Advice on work I've had done

[bryc-123]

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.

 

[happysteve]

(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.

 

[westward10]

Yes the use of circuit is lighting no matter how much you juggle it. Bare conductor sizes are irrelevant.

 

[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]

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.

 

[DPG]

I thought 0.75 flex was only allowed for pendant wiring etc?

 

[SparkyAndGeorge]

Put some photos on of the wiring

 

[happysteve]

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."

 

[Skys]

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]

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]

I thought 0.75 flex was only allowed for pendant wiring etc?

Dunno about that Mate, you should see the mess my 0.75mm2 shower circuit made of my mates new bathroom!!!!

 

[Pete999]

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??

 

[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'.

 

[Markyd]

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]

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;

0.75mm Flex into 6A MCB | Page 2 | on ElectriciansForums

Find 0.75mm Flex into 6A MCB Advice and Help. How-to 0.75mm Flex into 6A MCB in the UK Electrical Forum advice boards on ElectriciansForums.net | Free Electrical Advice - Electricians Forums: Electricians' Talk Forums. 0.75mm Flex into 6A MCB on ElectriciansForums.net Electrical Advice Forum.

www.electriciansforums.net

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]

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

Changes in Amendment 3 to BS 7671: 2008 relating to final circuits supplying lighting points

Amendment 3 to BS 7671: 2008 introduced changes in how the regulations relating to certain types of lighting installations are arranged. This article identifies these changes.

www.voltimum.co.uk

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.