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Hello,

I've recently had some outside lights fitted, there is about 10 of them, all LED. The electricans took the cable from the fuse board down into my basement void where other services are running and then out to the garden. Outside they have used armoured cable, 1.5mm, about 20-30meters in total I'd have thought. But in the basement void, it's about another 20m from the fuseboard end to the outside but they have used a 0.75mm 3 core white flex cable.

The circuit breaker is 6 amps.

I don't know whether that is good or bad but to me something isn't quite sitting right having a cable half the size of the armoured cable, it looks like they've used a cable very similar to the flex hanging down on my pendants for 20m.

Should I be concerned or is it ok? Since I have had the work done I've been hearing bad things about the company I used so I was hoping someone on here could give me some advice.

Thank you.
 

Spoon

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Have you paid in full for this work?
Did you receive and paperwork (electrical certs) for this work?
What wattage lights are fitted?

Oh... I keep forgetting....
Welcome to the forum mate.
 

Pete999

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Hello,

I've recently had some outside lights fitted, there is about 10 of them, all LED. The electricans took the cable from the fuse board down into my basement void where other services are running and then out to the garden. Outside they have used armoured cable, 1.5mm, about 20-30meters in total I'd have thought. But in the basement void, it's about another 20m from the fuseboard end to the outside but they have used a 0.75mm 3 core white flex cable.

The circuit breaker is 6 amps.

I don't know whether that is good or bad but to me something isn't quite sitting right having a cable half the size of the armoured cable, it looks like they've used a cable very similar to the flex hanging down on my pendants for 20m.

Should I be concerned or is it ok? Since I have had the work done I've been hearing bad things about the company I used so I was hoping someone on here could give me some advice.

Thank you.
Welcome
 
  • Thread Starter Thread Starter
  • #4
Thanks for the reply!

Yes I have paid for the work but I was never given any paperwork from them.

The lights I think are 3.5 watt.
 
  • Thread Starter Thread Starter
  • #5
Have you paid in full for this work?
Did you receive and paperwork (electrical certs) for this work?
What wattage lights are fitted?

Oh... I keep forgetting....
Welcome to the forum mate.
Thanks for the reply!

Yes I have paid for the work but I was never given any paperwork from them.

The lights I think are 3.5 watt.
 
Have you raised your concerns with the person(s) that did the work?
 

Spoon

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Thanks for the reply!

Yes I have paid for the work but I was never given any paperwork from them.

The lights I think are 3.5 watt.
So you have about 35W in total. About 0.2A
1.5mm SWA cable is the smallest size you can get.
0.75mm 3 core white flex is rated for 6A.
Only think that might be an issue is volt drop but at less than 0.2A load then there shouldn't be a problem.

If this circuit for the 10 LED lights a new circuit? (is the 6A breaker new) or is it an existing breaker for the lights?
 
  • Thread Starter Thread Starter
  • #8
Have you raised your concerns with the person(s) that did the work?
I have tried to contact them but he wont pick up his phone or reply to my email.


So you have about 35W in total. About 0.2A
1.5mm SWA cable is the smallest size you can get.
0.75mm 3 core white flex is rated for 6A.
Only think that might be an issue is volt drop but at less than 0.2A load then there shouldn't be a problem.

If this circuit for the 10 LED lights a new circuit? (is the 6A breaker new) or is it an existing breaker for the lights?
Yes it's a new circuit, the house was re-wired maybe about 10 years ago and the fuse board had about 3 spare gaps in it with some plastic covers where the circuit breakers would be so I assume it's a new 6A one.

One of the reasons I was concerned, other than the fact it was half the size of armoured cable is because from what I have seen online it's not good practice to wire in a flex cable or that it should be fused down to 3A? I found it a confusing to be honest so I've probably got it completely wrong...
 

Spoon

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Also, as @peterhyper
I have tried to contact them but he wont pick up his phone or reply to my email.




Yes it's a new circuit, the house was re-wired maybe about 10 years ago and the fuse board had about 3 spare gaps in it with some plastic covers where the circuit breakers would be so I assume it's a new 6A one.

One of the reasons I was concerned, other than the fact it was half the size of armoured cable is because from what I have seen online it's not good practice to wire in a flex cable or that it should be fused down to 3A? I found it a confusing to be honest so I've probably got it completely wrong...
Ok, so it's a new circuit. Depending on where you are in the UK, this falls under Part P and the work needs to be notified to your Local Building Control Body.
Yes flex is not ideal for this circuit, but it's not 'unsafe'. 99% of electricians would not have used flex.
With a new circuit you should have received an Electrical Installation Certificate.
 
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Pete999

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Hello,

I've recently had some outside lights fitted, there is about 10 of them, all LED. The electricans took the cable from the fuse board down into my basement void where other services are running and then out to the garden. Outside they have used armoured cable, 1.5mm, about 20-30meters in total I'd have thought. But in the basement void, it's about another 20m from the fuseboard end to the outside but they have used a 0.75mm 3 core white flex cable.

The circuit breaker is 6 amps.

I don't know whether that is good or bad but to me something isn't quite sitting right having a cable half the size of the armoured cable, it looks like they've used a cable very similar to the flex hanging down on my pendants for 20m.

Should I be concerned or is it ok? Since I have had the work done I've been hearing bad things about the company I used so I was hoping someone on here could give me some advice.

Thank you.
Where are you situated, could come and give you an opinion if it's not to far from Northampton
 
  • Thread Starter Thread Starter
  • #11
Also, as @peterhyper


Ok, so it's a new circuit. Depending on where you are in the UK, this falls under Part P and the work needs to be notified to your Local Building Control Body.
Yes flex is not ideal for this circuit, but it's not 'unsafe'. 99% of electricians would not have used flex.
With a new circuit you should have received an Electrical Installation Certificate.
Oh okay, they never mentioned any kind of certification to me so didn't know that, I will send them another email asking for this.
I'm glad it's not technically unsafe and that does give me peace of mind a bit. Would you recommend having it fused down to 3A?


Where are you situated, could come and give you an opinion if it's not to far from Northampton
I'm in Portsmouth unfortunately but I appreciate the offer.
 

happysteve

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0.75mm flex is good up to 6A (BS7671 table 4F3A), no need to fuse down to 3A.
 
0.75 is inadequate for the purpose of fixed wiring minimum size for lighting is 1.0mm. If they have used this for the supply from the consumer unit this is incorrect and it needs replacing.
 

happysteve

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0.75 is inadequate for the purpose of fixed wiring minimum size for lighting is 1.0mm. If they have used this for the supply from the consumer unit this is incorrect and it needs replacing.
I disagree. Table 52.3.

(I wouldn't do the install like this, I should stress. And the flex needs proper termination with bootlace ferrules. But there's nothing in the Regs that says you can't do it this way.)
 

Pete999

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I disagree. Table 52.3.

(I wouldn't do the install like this, I should stress. And the flex needs proper termination with bootlace ferrules. But there's nothing in the Regs that says you can't do it this way.)
I disagree Steve table 52.3 stipulates 1mm2 minimum for lighting circuits, which in the case we are discussing 0.75mm3 flex has been utilised for that porpose
 
I disagree. Table 52.3.

(I wouldn't do the install like this, I should stress. And the flex needs proper termination with bootlace ferrules. But there's nothing in the Regs that says you can't do it this way.)
Yes Table 52.3, 1.0mm for lighting circuits. Whilst some allowance is allowed for final connections if the 0.75mm is direct into the consumer unit it is undersized.
 

happysteve

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Yes Table 52.3, 1.0mm for lighting circuits. Whilst some allowance is allowed for final connections if the 0.75mm is direct into the consumer unit it is undersized.
You have to read the table left to right.

The first column is "type of wiring system" and the first row is "non-sheathed and sheathed cables." If you're using this type of cable, then I agree minimum size is 1mm for lighting, 1.5mm for power (assuming copper).
The second row is "bare conductors" - not relevant here.
The third row is "non-sheathed and sheathed flexible cables." This is a different row from the first row, and there are different requirements. Under "use of the circuit" (2nd column) you've got "for a specific appliance" (not relevant here), and "for any other application", which is. 0.75mm.

So rather than reading it as, "lighting says 1mm, so 1mm", you start off by asking which type of cable, then what the application is, then the minimum size.
 
  • Thread Starter Thread Starter
  • #18
Yes Table 52.3, 1.0mm for lighting circuits. Whilst some allowance is allowed for final connections if the 0.75mm is direct into the consumer unit it is undersized.
So the flex cable needs to be replaced for 1mm cable?
Don't understand any of the recent posts, trying too!
 

Pete999

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You have to read the table left to right.

The first column is "type of wiring system" and the first row is "non-sheathed and sheathed cables." If you're using this type of cable, then I agree minimum size is 1mm for lighting, 1.5mm for power (assuming copper).
The second row is "bare conductors" - not relevant here.
The third row is "non-sheathed and sheathed flexible cables." This is a different row from the first row, and there are different requirements. Under "use of the circuit" (2nd column) you've got "for a specific appliance" (not relevant here), and "for any other application", which is. 0.75mm.

So rather than reading it as, "lighting says 1mm, so 1mm", you start off by asking which type of cable, then what the application is, then the minimum size.
Well having read the table from left to right I still say 1mm2 I/is the min for a lighting circuit.
 

happysteve

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Well having read the table from left to right I still say 1mm2 I/is the min for a lighting circuit.
Ok, let's try this:

Which of these two descriptions most accurately describes the "flexible cable" we're talking about? Is it:

(a) "Non-sheathed and sheathed cable,"

or

(b) "Non-sheathed and sheathed flexible cable."
 

Pete999

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So the flex cable needs to be replaced for 1mm cable?
Don't understand any of the recent posts, trying too!
w/Without the pleasure of seeing the install, and from what you have said so far, my advice would be to get it looked at by a competent Electrician
 
Ok, let's try this:

Which of these two descriptions most accurately describes the "flexible cable" we're talking about? Is it:

(a) "Non-sheathed and sheathed cable,"

or

(b) "Non-sheathed and sheathed flexible cable."
If 0.75mm was suitable for lighting circuits manufacturers would produce T&E in this size.
 

happysteve

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Great, so we go to that row of the table (near the top of page 145 in the blue book, or page 134 of the old yellow book). Now read across for application, is it:

(a) for a specific appliance? (no)
(b) for any other application? (yes)
(c) extra-low voltage circuits for special applications? (no)

Minimum size for (b) is 0.75mm

If 0.75mm was suitable for lighting circuits manufacturers would produce T&E in this size.
No, because T&E uses solid (or, for larger sizes) stranded copper conductors, rather than flexible conductors. The minimum size for these is 1mm, and for good reason - they'd be too easy to break if smaller than 1mm.

Have you ever wondered why the cpc on 1mm T&E is not smaller than 1mm? It's not because of the adiabatic. It's because it would break too easily.
 

happysteve

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... but in response to the original poster: the installation method is "unconventional" to say the least, you should certainly have got an Electrical Installation Certificate as the work involves the provision of a new circuit, and the work should have been notified to Building Control. Unless the flex has had bootlace ferrules put on the end of it before termination in the consumer unit, it has not been installed correctly.
 

Pete999

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... but in response to the original poster: the installation method is "unconventional" to say the least, you should certainly have got an Electrical Installation Certificate as the work involves the provision of a new circuit, and the work should have been notified to Building Control. Unless the flex has had bootlace ferrules put on the end of it before termination in the consumer unit, it has not been installed correctly.
Away from the discussion about 1mm or 0.75mm, who or what sort of person would wire the garden lights in 1.5mm3 SWA cable, and then lash it on to a length of 0.75mm2 flex, answers on a post card please.
 

happysteve

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(b) for any other application, no it is lighting. The cable is undersized.
Why would you take the rule for the minimum size of a different type of cable?

Ok, suppose for a completely different application, you were using bare conductors (second row), but you were using it for a lighting circuit rather than power. Minimum size for "power" for bare conductors is 10mm (copper), would you go "ah, but elsewhere in the table it says lighting 1mm, so I can use 1mm for lighting circuits if I use bare conductors"? No, of course not.

First sort out what sort of cable you're using: ignoring bare conductor cable, is it flex, or not? If flex, you look at what the use of the circuit is, and size accordingly. If not flex, you do the same. You don't pick and choose "use of circuit" and then apply it to the three different types of cable listed.
 
T

Toneyz

There could be a small chance that it is white FP200 but I am assuming that the OP has felt it and it is flex then its not good practice even if it is adequately fixed.
 

happysteve

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Yes the use of circuit is lighting no matter how much you juggle it. Bare conductor sizes are irrelevant.
I think we're going to have to agree to disagree then.

My logic, reading table 52.3 (ignoring bare conductors):

Is it flex, or not flex?

If not flex, minimum size = 1mm for lighting, 1.5mm for power.

If flex, minimum size = 0.75mm, unless specified in the product standard for a specific appliance.
 
Put some photos on of the wiring
 

happysteve

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I thought 0.75 flex was only allowed for pendant wiring etc?
You got a reg number for that? :)

The only thing I can see specific to pendant wiring is 411.3.1.1, which is about not having a cpc, rather than sizing: "A circuit protective conductor shall be run to and terminated at each point in wiring and at each axcessory except a lampholder having no exposed-conductive parts and suspended from such a point."
 
Never really comment, just enjoying reading. Just wondering with all comments if 1mm is minimum allowed for lighting, how come 0.75mm flex is supplied with most pendants, surely this must class as part of the lighting circuit?
 

PEG

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I'm going to have to go with Happysteve,on this one,purely on the basis of working backwards from a potential incident or investigation,the regs could not be straightforwardly used,to indicate an incorrect selection of materials,in this specific example.

The lighting issue evaporates,if the same circuit powered a garden sound system,of the same load ;)
 

Pete999

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Never really comment, just enjoying reading. Just wondering with all comments if 1mm is minimum allowed for lighting, how come 0.75mm flex is supplied with most pendants, surely this must class as part of the lighting circuit?
Not really fixed wiring though is it??
 
D

Deleted member 9648

Agree with Happysteve. Table 52.3 clearly states 'any other application' for 0.75mm minimum flexible cable as option 2 of 3. If it did not include lighting it would state 'any other application except for lighting'.
 
Ok...Lets be honest...no decent Electrician would run a 0.75mm flex from the board and connect it to a 1.5mm armoured.....Ask for EIC for new circuit and get him back to do it properly
 

Midwest

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0.75 is inadequate for the purpose of fixed wiring minimum size for lighting is 1.0mm. If they have used this for the supply from the consumer unit this is incorrect and it needs replacing.
I think I have to agree with westward here.

Here's a previous thread on the subject;


Just BS7671 being ambiguous again; as @Andy78 said #57 'in table 52.3 "for any other application" listed for flex actually should mean "for any other application (other) than those listed above" .

As the above thread, a flex for fixed wiring would also need to comply with 521.9.1 (BYB), which for the OP's benefit states;

'A flexible cable shall be used for fixed wiring only where the relevant provisions of the Regulations are met. Flexible cables used for fixed wiring shall be of the heavy duty type unless the risk of damage during installation and service, due to impact or other mechanical stresses, is low or has been minimised or protection against mechanical damage is provided. Note: Descriptions of light, normal and heavy duty types are given in BS EN 50565-1'.

Great these search engines on the web.:)
 

Midwest

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I've also found a piece on the Voltimum web site;


again for the OP's benefit it says;

With reference to Table 52.3 of BS 7671, the minimum conductor size for a radial final circuit for lighting, protected by an overcurrent protective device with a rated current or current setting (In) of 6 A, is 1.0 mm2 for thermoplastic (PVC) or thermosetting insulated cables having copper conductors.
The flexible cable between the ceiling rose or similar and the lampholder is permitted to have a minimum cross-sectional area of 0.75 mm2 (see Regulations 433.3.1(ii), 524.1 and Table 52.3). This flexible cable should preferably have 90 °C thermoplastic insulation.
 

Intoelectrics

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This install (though realistically not unsafe) is not in line with the BS 7671 so should therefore be rectified by the installer/designer because it cannot be "satisfactory" certified.
 
D

Deleted member 9648

I have had a long trawl through the relevant sections of the BBB and cannot see anything which specifically prevents the use of a flexible cable of 0.75mm csa. None of the above, including the voltimum statement supersede what it actually states in table 52.3. It clearly states that for any purpose other than a specific appliance or ELV the minimum is 0.75mm. However if anyone else can definitely show otherwise I'll accept my interpretation is wrong
 

Midwest

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As its been said before, the wording in the table is poorly written and should be clearer.

If one looks at the tables for ccc, the one for flexible cables has no installation methods, unlike that for insulated & sheathed flat cable; granted there are other tables for reference methods to determine ccc.

52.3 specifically mentions lighting & power circuits insulated & sheathed cables, but then doesn't for flexible cables. Why doesn't it just say for any other application for both cable types?
 

happyhippydad

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Well I don't often disagree with @westward10 but I think @happysteve has it with this one.

Table 52.3 is very clear. You don't just jump to the 'lighting circuits' part of the table. You HAVE to start at the beginning and work your way through a table. Therefore 0.75mm is acceptable in this scenario, however much we all dislike the idea.

edit.... although I met it doesn't meet the voltage drop requirements!
 
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DPG

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Good debate this one.
 

rapparee

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Well I'm sure the OP is none the wiser after this one.

I'd probably say it is OK as well. The lights are permanent LED fittings, it is not as if they are ceiling rose pendants and the low wattage bulbs can be replaced by old style incandescent bulbs.
 

Pete999

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Well I don't often disagree with @westward10 but I think @happysteve has it with this one.

Table 52.3 is very clear. You don't just jump to the 'lighting circuits' part of the table. You HAVE to start at the beginning and work your way through a table. Therefore 0.75mm is acceptable in this scenario, however much we all dislike the idea.

edit.... although I met it doesn't meet the voltage drop requirements!
what are you on HHD? have you been to a wholesalers lately and asked for a 100M drum of 0.75mm2 T and E with lots of qualified Sparkies' in attendance waiting for their free coffee?
 
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happyhippydad

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Well I'm sure the OP is none the wiser after this one.

I'd probably say it is OK as well. The lights are permanent LED fittings, it is not as if they are ceiling rose pendants and the low wattage bulbs can be replaced by old style incandescent bulbs.
We do tend to get a bit carried away don't we. Poor old OP doesn't know which way to turn, and also doesn't even know what OP means, so doesn't even know we're talking about him!
 

Des 56

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Interesting discussion,I have my opinion and it agrees with one of the competing views :)

Where I see a problem is with the op in his opening post describing the cable as they have used a 0.75mm 3 core white flex cable.

He is extra observant or meticulous with his estimate of flexible cable size because on the one hand he asks question of regulations and on the other hand he is better than me at sizing the difference between a 1.0mm flex and 0.75mm flex in situ

Something does not seem to add up,the story does not seem to be fully disclosed,it could very well have been 1.0mm flex from the outset :)
 
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Interesting discussion,I have my opinion and it agrees with one of the competing views :)

Where I see a problem is with the op in his opening post describing the cable as they have used a 0.75mm 3 core white flex cable.

He is extra observant or meticulous with his estimate of flexible cable size because on the one hand he asks question of regulations and on the other hand he is better than me at sizing the difference in a 1.omm and 0.75 flex in situ
Something does not seem to add up,the story does not seem to be fully disclosed
It may say the size of the cable on the flex......but you could be right in what your thinking
 

Intoelectrics

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I think what we can all agree on is, though not unsafe, it appears (assuming what the OP says is accurate) to be a bit of a bodge job. Without the full details and any pictures this is my personal opinion.
My advise to the OP is to get a honest second opinion from another qualified spark.
 
T

Toneyz

I think what we can all agree on is, though not unsafe, it appears (assuming what the OP says is accurate) to be a bit of a bodge job. Without the full details and any pictures this is my personal opinion.
My advise to the OP is to get a honest second opinion from another qualified spark.
I think a bodge job might be a bit strong description a bit orthodox maybe. Is it unsafe I don't think so but as posted without pictures it is hard to tell.
 
  • Thread Starter Thread Starter
  • #60
Interesting discussion,I have my opinion and it agrees with one of the competing views :)

Where I see a problem is with the op in his opening post describing the cable as they have used a 0.75mm 3 core white flex cable.

He is extra observant or meticulous with his estimate of flexible cable size because on the one hand he asks question of regulations and on the other hand he is better than me at sizing the difference between a 1.0mm flex and 0.75mm flex in situ

Something does not seem to add up,the story does not seem to be fully disclosed,it could very well have been 1.0mm flex from the outset :)
It says 0.75 on the cable, as well as some other letters and numbers.

I've been trying to get hold of the company but not had any luck, I said about the certificate and apparently he needs to come and take some details of the fuse board but doesn't have time to do it at the moment...apparently.

Anyway, I've arranged for another person to come and have a look at the work that's been done, when I told them about the 0.75mm cable they didn't seem impressed.
 

DPG

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Thanks for the update. Keep us posted.
 
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