 40/45amp mcb for 9,5kW Triton T90.

I'm not going to dig it deeper - perhaps combination of 45 amp mcb with other protective device may suit current regulations.

At present time my setup with 40amp RCBO passed the test.

mikehammer67

the rating of protective device should exceed shower rating

cluelez

mikehammer67 wrote: »

the rating of protective device should exceed shower rating

this is the correct statement.

When the test was performed the load showed 33amp's between the shower and the board.

Would this means that the protective device at 40amp is suitable for this setup?

Tow

Umm Hello, as they say on the south side of Dublin, there is more to selecting a RCBO than if its Rated Current value should be 32, 40 or 45 Amp. It's Rated Residual Current value is far more important to the person in the shower...

According to IEC 60479, two key levels of electric current need to be considered with
regard to shock protection.
The first is the “let-go” level, which is generally accepted to be around 7mA. At or above
this level, muscles may seize, and a person touching or holding a live part may not be
able to let go of the live part. RCDs rated up to 10mA are intended for protection against
“let-go” currents, and are recommended for use in hospitals and old peoples’ homes,
moist or damp environments, or similar locations.
The second is the “fibrillation” level, which is generally accepted to be around 50mA. At
or above this level, heart fibrillation is likely to occur. RCDs rated up to 30mA are the
upper limit for RCDs intended to provide protection against fibrillation. It follows that
RCDs rated >30mA are not suitable for personal protection.

mikehammer67

Tow wrote: »

Umm Hello, as they say on the south side of Dublin, there is more to selecting a RCBO than if its Rated Current value should be 32, 40 or 45 Amp. It's Rated Residual Current value is far more important to the person in the shower...

irrelevant

it'll be 30mA unless you specify something else

frankmul

cluelez wrote: »

this is the correct statement.

When the test was performed the load showed 33amp's between the shower and the board.

Would this means that the protective device at 40amp is suitable for this setup?

What value is the voltage at when you have the shower running. I'm calculating a figure of around 180 volts

Tow

mikehammer67 wrote: »

irrelevant

it'll be 30mA unless you specify something else

You better hope that no one walks into the likes of a B&Q and takes one off the shelf then.

mikehammer67

Tow wrote: »

You better hope that no one walks into the likes of a B&Q and takes one off the shelf then.

B&Q will only stock 30mA

DIY only uses 30mA

mikehammer67

frankmul wrote: »

What value is the voltage at when you have the shower running. I'm calculating a figure of around 180 volts

180v?

maximum allowable is 4%

i would just size protective device>9500/230 myself

rather than measuring full load voltage at appliance

2011

cluelez wrote: »

Earthridge responded:

the best would be 45amp

I would be interested to know why they think a 40A would not be suitable. I have never used a 45A RCBO and I have conneceted plently of 9.5 kW showers without any issues. A load of less than 42A can be fed from a 40A RCBO all day long without it tripping.

At present time my setup with 40amp RCBO passed the test.

Yup, that is what I would expect, 40A B type (IΔn 30mA)