Discuss sockets wired in 1.0mm 3 core flex in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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electrician4u

Doing a re-wire for a customer who's had their kitchen redone recently and told me the electrics are fine.when I checked, they've all been wired using 1.0mm 3 core flex then sealed underneath tiles.I can't remove the tiles or pull through new cables.Is it permissable to leave it connected like this and if I do, what max breaker can I use?Can I simply write on the form about the departure from the regs?
 

Marvo

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How is the circuit protected? Isit a ring or a radial? Maybe it is safe if they've used a 5A MCB. :)
 
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electrician4u

I did metion they're sockets so I don't think a 5A MCB is a serious suggestion.I also mentioned I cannot rip off the tiles so purchasing a scutch chisel would seem somewhat pointless.Any serious suggestions?
 
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Deleted member 26818

Taking into account that there are probably de-rating factors that would apply, most likely 10A.
If there are no de-rating factors, then 16A.
 

Marvo

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Your questions are somewhat confusing. It doesn't matter that they're sockets, the MCB size is determined by the the CSA of the cable, it's length and the installation method.

My questions are still relevant; is it a radial or ring? How is the circuit protected ie is there an RCD or RCBO?
 

Strima

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Best change the MCB for 10A then if your cable calcs allow. If their kitchen has been done by a company I would be recommending that they get them back to do it properly. As they require power then I would run in a circuit that would be suitable in the mean time IF and a big IF they are willing to go for the extra spend.

Did you do a full survey before the rewire and agree and limitations etc with the customer?
 
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electrician4u

they appear to be wired as a ring which i can connect into and i'm changing the CU so would i get away with a 20 A MCB?
 
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electrician4u

I did a limited PIR before but didn't take every socket off the wall.Had no reason to suspect that it had been done in flex.I assume the homeowner either did it himself or a mate of the kitchen fitter did it. either way, it makes it difficult to remedy.
 

Strima

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Is there an EIC for the sockets? It would be worth looking at.
 
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electrician4u

you're kidding aren't you.?..it's clearly not been done by an electrician
 

Richard Burns

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This is certainly an unusual and poor method of installation, however since the ccc of a 1mm flex is 10A (so long as there are no derating factors (which is unlikely) ) then you would be able to have this as a ring on a 20A MCB.
I would tend towards spin's position and use a 16A MCB to allow for the installation methods. This could lead to nuisance tripping, especially in a kitchen, but would meet the requirements of the regulations ( but I would make a note on the certificate). It may be a good idea to, if possible run in another radial for high current appliances like kettles and toasters so that they are off the main ring.
A standard household circuit should be OK on 16A but maybe not a kitchen.
 
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Deleted member 26818

they appear to be wired as a ring which i can connect into and i'm changing the CU so would i get away with a 20 A MCB?
No.
You have cables with a maximum CCC of 10A, that's without any de-rating factors.
You place a 20A load anywhere other than at the mid point of the ring, and you're going to oveload one of the cables.
The maximum you can have is 16A.
 

kingeri

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Simple answer is that it needs redoing properly. Customer might not like it, but I'd advise them to get hold of whoever did this and either wring their neck or get the money back.
 

Murdoch

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If you know this 1mm core is there and the customer wont agree to remedial work you should simply walk away.

Too much hassle IMHO.
 
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electrician4u

why would a load need to be midway in a ring to avoid overloading??that's the point of a ring, that every point is the same in regards to any load upon it.I find that worrying that someone would think otherwise
 
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electrician4u

I can't walk away from the job.I've already started and ripped most of the (old) cable out.Another example of the customer thinking I'm trying to milk more money out of the job! As far as they're concerned it's a case of it's been working fine since it was put in, so leave it
 

needasparks

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I can't walk away from the job.I've already started and ripped most of the (old) cable out.Another example of the customer thinking I'm trying to milk more money out of the job! As far as they're concerned it's a case of it's been working fine since it was put in, so leave it
Sorry fella but you ARE trying to milk them as this problem should have been spotted and mentioned to them before you started.
people on here are trying to advise your question and it would seem you know better than them as you don't want to accept the replies.
Perhaps they should rewrite the regs for each job you want to do to suit you.
 

snowhead

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Deleted what I wanted to say...

I am speechless....

I'll say it for you,

I can't believe anyone can think leaving the flex in is satisfactory or even complient.
And trying to make a ring out of 1.0mm?
And in a kitchen?

Regardless of what the customer wants or not, it's either a proper job or walk away, even if you've spent money.

This job will come back to haunt you in the future, maybe sooner rather than later.
 

Heisenberg

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I can't believe anyone can think leaving the flex in is satisfactory or even complient.
It is my understanding, and I'm sure that someone will correct me if I'm wrong, is that the fact that flex was used is not the issue here, it's the fact that the CSA is not sufficient.
I had always believed that the reason people use T&E over flex is that flex is much more expensive. As long as the CSA of the cable meets the CCC requirements, surely it does not matter if it is flex or T&E? Am I wrong in thinking this?? Reg No please ?
 
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Geoffsd

That's correct but I'm sure snowhead just meant the flex used here.
 

kingeri

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It is my understanding, and I'm sure that someone will correct me if I'm wrong, is that the fact that flex was used is not the issue here, it's the fact that the CSA is not sufficient.
I had always believed that the reason people use T&E over flex is that flex is much more expensive. As long as the CSA of the cable meets the CCC requirements, surely it does not matter if it is flex or T&E? Am I wrong in thinking this?? Reg No please ?
I believe you're right, flex could be used, so long as the CSA is adequate for the job. Could actually be easier to work with, but as you say would be too expensive!
 

snowhead

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It is my understanding, and I'm sure that someone will correct me if I'm wrong, is that the fact that flex was used is not the issue here, it's the fact that the CSA is not sufficient.
I had always believed that the reason people use T&E over flex is that flex is much more expensive. As long as the CSA of the cable meets the CCC requirements, surely it does not matter if it is flex or T&E? Am I wrong in thinking this?? Reg No please ?
To clarify then: "The flex", as in the 1.0mm flex stated by the O.P.
 

Strima

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Is it me or are there no de-rating factors for flex, or have I gone blind...

Is the stuff not designed to be free in air and only have some minor weight bearing capability for supporting lamp holders etc...

Or am I talking complete bollox...
 

trev

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Is it me or are there no de-rating factors for flex, or have I gone blind...

Is the stuff not designed to be free in air and only have some minor weight bearing capability for supporting lamp holders etc...

Or am I talking complete bollox...
Would it not be prudent to apply some derating though? If something can carry 10 amps but is thenfor example, buried under a mountain of tickly wool it's going to have an effect on it
 
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