Am I being a snob, or is this actually dangerous

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Am I being a snob, or is this actually dangerous

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Inteificio

On a distribution board last week in a farm house, I saw 2 core 4mm SWA with the sheath terminated by having a couple of strands in a terminal block.

A photo would save a thousand words, but I found out on that day that my camera phone is not waterproof =-(

The other sparky on site said it is fine if the Zs is in, which I accepted at the time.

Then I got thinking, the Zs will make sure the fuse trips, but how can you guarantee conductor safety while the fuse is tripping?
We had a similar issue in our factory where a spark proved that a distribution circuit would blow in 4s, within the limit. However I pointed out the wires would be melting the insulation after 1s.

I can do the calcs to prove how hot that conductor will get, but that is not sparky level maths and I know the guy who installed it won't be able to do that.

So my question is:

When is it ever safe to terminate only a couple of strands of the armouring on SWA when it is being used as the CPC.

This is quite important as I am going to be politely confronting the guy, and I don't want to risk causing offence if I am wrong. I will be the first to admit domestic is not my speciality.
 
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OK am back =-)

Seems like I missed a long argument.

As ever, people skim on the internet and opinions get miss-understood.

So to clarify.

I do not classify this as safe and if was doing a PIR it would get a cat 1 fail from me. (if we got a PFC there is a small chance of a fire, not sure how small, so therefore it is cat 1).

The reason for the thread was to see if I overlooked anything and to find out if the sparky had any leg to stand on.
Seems pretty clear he does not!

As for deviating from 7671, I meant in general, not this specific example. I do not think this was safe (especially as someone pointed out the obvious I overlooked, there is no mechanical support, good chance that metal fatigue is going to reduce the eCSA over time).

This breaches the building regs, so is statutory, so he is fkd if I report him.



I now have the information I needed to reprimand this person, so that you all for your assistance.


Sorry to say, I will not be able to speak to him for a few weeks (let us hope no fire in the mean time). I will get photos and details as they become available.
 
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I can do the calcs to prove how hot that conductor will get, but that is not sparky level maths and I know the guy who installed it won't be able to do that.




If it is saying what I suspect, then that is presumptuous and a little annoying

Please clarify the above quote
 
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Not sure if I am missing something here. But the only way the wired armour should be used a a cpc is A) if its csa is compliant and B) its correctly terminated with banjo and gland pack. Seems simple enough to me ?? The PFC with regards to earth fault may become a safer bet if an RCD of 30 100 or even 500 ma has been fitted.
But although a hypothetical step in the right direction from a safety point of view.
The way that armour has been terminated is just plain wrong, and needs to be done properly. End of.
 
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In his defence on that one he is not finished, just made things 'safe' over Christmas, so we could use the extension.
Most of the circuits had pencil scribbled on them, so he probably knows what they mean.

Just want to see this job finished, so I can go and fix it!

Part of me wishes I wasn't so busy, so I could have done this job. Then the other part of me realises I am sodding glad I am so busy =-)


For more funny stuff on this spark, when working with him for a day (I volunteered as my domestic experience is limited)

He once climbed up a live factory bus bar (got two rungs in before hearing the life saving "FREEZE" from across the factory, thankfully he listened).
He also asked me to explain how to calculate the current on a lighting transformer!
 
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I am also not sure on what it is protected by. There is confusion on one of the two row boards. The main incomer feeds an RCD protecting the bottom row, but seems to be no RCD on the top.

I am under the impression that as on TT everything, without exception, needs to be RCD, I am really not sure on that though, so if someone can confirm that would be appreciated.

So this is either protected by a 30ma RCD or B MCB on TT.
 
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Inteificio said:
In his defence on that one he is not finished, just made things 'safe' over Christmas, so we could use the extension.
Most of the circuits had pencil scribbled on them, so he probably knows what they mean.

Just want to see this job finished, so I can go and fix it!

Part of me wishes I wasn't so busy, so I could have done this job. Then the other part of me realises I am sodding glad I am so busy =-)


For more funny stuff on this spark, when working with him for a day (I volunteered as my domestic experience is limited)

He once climbed up a live factory bus bar (got two rungs in before hearing the life saving "FREEZE" from across the factory, thankfully he listened).
He also asked me to explain how to calculate the current on a lighting transformer!
Click to expand...
not finished????....sounds to me like he shouldn`t have even started..lolffs.....
 
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For more funny stuff on this spark, when working with him for a day (I volunteered as my domestic experience is limited)

He once climbed up a live factory bus bar (got two rungs in before hearing the life saving "FREEZE" from across the factory, thankfully he listened).
He also asked me to explain how to calculate the current on a lighting transformer!
Click to expand...

Just out of curiosity,how come he ended up on the job of wiring your parents house?
 
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Des 56 said:
If you please,a reply would be considerate of you
Click to expand...

I am saying the mathematics required to precisely calculate the increase of temperature for those two strands is not covered under any electrical course that I am aware of.
do not take this as a slight on electricians, I just meant it is not covered in any of the electrical courses I have taken.
Does not mean that any individual sparky cannot work this out!

The only individual sparky I was referring to was the protagonist of our tale.
If he cannot calculate the current usage of a lighting transformer, it seems a safe assumption that he could not do this far more complicated process.

Was that what you were asking?
 
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basically, if this so called electrician was working on any of my families houses i personally wouldnt allow him to enter back on site, he is a total cow boy and should have the book thrown at him
 
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GLENNSPARK said:
would be interesting as to how he managed to blag his way into the job in the first place..lol....
Click to expand...

I have no idea what he has done, or what still needs doing, so if I threw him off now I would not know where to start.

When he has finished the board will be labelled and the test certs will be there (or I will take his head).
 
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Inteificio said:
I am saying the mathematics required to precisely calculate the increase of temperature for those two strands is not covered under any electrical course that I am aware of.
do not take this as a slight on electricians, I just meant it is not covered in any of the electrical courses I have taken.
Does not mean that any individual sparky cannot work this out!

The only individual sparky I was referring to was the protagonist of our tale.
If he cannot calculate the current usage of a lighting transformer, it seems a safe assumption that he could not do this far more complicated process.

Was that what you were asking?
Click to expand...

Thanks for your response,it seems we do,as electricians, take these factors into account
eg Thermal overload

Thermal overload protection calculates the temperature of the conductor based on specific conductor data and the current present in the circuit,
and is used to protect conductors from damage due to extended overloads.
 
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Inteificio said:
I am also not sure on what it is protected by. There is confusion on one of the two row boards. The main incomer feeds an RCD protecting the bottom row, but seems to be no RCD on the top.

I am under the impression that as on TT everything, without exception, needs to be RCD, I am really not sure on that though, so if someone can confirm that would be appreciated.

So this is either protected by a 30ma RCD or B MCB on TT.
Click to expand...


Seems that your getting a front end RCD protected CU, which ain't the most sensible thing to do on a TT system. Fine if it's an S type 100mA and the rest of the CU is made up of 30mA RCBO's, but somehow with this particular sparks, that is just going to be ''Wishful Thinking''!! lol!! Remember, your parents will be relying on any RCD protection afforded to this installation for earth fault protection, as it's extremely unlikely that your TT system will be up to the job!!!

What i can't make out, you keep talking about waiting till he's finished?? Surely that means destroying other trades finished work?? Then you even say that you will go in and fix this and that!!!! I can see No point whatsoever in waiting until it's finished, ....get these and any other snags that you have found sorted now, with the minimum disturbance to finishes etc...
 
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Engineer54 said:
Seems that your getting a front end RCD protected CU, which ain't the most sensible thing to do on a TT system. Fine if it's an S type 100mA and the rest of the CU is made up of 30mA RCBO's, but somehow with this particular sparks, that is just going to be ''Wishful Thinking''!! lol!! Remember, your parents will be relying on any RCD protection afforded to this installation for earth fault protection, as it's extremely unlikely that your TT system will be up to the job!!!

What i can't make out, you keep talking about waiting till he's finished?? Surely that means destroying other trades finished work?? Then you even say that you will go in and fix this and that!!!! I can see No point whatsoever in waiting until it's finished, ....get these and any other snags that you have found sorted now, with the minimum disturbance to finishes etc...
Click to expand...
aye and get this turnip head out the door n all....
 
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Tell the guy where to go and why.
Then sort it out. If thats the way you want to go, then go that way.
In the time it takes to enter multiple replies to this thread. You can have the job sorted.
And your calcs will hold true within the practicalities of the installation, helping you to sleep content at night.
 
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I’m sorry Inteificio but this thread has got totally out of hand.
Three days and you haven’t done anything to rectify what is obviously a dangerous situation. What have you done exactly? Other than spend time on the net.
 
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Tony said:
I’m sorry Inteificio but this thread has got totally out of hand.
Three days and you haven’t done anything to rectify what is obviously a dangerous situation. What have you done exactly? Other than spend time on the net.
Click to expand...

Gone mountain biking.

I can't get back there for weeks, so have given a long explanation to dad to make sure the dangerous point get fixed asap.
 
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Des 56 said:
Thanks for your response,it seems we do,as electricians, take these factors into account
eg Thermal overload

Thermal overload protection calculates the temperature of the conductor based on specific conductor data and the current present in the circuit,
and is used to protect conductors from damage due to extended overloads.
Click to expand...

I was under the impression the formula in the red book only cover continuous conductor size, the effective conductor size drops for a few cm at the point where only two wires are part of the circuit.
The calcs of this two cm section of wire are more difficult. Not horrendously more difficult, but I would put money on the fact that if I set this problem to my team not everyone would be able to do it.
 
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Here's 3 regs you can throw at him:- 522.8.5, 526.1 & 526.6 or just tell him to read section 526 lol. I'm not going to get into the debate about regs being none statutory but these are the regs that would be used to prosecute in a court of law.
 
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