EICR and unnecessary work?

[plugsandsparks]

But that was the point I was trying to make, you won't get anything to earth on a class II item, the RCD will have no effect whatsoever in the scenario's outlined.

A lot of sparks misunderstand what an RCD can and can't do.

An RCD will only trip on an earth fault/imbalance, they do not provide OCP, that is what I was getting at, they are not a 'magic bullet' that some sparks think they are.

Agreed - Tell you what - I believe they do give benefit, albeit, indirectly - so.
This weekend i will rig up an experiment. I will get a 4G extension and plug in 4 DI chargers or PSUs - whatever i can get my hands on. Then i will plug the lot into my garage which has a 30mA RCD and 20A MCB. I will then attack it with a blow lamp until something gives. If the RCD does not trip first i will donate £50 to the Fire Fighters Charity.
Think its a fair test ?

 

[Strima]

Agreed - Tell you what - I believe they do give benefit, albeit, indirectly - so.
This weekend i will rig up an experiment. I will get a 4G extension and plug in 4 DI chargers or PSUs - whatever i can get my hands on. Then i will plug the lot into my garage which has a 30mA RCD and 20A MCB. I will then attack it with a blow lamp until something gives. If the RCD does not trip first i will donate £50 to the Fire Fighters Charity.
Think its a fair test ?

Best video it then.

 

[Guest55]

Respect to anyone who puts his money where his mouth is.
Dont tell fibs on the outcome of your experiment though lol.

 

[somersetsparks]

Realise that but actually, the EICR does put a high degree of faith in the inspector.
Best practice states that it is up to the inspector to determine the approrpiate category. I know BS have tried to make it more steerable with the latest categories but honestly who else is out there trying to make electricity safe.
Happy to be pulled over the coals over it.

You are right, a large degree of faith is put on the inspector, I would always code a circuit supplying downstairs sockets with no rcd as a c2 now, recommend fitment of rcd or rcd socket nearest door. However the electrical installations were pretty safe without them, therefore I usually make recoomendations and observations but I will not insist on fuseboard replacement etc.

IMO bathrooms are pretty safe with good supplementary bonding in place and RCD's are regarded by some as a 'magic bullett' more so, reading on here, by the domestic sector.

You have to remember, houses (especially flats) were commonly wired with no RCD's right up to 2008, and were considered safe, they have not turned in deathtraps overnight!

 

[Grey Master]

I don't see how an RCD will help safety at all with the above mentioned devices, as an RCD will only trip on an imbalance usually L or N to Earth, not between L to N, and most of the above items are class II (no earth), and are likely if/when they go faulty, to be a fault between L to N which an RCD will not detect.

So if that's the case why do they trip when a bulb 'blows'- no earth involvement there.

 

[plugsandsparks]

Best video it then.

Good idea, will leave the lights and radio on so when something trips i can pan around to the CU. Cannot wait, anybody got an extinguisher.LOL.
Oh and will put it on a nice piece of carpet for that added realism.

 

[spark 68]

@ P&S,

I too am not disagreeing with the merits of RCD's, I believe they are potential life savers, in fact if you read my earlier posts on this and other threads, I have never said they should not be fitted where neccessary.
However they are not the be all and end all, nor are they the 'cure all' for all 'electrical ills', although they have their uses.

Since the 17th ed though, they have been pushed on to the domestic sector, a lot of sparks now use them as a 'magic bullet', for instance when the Zs is too high, and instead of either recalculating cable sizes or rectifying either a fault or design issues, just bung an RCD on it and it will fix it mentality, I feel over-reliance and misplaced trust has been placed on these devices. As others have said from the 16th ed and before we did not rely nearly so much on these devices.

Good luck with your experiment.

 

[Guest55]

You are right, a large degree of faith is put on the inspector, I would always code a circuit supplying downstairs sockets with no rcd as a c2 now, recommend fitment of rcd or rcd socket nearest door. However the electrical installations were pretty safe without them, therefore I usually make recoomendations and observations but I will not insist on fuseboard replacement etc.

IMO bathrooms are pretty safe with good supplementary bonding in place and RCD's are regarded by some as a 'magic bullett' more so, reading on here, by the domestic sector.

You have to remember, houses (especially flats) were commonly wired with no RCD's right up to 2008, and were considered safe, they have not turned in deathtraps overnight!

I understand your stance in how you code installations without rcd's and its your choice as the inspector but.......
you need to consider the implications from automatically giving code 2's to rcd free installations.
many , many properties that are otherwise safe will recieve unsatifactory EICR's and will place a large financial burden on those on the recieving end.
just a thought.

 

[somersetsparks]

@ P&S,

I too am not disagreeing with the merits of RCD's, I believe they are potential life savers, in fact if you read my earlier posts on this and other threads, I have never said they should not be fitted where neccessary.
However they are not the be all and end all, nor are they the 'cure all' for all 'electrical ills', although they have their uses.

Since the 17th ed though, they have been pushed on to the domestic sector, a lot of sparks now use them as a 'magic bullet', for instance when the Zs is too high, and instead of either recalculating cable sizes or rectifying either a fault or design issues, just bung an RCD on it and it will fix it mentality, I feel over-reliance and misplaced trust has been placed on these devices. As others have said from the 16th ed and before we did not rely nearly so much on these devices.

Good luck with your experiment.

Wonder how many sparks would L-N loop impedance when wedging a 30ma rcd on an overly long/poor condition circuit, chances are with 1.0/1.0 T+E It may not even trip within the disconnection times on a short circuit!

BIFF- I'm advocating not automatically giving C2's to RCD free installs! I only apply what is in the regs, and even then I only usually reccommend an rcd socket to be fitted by the back door!

 

[plugsandsparks]

Respect to anyone who puts his money where his mouth is.
Dont tell fibs on the outcome of your experiment though lol.

No sweat, I have been banging on about RCDs. Happy to give to fireservice anyway, after all they have to deal with dodgy electrics first

 

[spark 68]

P&S,
If you do decide to carry out your experiment, FFS please wear suitable PPE, a full visor and gloves as a minimum, we don't want you to lose an eye, or get scadded off of exploding molten plastic.

 

[Guest55]

Wonder how many sparks would L-N loop impedance when wedging a 30ma rcd on an overly long/poor condition circuit, chances are with 1.0/1.0 T+E It may not even trip within the disconnection times on a short circuit!

BIFF- I'm advocating not automatically giving C2's to RCD free installs! I only apply what is in the regs, and even then I only usually reccommend an rcd socket to be fitted by the back door!

You implied that you were with the comment
"I would always code a circuit supplying downstairs sockets with no rcd as C2 now"
????
Sorry but that goes against current guidance.
An actual exterior socket without rcd is a code 2 but any other indoor socket without rcd is a code 3.

 

[plugsandsparks]

P&S,
If you do decide to carry out your experiment, FFS please wear suitable PPE, a full visor and gloves as a minimum, we don't want you to lose an eye, or get scadded off of exploding molten plastic.

Good idea ! Wont need to actually hold the blow lamp, but will be holding the camera.
If i dont get called out, will try it Saturday morning.

 

[plugsandsparks]

 

[Guest55]

I hope photo 3 doesnt show emergency services and the charred remains of a spark lol.

 

[somersetsparks]

You implied that you were with the comment
"I would always code a circuit supplying downstairs sockets with no rcd as C2 now"
????
Sorry but that goes against current guidance.
An actual exterior socket without rcd is a code 2 but any other indoor socket without rcd is a code 3.

Well, the guidance book I got says C2 for sockets likely to supply mobile equipment outdoors, c3 for others. If it was a flat without garden or upstairs flat I would c3 for all sockets, if it was a flat with garden would give C2 and reccomend fitting rcd/rcd socket. My company gives the guidance on the coding and this what they put, It was a Code 2 before the EICR but still pass. Now its a fail.

 

[Guest55]

Why complicate the issue with all the talk of upstairs / downstairs flats , garden / no garden ?
Any socket near an opening window can be potentially used for outside with an extension lead.
And if theres a choice of 2 / 3 / 4 sockets near to an exterior door youre in effect condeming the whole ring main to a code 2 defect anyway.

 

[somersetsparks]

Why complicate the issue with all the talk of upstairs / downstairs flats , garden / no garden ?
Any socket near an opening window can be potentially used for outside with an extension lead.
And if theres a choice of 2 / 3 / 4 sockets near to an exterior door youre in effect condeming the whole ring main to a code 2 defect anyway.

Because an upstairs flat with no garden is unlikely to use equipment outside?
Its up to you what you code and I certainly don't disagree with your reasoning!

 

[Guest55]

Fair enough mate , but it does worry me that your company gives you direction on how to code defects instead of letting you , the inspector , make that judgement call on a case by case basis.
If your company benefits from ensuing remedial works then a case for conflict of interests could be made against them , if you see
my point ?

 

[somersetsparks]

Fair enough mate , but it does worry me that your company gives you direction on how to code defects instead of letting you , the inspector , make that judgement call on a case by case basis.
If your company benefits from ensuing remedial works then a case for conflict of interests could be made against them , if you see
my point ?

Umm.. certainly get your point, The advice they give is guidance though and I can, and regularly do, change it. They and especially I do not care about remedial works, I don't want to be doing them! I just test and record what I find, I never put down 'reccomend new board' even for wooden backed rewireables, as I believe most houses are fixable with a few minor repairs, and its not up to me to push for remedial work, only to record what I find

 

[plugsandsparks]

Well, its wasn't spectacular but it did take a while. Have donated anyway as i was intending to either way.
My view is the smokes would have gone off first as it was horrible and i wasn't even in the garage, i was well away. So for clients in North Derbyshire i offer to install up front RCD and linked 240V smoke alarms at cost of materials for three homeowner / residents in my area. Its only a small difference i know but its a difference



[video=youtube_share;lug9DPG3nj4]http://youtu.be/lug9DPG3nj4[/video]

 

[Strima]

1. Cool, I like burning things.

2. I would have done it slightly differently, possibly a plasterboard jig with an outlet, plug in device and a lamp set on a very low heat. It would have taken longer but I think it would have achieved the same result.

3. It does prove a point about RCD's however how would the outcome change with say a standard BS1363 plugtop wired to an old TV?

4. Your garage is too clean!!! :lol:

 

[somersetsparks]

A true gent.... followed through on a promise!
Interesting experiment and fair enough the rcd tripped first!

 

[plugsandsparks]

1. Cool, I like burning things.

2. I would have done it slightly differently, possibly a plasterboard jig with an outlet, plug in device and a lamp set on a very low heat. It would have taken longer but I think it would have achieved the same result.
3. It does prove a point about RCD's however how would the outcome change with say a standard BS1363 plugtop wired to an old TV?

4. Your garage is too clean!!! :lol:

I would have done it differently for sure, i would have got a fume cupboard and extractor as the garage is full of essence of PSUs, really stinks. Just had a shower as its all over me and i wasn't in the garage but in the fresh air, just walking back in was enough, yuk.

I understand there are different scenarios where stuff is plugged into wall sockets direct but from what i have seen, this was a pretty typical scenario i see in homes and offices.

TV - probably the aerial will help with leakage to earth. I meggered the garage floor before i started and it was 20Mohm so was hoping the extension lead would lend a hand. Goes to show probably best to plug in your DI to an extension lead. I am guessing as i dont know how the circuit leaked as the lot is in the wheelie bin and i ain't pulling it apart now. What i was confident about was the 20A MCB would be happy pumping juice into it.

 

[spark 68]

Well done that man (P&S) for the experiment and the donation.

I think your results are inconclusive though, it is a pity you did not analyse what caused the RCD to trip, as this must have been a fault to earth, which technically cannot happen on class II equipment, I suspect it was to do with the 4-way extension.

A better way might have been to mount a normal two way socket in a piece of plaster board.

Well done anyway though, I respect you for giving the donation and having the balls to try.

 

[plugsandsparks]

I put the fire out with water so will have to dry it all out before i can megger it, but looking at it (its just a load of carbonised mess) it looks like carbonised plastic has managed to find a route to earth. No point in pursuing the technical side because for it to trip it has to find a route, i was just predicting that in a typical scenario it would in fact find one quicker than the B20 tripping through short circuit / overload, so from that perspective i still think it scores higher than no RCD even for Di.

 

[plugsandsparks]

Just meggered the remains, extension lead remarkably intact. The PSUs though were tracking to earth through the output cables. After probing the whole lot to make out what was going on i was able to get a 0.21ohm reading between the earth pin of the extension lead and the carbonised remains close to the hotest area. Many areas of the remains showed a reduced insulation property between 3 and 10Mohm depending on how badly it was burned. So i would say the double insulation changed to a double conductor once it got really hot and found a route to the earth inside the extension lead, although the extension lead is intact i would say its gone across the surface via multiple paths.

 

[Stevesplatto]

My understanding of EICRs is they are not to check if an installation is compliant to the latest regs unless, off course, there has been a new addition.
A blanket 'C2' for any installation because it doesn't have an RCD fitted is wrong no matter how desirable RCDs are. The green OSG gives a clear example of a 20 year old installation that's marked down as 'C3' for absence of RCD's to socket outlets used by ordinary persons. we can't just arbitrarily give unsatisfactory reports because an installation could be made safer with the latest equipment..

I find all this a complete PITA. What are we supposed to do, have a complete library of regs to cover any installation we come across? Should we really call installations installed to say 10th edition safe? Most inspections I do there is no previous PIR or accurate record of when alterations/additions were done so how would I know which regs the installation should be compliant to? We just make judgement calls?


I think there should be clear legislation mandating protective devices (BS7671 is non-statutory) requiring at least let properties to be protected by RCDs.


Cheers
s

 

[reefagrim]

Rcd are the best thing ever since the voltage trip they do ajob that they are required to do however . working on the inbalance between earth and or L/N they are designed to allow the uncompetent victim a degree of survival by allowing no more than 0.3 of a amp which should cause sight discomfort and or possibile in difficulty in breathing 0.5 of a amp will be sufficient to stop the heart.
If the guidelines set by the regs recommends a rcd should be fitted and the inspector therefore recommends that a rcd should be fitted then the client should actually listen and beaware that it has a reason to be fitted that is not attached to money. but remembering that at the ccu there are also fitted cb which also work and rcbo are both combined then it can be assumed that these devices will work as they should

it should be remembered that in the world of competent electricians that the incompetent ( the public) will do/try/succeed in making a electrical installation dangerous when they use or do DIY
a friend of mine wanted a socket installed high level above the bath so he could mount a tv when i explained everything why he couldnt he said what about a classII type afetr a lot of swearing he saw my point now he uses a portable and a extention lead .....head in my hands slowly shaking
my point is as long as the electrician or inspector does or writes everything to cover the laws of building control and the recommendations or the regs bs7671 then we can be safety leave the installation happily

 

[Guitarist]

Rcd are the best thing ever since the voltage trip they do ajob that they are required to do however . working on the inbalance between earth and or L/N they are designed to allow the uncompetent victim a degree of survival by allowing no more than 0.3 of a amp which should cause sight discomfort and or possibile in difficulty in breathing 0.5 of a amp will be sufficient to stop the heart.
I

Think you mean 0.03 of an amp.

Unless you are talking about a 300mA RCD of course, in which case I retract my statement....