Electric shower case: short circuits (?) and RCBO

[LonniSet]

Hello,

I have just posted in the Electrician's section one photo and two videos of what I believe to be a dangerous situation of short circuits happening within a shower unit.

You can see (also here attached):
1) Extensive burn marks on the plastic cover;
2) A vast amount of water leaking from the round attachment surrounding the hose, in the lower part of the unit;
3) A vast amount of water being trapped in the shower unit
In another video I hold it is possible to hear loud popping sounds at all times, when the shower is on.

I am not an electrician and I would greatly value feedback from qualified electricians on this matter.

I believe the visual evidence demonstrates that the presence of short circuits and therefore of a dangerous situation.
A qualified electrician, before replacing the unit, also described the situation as extremely dangerous.

However, the RCBO never tripped when popping sounds and internal burn marks were being generated, nor did it trip when the shower was leaking so abundantly.

My landlord denies even the possibility that the one described could be a dangerous situation, because the RCBO feature is in place.
According to them it did not trip because the water, with the cover on, was being contained and directed downwards rather than passing over the wiring. I am not an electrician but I think this is absurd.

My understanding is that the RCBO may not trip for a variety of reasons, making this potentially life-saving safety feature totally useless/invalid.
Am I right?

What do you make out of this visual evidence, and in particular do you agree that it demonstrates short circuits?

The unit has now been replaced.
What sort of inspection should be done in order to guarantee the absolute safety of the system, given it failed to trip under these conditions?

Many thanks for your very much valued opinions.

 

[James]

If it has been replaced, it should have been installed by a professional and you should have a certificate to show it is safe enough to meet requirements.

you should be provided with a minor works certificate.

 

[123]

Those aren't burn marks on the front plastic cover, it's carbon from the motor brushes and normal for a power shower.

 

[nicebutdim]

The water pouring out suggests a burst rupture disc. Can't be certain, but that's certainly what it looks like and would be an easy, cheap fix.

 

[Dartlec]

Electric showers are not particularly well designed, but in general, they are designed so that a water leak around the pipe at the bottom (common if the washer in the hose is old or not connected), won't cause an immediate electrical danger.

If the RCBO is correctly installed and functioning correctly, then it will detect dangerous instances, both of short circuits, and of earth leakage. (They are different things)

If there had been a short circuit, then I would expect any charring/black marks to be around the wiring terminals in the shower and that doesn't seem to be visible in any of the pictures/video.

Water and electricity are always a poor mix, so it is good to be careful about them.

You can check yourself that the RCBO is functioning by pressing the test button on it and ensuring that it trips. This should be done every 6 months in any case.

Since this is a rental, you should have had an EICR at some point in the last year or so - and been provided with a copy. That should show as satisfactory and show that the RCBO in question tripped within the required times.

In terms of outside inspections you could ask that an electrician tests the circuit at the shower end, to ensure that what we call the Zs is sufficiently low. In effect it ensures that the earth is correctly fed to the shower. It would take no more than a few minutes and would prove the circuit as safe.

Clearly the leak is something that a landlord needs to address as it could potentially lead to a dangerous situation. However, I'm not seeing any immediate evidence that the RCBO failed or that a dangerous situation existed.

 

[LonniSet]

If it has been replaced, it should have been installed by a professional and you should have a certificate to show it is safe enough to meet requirements.

you should be provided with a minor works certificate.

Thank you James,
It has been replaced and the professional who installed the new unit did not issue a certificate as far as I am aware.

 

[LonniSet]

Those aren't burn marks on the front plastic cover, it's carbon from the motor brushes and normal for a power shower.

Thank you for your opinion. May I ask you how you would recognise them as being carbon marks rather than burn marks?
The marks have never been commented before, by anyone, and I have always assumed them to show burns/prove of short circuits (as for the popping sounds described before), so I'd be keen to better understand your interpretation.

 

[LonniSet]

Electric showers are not particularly well designed, but in general, they are designed so that a water leak around the pipe at the bottom (common if the washer in the hose is old or not connected), won't cause an immediate electrical danger.

If the RCBO is correctly installed and functioning correctly, then it will detect dangerous instances, both of short circuits, and of earth leakage. (They are different things)

If there had been a short circuit, then I would expect any charring/black marks to be around the wiring terminals in the shower and that doesn't seem to be visible in any of the pictures/video.

Water and electricity are always a poor mix, so it is good to be careful about them.

You can check yourself that the RCBO is functioning by pressing the test button on it and ensuring that it trips. This should be done every 6 months in any case.

Since this is a rental, you should have had an EICR at some point in the last year or so - and been provided with a copy. That should show as satisfactory and show that the RCBO in question tripped within the required times.

In terms of outside inspections you could ask that an electrician tests the circuit at the shower end, to ensure that what we call the Zs is sufficiently low. In effect it ensures that the earth is correctly fed to the shower. It would take no more than a few minutes and would prove the circuit as safe.

Clearly the leak is something that a landlord needs to address as it could potentially lead to a dangerous situation. However, I'm not seeing any immediate evidence that the RCBO failed or that a dangerous situation existed.

Hi Dartlec,
Thank you so much for your assumptions on what the problem might have been.
I have so confused about it, I cannot make sense of it yet.
What confuses me the most is not only the presence of black marks on the cover, or the amount of water leaking, or even the popping sounds I have described - I regret not being able to upload that one video too, but its format it's not accepted here -, but the very fact that two professional electricians, when they faced the situation before it was amended, described it as extremely bad, dangerous and possibly lethal.
As a qualified electrician describes a situation as such, I want to think they are aware of what they are saying and that they have the professional ability to discern.
The contract between their company and the landlord has now been ended as 'poor behavior'. But no one has ever explicitly guaranteed that there was no danger. So it's all incredibly vague and contradictory.

A new ECIR was issued just a while ago, after the unit was replaced.
May I verify the Zs in there and if so, where?
Thanks again,
Lonni

 

[Dartlec]

Hi Dartlec,
Thank you so much for your assumptions on what the problem might have been.
I have so confused about it, I cannot make sense of it yet.
What confuses me the most is not only the presence of black marks on the cover, or the amount of water leaking, or even the popping sounds I have described - I regret not being able to upload that one video too, but its format it's not accepted here -, but the very fact that two professional electricians, when they faced the situation before it was amended, described it as extremely bad, dangerous and possibly lethal.
As a qualified electrician describes a situation as such, I want to think they are aware of what they are saying and that they have the professional ability to discern.
The contract between their company and the landlord has now been ended as 'poor behavior'. But no one has ever explicitly guaranteed that there was no danger. So it's all incredibly vague and contradictory.

A new ECIR was issued just a while ago, after the unit was replaced.
May I verify the Zs in there and if so, where?
Thanks again,
Lonni

On the final real page of the EICR there should be a 'schedule of test results'.

One of the lines should be for the shower circuit, and Zs will be one of the columns with a figure, likely between 0 and 1 (0.45 as an example).

If you can post that schedule page, with no company or identifying information visible, we can tell you whether it looks sensible.

Given that there does appear to be moisture inside the shower, I don't think it would be unreasonable to ask for it to be tested again if you want to be sure.

It does appear that the shower needs fixing one way or another, if it hasn't been already, as any leaking shower can lead to a potentially very dangerous situation if the water ends up where it shouldn't.

 

[brianmoooore]

It's not a 'electric shower' in the normally accepted definition. This is simply a shower mixing valve with a built in pressure boosting pump, and only consumes a fraction of the electrical power that a 'normal' electric shower would, so may not even have a dedicated circuit from the consumer unit.
The marks on the cover are inline with the motor brushes, so I agree that most of the black is carbon dust from the motor brushes.
That said, there should be no water inside the casing, so if there is, it needs immediate attention, and the shower should not be used in the meantime.

 

[LonniSet]

On the final real page of the EICR there should be a 'schedule of test results'.

One of the lines should be for the shower circuit, and Zs will be one of the columns with a figure, likely between 0 and 1 (0.45 as an example).

If you can post that schedule page, with no company or identifying information visible, we can tell you whether it looks sensible.

Given that there does appear to be moisture inside the shower, I don't think it would be unreasonable to ask for it to be tested again if you want to be sure.

It does appear that the shower needs fixing one way or another, if it hasn't been already, as any leaking shower can lead to a potentially very dangerous situation if the water ends up where it shouldn't.

Hi Dartlec,

A recent EICR document was indeed requested after this mess, and issued before the end of the year (in 2021). I've taken a photo (2 in fact) of the section you've mentioned it on screen and I hope it's well readable.

2021 EICR: From what I see the shower description corresponds to the 4th row of the certificate and the column you mentioned would be the second column in section F.

All circuits maximum Zs are marked as N/A.

There are NO observations/limitations in this certificate.

The previous EICR was issued in 2019, instead, contained the following limitations:
NO ELV CABLING TESTED
HEAD FUSE DETERMINATION BY ENQUIRY ONLY
NO BMS CONTROL CABLING TESTED
NO HEATING , HOT WATER, OR AIRHANDLING CONTROL CABLING TESTED
NO LIFT ROOMS OR LIFT CAR ELECTRICS TESTED
NO SERVER OR IT ROOMS TESTED
NO CABLES INSPECTED WHERE INSTALLED OR HIDDEN WITHIN THE FABRIC OF THE BUILDING
ACCESSORIES TESTED WHERE ACCESS GIVEN
NO ACCESSORIES TESTED WHERE HIDDEN BEHIND LARGE FURNITURE OR APPLIANCES
MAXIMUM 20% OF LIGHT FITTINGS TESTED WHERE ACCESS GIVEN
NO INSULATION RESISTANCE TESTING CARRIED OUT ON CIRCUITS WITH SENSITIVE EQUIPMENT
ATTACHED.
CIRCUITS WHERE NOT FOUND WILL BE MARKED AS UNKNOWN AND TEST RESULTS RECORDED
AS A LIMITATION

The older EICR also contained these observations or 'improvements recommended':
1 3.0 Earthing and bonding arrangements 3.8 Provision of earthing and bonding labels at all appropriate locations C3
2 4.0 Consumer unit(s)/Distribution board(s) 4.3 Condition of enclosure(s) in terms of IP rating C3
3 4.0 Consumer unit(s)/Distribution board(s) 4.4 Condition of enclosure(s) in terms of fire rating C3
I don't think these improvements have been applied.

What do you make of these discrepancies (limitations in the older EICR that 'disappear' with no further works) and of the fact that the Zs have not been reported in the 2021 EICR?
I had already noticed these limitations are gone, but I got no explanation.
And I cannot find that value in the 2019 EICR or even the right section for it, unfortunately.

Many thanks,
Lonni

 

[LonniSet]

It's not a 'electric shower' in the normally accepted definition. This is simply a shower mixing valve with a built in pressure boosting pump, and only consumes a fraction of the electrical power that a 'normal' electric shower would, so may not even have a dedicated circuit from the consumer unit.
The marks on the cover are inline with the motor brushes, so I agree that most of the black is carbon dust from the motor brushes.
That said, there should be no water inside the casing, so if there is, it needs immediate attention, and the shower should not be used in the meantime.

Thank you Brian,
Indeed there was plenty of water and I still don't know why the consumer unit did not trip.
I just cannot imagine why with so much water within the unit the shower power (sorry if I called it electric) just carried on producing those sounds, and leaking both internally and externally, without its circuit being cut off.
My guess is that if you have a RCBO in place then it should work, and that if it doesn't then the reason why it did not work has to be invested properly for a place to be considered safe.
There is indeed a dedicated circuit for it (circuit 3) in the consumer unit.

 

[LastManOnline]

Indeed there was plenty of water and I still don't know why the consumer unit did not trip.

The rcbo can be tested to see if it functioning properly.

the shower... just carried on producing those sounds,

Could possible be "arcing".

My guess is that if you have a RCBO in place then it should work, and that if it doesn't then the reason why it did not work has to be invested

For an rcbo to operate as a result of water ,then
L , N and E will usually need to be "sitting" in water and be physically very close to each other.

 

[Dartlec]

Hi Dartlec,

A recent EICR document was indeed requested after this mess, and issued before the end of the year (in 2021). I've taken a photo (2 in fact) of the section you've mentioned it on screen and I hope it's well readable.

2021 EICR: From what I see the shower description corresponds to the 4th row of the certificate and the column you mentioned would be the second column in section F.

All circuits maximum Zs are marked as N/A.

There are NO observations/limitations in this certificate.

The previous EICR was issued in 2019, instead, contained the following limitations:
NO ELV CABLING TESTED
HEAD FUSE DETERMINATION BY ENQUIRY ONLY
NO BMS CONTROL CABLING TESTED
NO HEATING , HOT WATER, OR AIRHANDLING CONTROL CABLING TESTED
NO LIFT ROOMS OR LIFT CAR ELECTRICS TESTED
NO SERVER OR IT ROOMS TESTED
NO CABLES INSPECTED WHERE INSTALLED OR HIDDEN WITHIN THE FABRIC OF THE BUILDING
ACCESSORIES TESTED WHERE ACCESS GIVEN
NO ACCESSORIES TESTED WHERE HIDDEN BEHIND LARGE FURNITURE OR APPLIANCES
MAXIMUM 20% OF LIGHT FITTINGS TESTED WHERE ACCESS GIVEN
NO INSULATION RESISTANCE TESTING CARRIED OUT ON CIRCUITS WITH SENSITIVE EQUIPMENT
ATTACHED.
CIRCUITS WHERE NOT FOUND WILL BE MARKED AS UNKNOWN AND TEST RESULTS RECORDED
AS A LIMITATION

The older EICR also contained these observations or 'improvements recommended':
1 3.0 Earthing and bonding arrangements 3.8 Provision of earthing and bonding labels at all appropriate locations C3
2 4.0 Consumer unit(s)/Distribution board(s) 4.3 Condition of enclosure(s) in terms of IP rating C3
3 4.0 Consumer unit(s)/Distribution board(s) 4.4 Condition of enclosure(s) in terms of fire rating C3
I don't think these improvements have been applied.

What do you make of these discrepancies (limitations in the older EICR that 'disappear' with no further works) and of the fact that the Zs have not been reported in the 2021 EICR?
I had already noticed these limitations are gone, but I got no explanation.
And I cannot find that value in the 2019 EICR or even the right section for it, unfortunately.

Many thanks,
Lonni

Limitations are decided by the inspector for their inspection so will vary between inspections depending on what they consider appropriate. They don't themselves require work to remedy.

To be honest the ones from the first EICR are clearly a generic list as many don't apply - and probably overkill. The second one should have had some - as no inspector will pull walls apart or lift floorboards to check where cables are running. However, it's not a particularly worrisome issue imo.

The N/A for maximum Zs appears to be an form filling error, but the tested Zs is there as 0.43, which seems reasonable, as does the RCD trip test.

The issues with C3 for the consumer unit are related to the fact that it's plastic and that post 2018 new boards had be be metal. However, there was never a requirement to replace old boards as long as they were correctly installed.

Some people would put those down as a C3 because it encourages them to be changed (though a C3 means recommended but NOT required). However, the general guidance is that as long as there are no loose connections and the consumer unit is not directly in an escape route, then no coding is required.

I am not sure on the bonding clamp one, but it may be that the tag that says "safety earth connection, do not remove" wasn't clear, or perhaps the second person was able to tighten a loose connection and therefore didn't consider it worth mentioning.

Generally in matters of judgement, there can be fine lines between a C3 and no code at all - rather in the way that MOT inspectors will vary somewhat, even within fairly clear guidelines.

A C3 code really only means that an improvement can be made, but is quite a lower standard than a C2 code, which means that a dangerous fault could develop if remedial work is not completed.

It's not unusual for an EICR to have many C3s and still be entirely satisfactory for continued usage. However, a single C2 will make the entire installation unsatisfactory.

Although seeing a shower like you had is clearly worrying and some of your concerns are valid - the shower itself clearly needed/needs to be corrected so there is no water leakage, the electrical inspections themselves seem at first glance to show a safe installation.

I hadn't picked up that it is not a full 'electric' shower in common usage of the term but rather one with a powered pump, though of course with still plenty enough current to cause safety concerns should things be dangerous.

In this case though it is entirely possible that although the cables were moist, there was not actually enough connection between them to trip the RCD - that doesn't mean the installation is dangerous, just that water is not as great a conductor as some people think (it's the contaminants in water that generally make it more conductive). 30mA is specified as the safety cut off because it is considered low enough to protect against serious shocks for most people and it really does not take much to trip one in a fault.

If the leak in the shower has been fixed, then from what I've seen I would not really have any other concerns with the electrical installation in terms of safety - and it certainly seems compliant with the current requirements in terms of protection against electric shock.

 

[LonniSet]

Thank you so much for taking the time to write and send your detailed feedback to me, it would have been really helpful having received proper explanations at the time and that was not the case at all.
Is this feedback supposed to stay anonymous or are you willing/able to share the details of your company?
The landlord has planned a periodic testing plus an additional, unscheduled EICR (!), so I would only be pleased to suggest your services, if possible.
I have just one last question: is there anything specific I should ask to be verified before the next EICR is planned?
The shower has been totally replaced by a new one now, but it was a struggle to have anyone coming (it went on for several weeks after it was reported) and no proper clarifications were ever given.. your input was appreciated and precious,
Lonni

 

[Dartlec]

Glad the explanation helped. I'm a firm believer in trying to explain things to clients in understandable ways rather than hiding behind buzzwords.

Also good to hear that the landlord is willing to go a little beyond their requirements to keep you happy. Many wouldn't!

I'm in NW Kent area, so do cover some parts of London but others are a bit too far for me to be honest. If you're within say 45 mins of the Dartford tunnel I'm happy to send you a pm with my details.

Assuming that the shower has been replaced competently, then I don't think there is anything else that needs to be verified before any periodic testing is carried out.

If you have copies of the previous EICRs handy for whoever does it they will thank you - they aren't always passed on by landlords or agencies.