Flooring Tripping RCD

[ruston]

@telectrix . It's the best place for it to be lol. I'm an optimist. (Sometimes )

 

[Jamie Harper]

Hi all, sorry for the late reply, i wanted to ignore it over Christmas! But i am back to figure out this issue!
So in response, i did check out of the box and everything was okay.
It appears to be where one of the wires (heating) have been nicked ever so slightly.
Now i can not access the floor, as it has 2 layers of self level, underlay and laminate on top, so no way of fixing the issue directly.

I have, however, had an idea, which I would like an opinion on.
This may be controversial...

Now the issue is only between Live and Earth, as we have established.
So do i actually need to connect the Earth from the mat to the thermostat?
I understand that earth is required for safety/fault conditions, but the whole mat is under self level, with no way of getting to it (unless drilling through the floor).
I know there will be some unhappy people for even considering this, but I can not see any reason to why not connecting the earth to the mat would cause any issues UNLESS i was to drill through into a wire for instance.
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Hopefully it’s nicked in the cold tail between floor and wall so should be a reasonably easy fix

unfortunately not, it was the heating wire that was nicked....

 

[DPG]

You say 'the issue is only between live and earth'. This is the most crucial one unfortunately.

 

[Jamie Harper]

You say 'the issue is only between live and earth'. This is the most crucial one unfortunately.

But i do not connect the earth to the system, the fault does not exsist? what harm can this cause? It is a closed system effectively, the wires are in the floor with no chance of touching them?

 

[DPG]

I know what you meant, but it is not wise to remove the earth on a known faulty circuit. Especially in a bathroom.

Out of interest, why did you bother testing if you were going to ignore the dangerous results anyway?

 

[Jamie Harper]

I know what you meant, but it is not wise to remove the earth on a known faulty circuit. Especially in a bathroom.

Out of interest, why did you bother testing if you were going to ignore the dangerous results anyway?

Its not in a bathroom, its in a kitchen.

It's not that i was always going to ignore dangerous results? My main issue was always ensuring the resistance between L and N were maintained. I never expected this to occur, if i had measured the L & E when i noticed the nick in the cable i would have corrected it, but unfortunately i didnt test it...

Its not a dangerous result either? it if were a direct short i would be more concerned, but this obviously shows a very minor error, hence why i cant see an issue with just not connecting the Earth?
I am well aware it is not 'advised' to do this but before i do anything i would like to know people thoughts on what issues it could cause and why it shouldnt be done?

 

[telectrix]

it is dangerous. diss the earth wire and you could end up with a floor that's "live". look what happened to those 3 horses at epsom or wherever. might be a stimulant for break dancing, but not advised.

 

[DPG]

Apologies, not sure why I assumed bathroom. But the principal is the same.

It's a shame it wasn't measured after the first covering layer went down, but no going back now. Who layed the levelling compound? I would be getting them back rather than leaving a potentially dangerous situation.

 

[Jamie Harper]

Apologies, not sure why I assumed bathroom. But the principal is the same.

It's a shame it wasn't measured after the first covering layer went down, but no going back now. Who layed the levelling compound? I would be getting them back rather than leaving a potentially dangerous situation.

It really is a shame, and unfortunately is was me who did it all. Only myself to blame.

Just out of curiosity, what voltage is supplied to the mat, is it just straight 230V or is it usually stepped down?

Like I say, it is not advised at all and i fully understand that. It's just that i see a very small leakage to ground via the Live, and there is no way anything could be touching the wires, no central heating or cabinates, its all effectively insulated by the self level and laminate flooring. It does make me nervous considering this, but i would like some solid proof that it would cause an issue, as currently i cant see any direct danger?

 

[DPG]

These things happen. We all make mistakes.

What you need to bear in mind now though is that you and your family will probably be walking barefoot on this floor. And you do realise how small a current has to be to cause injury?

 

[Jamie Harper]

Another idea one of my engineering colleges had was to try and' burn off' the fault. Obviously the fault is very minor and not a direct short. If I was to use a form of power supply and connect the Live and Earth of the mat up, it could potentially burn the fault away, but i am a little skeptical of doing this. I have seen this method used in various scenarios, but dont want to completely destroy the floor if there are other methods.
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These things happen. We all make mistakes.

What you need to bear in mind now though is that you and your family will probably be walking barefoot on this floor. And you do realise how small a current has to be to cause injury?

Thats the thing, it doesnt take much at all, especially with high voltages used.
I guess it depends on how insulating the self level and flooring would be?

 

[Midwest]

I came across a L-E fault once, where a lighting circuit cable had been nicked by a nail. Had been left like it for years. The whole wall was at supply voltage. Didn't come to notice, until the client decided to have their bathroom refurbished, and the plumber got a shock off touching the wall and water pipes. Never would of believed a plastered wall could conduct electricity, but saw it for myself, so I wouldn't leave it as is @Jamie Harper.

As posted before here I think, there are companies out there, that boast they can trace the exact location of the damage, and repair it. Think its expensive, but might be a solution for you.

 

[James]

It is unfortunate that there is some damage to the heating cable.

it is absolutely not advisable to just remove the earth connection.

• anyone who was to work on the circuit in question could be in danger due to a LIVE (earth connection)
• the earth cable in the heating tape will be surrounded by ground (levelling compound, concrete etc) it will act like a grid and try to bring that section of floor up to 230v. it will be reduced voltage due to contact with the surrounding ground.
• there will be a constant current flow from live to earth that will increase your electricity bill.
• voltage of your floor will vary depending on many factors outside your control. ground water level, humidity, cracking or other damage to floor or substrate, salinity, spillages etc.
• if the circuit is supplied via an rcd or rcbo, it will cause nuisance tripping anyway as there will be times when there is enough current flow to real earth to trip the device. If it is not rcd protected, then see below.
• 
  
• it is quite feasible that one evening, maybe many years from now when the conditions are just right, your wife, child or grandchild will get up in the night, walk in with bare feet and turn the tap on for a glass of water. By holding the well bonded tap and standing on the faulty floor they make the circuit complete and you have to come down to find them dead on the floor in the morning.

Thankfully,
I am one of the majority of electricians that has never had to explain myself to a coroners court or a family of the deceased. I don't know what would be worse but I hope, ensure by good morels and working practices that I am never in that position.

You say your idea is a bit controversial, I am amazed that you have not been hammered for even suggesting it.

you have your profile hidden so I don't know your electrical skill set,

if you are a professional electrician SHAME ON YOU

if you are a diy guy
Please look at what I have written above, whatever expense and/or inconvenience is incurred, is not important. we all screw up every now and then. its how we deal with it that makes us who we are.

Bottom Line, your options are.

1.. rip the floor up and do it again, this time get it right.
2...cut the cables off where they enter the ground, put a radiator on the wall.
3....SAVE MONEY AT THE EXPENSE OF PEOPLES SAFETY.

 

[electric al]

I know its disappointing to think you've messed up by not testing it before the floor went down .
I can also see that you don't want to take the floor up now it's done.
The question is , can you live without underfloor heating ?
Someone may not live if you have a live earth fault and do what your suggesting .

 

[Midwest]

I was thinking the OP is the home owner, might be wrong.