circuits wired in flex?

[gap30]

hi all,

had a bit of a discussion with a guy at work today, carrying out a periodic and there was a circuit wired in flex at the DB, i seem to think this is a code 2 but cannot find anything in the regs to back this up?

is it ok for circuits to be wired in flex?

 

[dingledong]

as long as they are the correct size yes

 

[gap30]

ok thanks for reply

 

[Engineer54]

Depends on what type of ''Flexible'' cable your talking about!! I wouldn't call appliance type flexible cable, suitable for building wiring... But it seems anything goes these day's, so nothing really much surprises anymore on the forums Threads and posts!! ....lol!!

 

[Hawk81]

Can you tell me why you think that flex is not suitable for building wiring?

 

[Richard Burns]

Have a look at 521.9 this permits flexible cable if meeting the regs and of heavy duty type or mechanically protected.

I would not have though it would be a good idea, but it is still just a conductor.

For a PIR it would not be coded just because it was flex.

 

[madmac]

Listen, regardless of whether it's clearly defined in the regs or not, I agree with Engineer 54. It is bad practice and again sets a low standard of installation that no self respecting electrician would even contemplate putting their name to!!!
As for a PIR, I would note it down as deviation from the regs. because it is agreed practice to use recognised types of cables for "hard wiring" as we used to call it, before all this shoddy practice was introduced!!!
Next, people will be saying it's ok to use bell wire for fir alarms and it's ok to use multi core flex to carry 240v circuits alongside ELV circuits just because it's easier than running two seperate and segregated circuits!!!!

 

[malcolmsanford]

Mac it can't be a deviation if it is allowed in the regs can it mate.

Whether it is regarded as bad practice or not, if your doing a PIR and find a circuit wired in flex then you can't code it unless it is undersized or mechanically compromised in some way.

 

[SPARTYKUS]

Its used in the fabric of a motor home or canal boat. If anything it could be argued it have extra properties although i would be worried if vibration, etc was a concern in one's house!

However doesnt feel nice as madmac says, I suppose not the done thing

 

[roukel01]

I would never do it, but this came up when I was doing my 2391. The guy taking the course said "as long as it is installed, inspected and tested to the regs, then there's no problem in using flex"

Again, I wouldn't do it, but if you are carrying out a PIR, the only time it would be noted as an observation, is if there is a problem with the circuit or installation methods.

 

[Hawk81]

This makes me laugh, the ones who are against it just keep saying its bad practice. Sorry lads it's not. It's not a deviation, or against the regs. It just something you personally don't like. I happen to agree in the fact that I would not wire circuits in a house in flex but I wouldn't try and force my opinion on others. The facts are it is up to the individual and that is it

 

[SPARTYKUS]

No forcing of opinion on my part hawk, its a forum, just expressing!

 

[Hawk81]

I was not meaning you

 

[i=p/u]

i wire lighting circuits in flex long as its clipeed through its length, but i do use t&e to switch

 

[Mr.Ian]

the trouble with flex is when you get someone that cuts some of the strands of the multicore conductor when stripping it, they then end up with a smaller CSA and a higher resistance and lower current capacity without knowing it. Also over time when terminating more and more strands will break off making the situation worse. I can understand it being used in certain lighting situations but certainly not under plastered walls.

 

[mogga]

it depends on the CCC and other properties of the"flex" more and more shop fitting ,motor rooms,bouler rooms are being done with YY and SY "flex" but a lot are wrongly installed specialy the glanding and earthing of braids
Then there is the question of colours in 5 core YY all cores are black with numbers on them many PIRs iv seen no other markings put on the cores not even on the earth its Shoddy instaqllers who give a bad name to this stuff the YY,SY are good in many other ways when installed CORRECTLY but its easy to mess up the installation of these

 

[Engineer54]

As i said, if were talking ''appliance'' type flexible cable, that isn't, ...as far as i know anyway, been manufactured or classified for ''hard wiring'' then it shouldn't be used or seen in that context!! There are plenty of flexible types of cabling that IS classified/manufactured for hard wiring, .... i don't think anyone can or have objection to those cables being used. But if were talking about the appliance flexible lead type of cable, then things have gone way down hill... That's like installing a general off the shelve extension lead as the permanently supply of a circuit to my mind!!! Very Professional, ....NOT!!!!

 

[Edd]

On holiday a few years ago (more like 10) in menorca there was a hotel that had been half built and never finished!
The whole place had been wired in flex.. I did enjoy exploring around..
So anyway It may not be what we all Like, but as our colours have already changed I do wonder how long it will be till we Have to wire in flex.. Im of the old school and if i find flex im straight into thinking DIY even though as others have stated its not against regs.. we all need to move foward

 

[Engineer54]

On holiday a few years ago (more like 10) in menorca there was a hotel that had been half built and never finished!
The whole place had been wired in flex.. I did enjoy exploring around..
So anyway It may not be what we all Like, but as our colours have already changed I do wonder how long it will be till we Have to wire in flex.. Im of the old school and if i find flex im straight into thinking DIY even though as others have stated its not against regs.. we all need to move foward

It may have looked like common flex, but more probably wasn't!! They use different wiring cables in Spain to those used in the UK. Some can certainly look like flex, that's for sure!! lol!!

I'm not exactly sure that common appliance flex does comply to the Reg's?? As it isn't rated or manufactured as a hard wiring building cable, ...It is what it is, appliance cord!!!

 

[jase]

so all you guys who dont like using flex run all your outside lighting in t+e then? clipped dierect to the outside of a house looks great? and doenst perish at all?
and on a comercial not i have seen plenty of cctv systems that use twin coax and 2 core flex cables.

 

[Daveyboy]

I've seen a few offices wired in flex!

 

[Engineer54]

so all you guys who dont like using flex run all your outside lighting in t+e then? clipped dierect to the outside of a house looks great? and doenst perish at all?
and on a comercial not i have seen plenty of cctv systems that use twin coax and 2 core flex cables.

Oh well then, ....that must make it all, all right then!!! Off you go then, and on your next re-wire you can use common flex chord to wire the house, lights, sockets, ...you name it. ...Geezus!!!

 

[dingledong]

what is common flex cord and whats with appliance flex. never seen appliance fley longer than a metre. i dont think 2.5 flex is appliance flex do you are you all the new breed electricain so cos you dont like it you tell the customer ist wrong and that part needs rewiring. ive not used flex to rewire a gouse but of course have run flex where i thought it was appropiate

there is no reg against using flex as long as its the correct size and as for strands coming of when stripping . .well practice a bit more and strip it correctly easy hmmn

 

[Big n Daft]

Plumbers wire in flex...................nuff said.

 

[Engineer54]

what is common flex cord and whats with appliance flex. never seen appliance fley longer than a metre. i dont think 2.5 flex is appliance flex do you are you all the new breed electricain so cos you dont like it you tell the customer ist wrong and that part needs rewiring. ive not used flex to rewire a gouse but of course have run flex where i thought it was appropiate

there is no reg against using flex as long as its the correct size and as for strands coming of when stripping . .well practice a bit more and strip it correctly easy hmmn

There are plenty of kitchen appliances wired with 2.5mm flex for god's sake, and some even in 4mm flex in commercial kitchens. And where pray, do you consider appliance/common flex is appropriate then?? ....Running under floorboards thru joists interconnecting between downlights, maybe down to the switch positions??

Nothing wrong with connecting, say from a lighting JB to a down-light or fitting with a short length of flex with some form of heat resistant sleeving on the connection leads... But, running round the ceiling under floorboards connecting up several down-lights as the circuit wiring isn't what the flexible cable was made or intended for!!

''Easy'' just about sums up what it all comes down too

Common flex = Appliance flex

 

[dingledong]

most appliances are wired in 1.5 flex
wouldn't need heat resisting sleeving if you used heat resisting flex and flec could be used to run around cielings for say down lights
where does it say its wrong ???
and i dont agree with your terminology common flex or appliance flex. is that what you would call it when you went into your wholesaler ?

 

[dingledong]

got to stop drinking when i'm on here my typing is bad

 

[morph]

flex is fine in the right application, ie outside or final connections to immersion heater or from rock light fittings etc

 

[Hawk81]

Someone please tell me the major difference in having flex and twin and earth clipped above a ceiling? A serious and proper answer not rubbish like flex was not intended for this use or it's bad practice

 

[Engineer54]

most appliances are wired in 1.5 flex
wouldn't need heat resisting sleeving if you used heat resisting flex and flec could be used to run around cielings for say down lights
where does it say its wrong ???
and i dont agree with your terminology common flex or appliance flex. is that what you would call it when you went into your wholesaler ?

In your case then, ...We'll call it ''hard wiring''!! ...OK

Personally, i don't really care what or where you, or anyone else uses it!! Just don't try and come here and convince us, that this practice is perfectly normal cause it isn't and never has been. What it is, ....is easy installation!!

 

[Hawk81]

In your case then, ...We'll call it ''hard wiring''!! ...OK

Personally, i don't really care what or where you, or anyone else uses it!! Just don't try and come here and convince us, that this practice is perfectly normal cause it isn't and never has been. What it is, ....is easy installation!!

Brilliant and informative answer.

 

[Engineer54]

Someone please tell me the major difference in having flex and twin and earth clipped above a ceiling? A serious and proper answer not rubbish like flex was not intended for this use or it's bad practice

What can't you understand then, about not being manufactured for the intention for use as hard wiring?? Is that not a good enough reason for you? If you want to use a flexible cable above and around ceilings as you circuit medium, use a flexible cable that IS intended for use as a hard wiring cable. It's simple logic really!!!

 

[Mr.Ian]

there is no reg against using flex as long as its the correct size and as for strands coming of when stripping . .well practice a bit more and strip it correctly easy hmmn

Just to set the record straight, after 30 odd years of stripping 'flex' for terminating I do not need to practice, and as far as i'm aware any multi strand flex when disconnecting for testing and re connecting will if care isn't taken get damaged.

 

[Hawk81]

What can't you understand then, about not being manufactured for the intention for use as hard wiring?? Is that not a good enough reason for you? If you want to use a flexible cable above and around ceilings as you circuit medium, use a flexible cable that IS intended for use as a hard wiring cable. It's simple logic really!!!

Where do you get your information on what flex is manufactured intention is?

 

[Big n Daft]

Leaving aside the can you or cant you issue..........................
How much is flex compared with twin n skin????

 

[Engineer54]

Where do you get your information on what flex is manufactured intention is?

H05 type flexible cables are generaly intended to supply appliances and equiment. I'm not too conversant with European cable designation numbers these days, more conversant with the Yank/Asian systems.... But i think the attached is a pretty good example of what i'm talking about, if these are the cable designation types that are being used for hard wiring....

Application: 318-Y Cable H05VV-F to BS6500For use in household appliances such as washing machines, spin dryers and refrigerators. Generally unsuitable for outdoor use or industrial applications.Standards:
0.5 - 2.5mm² to BS6500,
4.0mm² to BS7919
6.0mm² generally to BS7919
VDE28
CENELEC HD21.5


Application: 309-Y Flexible Cable H05V2V2-F to BS6500Supply leads for use as 318-Y but particularly for use in high temperature zones, for internal wiring or supply cords to electrical apparatus. Not suitable for outdoor use.Standards:BS6500, BS7919 above 4.0mm²Conductor:Class 5 flexible plain copper to BS EN 60228:2005 (previously BS6360)InsulationVC (Polyvinyl Chloride) Type TI 3 to BS7655SheathVC (Polyvinyl Chloride) Type TM 3 to BS7655Colour:WhiteVoltage Rating:300/500VTemperature Rating:0 to +90°CMinimum Bending Radius:6 x overall diameterCore Identification:
2 Cores: Blue, Brown
3 Cores: Green/Yellow, Brown, Blue
4 Cores: Green/Yellow, Brown, Black, Grey
5 Cores: Green/Yellow, Brown, Black, Grey, Blue
RoHS Compliant



Application: 318-TQ Cable H05BN4-FFlexible cords suitable for use in domestic premises, kitchens and offices. Also suitable for use in hot situations such as immersion heaters. Good resistance to oil and grease.Standards:BS6500, VDE 0282Conductor:Class 5 flexible plain copper conductorsInsulation:EPR (Ethylene Propylene Rubber) CompoundSheath:HOFR Compound (Heat & Oil Resistant, Flame Retardent)Sheath Colour:WhiteVoltage Rating:300/500VTemperature Rating:-35°C to +85°CMinimum Bending Radius:6 x overall diameterConductor Identification:
3 Cores: Brown, Blue, Green/YellowRoHS Compliant

 

[sbrown2]

As somebody who has had only a year and a half in the domestic sector, and having a mining background, I like the idea of using flex instead of single wired armoured!!!!!!

 

[Guest112]

ive had this conversation with engineers in the past and they reckon the only reason we dont always use flex is because of cost, apart from that there isnt anything wrong with it apparently.

and as for numptys cutting strands out when striping ends is this any different to them cutting into a solid core slightly when stripping solid strand cables? #

I worked in a steelworks alongside a big italian electrical contracting firm who were also pulling in and connecting large cables but every cable they pulled in were large flexible cables much easier to work with on a larger scale, have better current carrying capabilities and also better for terminating.

not that I use flex to hardwire from dbs but ive seen it done especially in office environments, but i have used flex between lighting in office situations at the clients request,

and as for "appliance flex" i dont know what e54 means there but when i order a drum of flex from the wholesalers it just says flexible cable on it and i just make sure its the right size for its purpose and is a reputable brand.

flex is great in situations where movement is expected like i said in office ceilings but i personally hope it doesnt become a form of hard wiring because i can strip a t+e quicker than i can a flex

 

[Marvo]

H05 type flexible cables are generaly intended to supply appliances and equiment. I'm not too conversant with European cable designation numbers these, more conversant with the Yank/Asian systems.... But i think the attached is a pretty good example of what i'm talking about, if these are the cable designation types that are being used for hard wiring....

Application: 318-Y Cable H05VV-F to BS6500For use in household appliances such as washing machines, spin dryers and refrigerators. Generally unsuitable for outdoor use or industrial applications.Standards:
0.5 - 2.5mm² to BS6500,
4.0mm² to BS7919
6.0mm² generally to BS7919
VDE28
CENELEC HD21.5


Application: 309-Y Flexible Cable H05V2V2-F to BS6500Supply leads for use as 318-Y but particularly for use in high temperature zones, for internal wiring or supply cords to electrical apparatus. Not suitable for outdoor use.Standards:BS6500, BS7919 above 4.0mm²Conductor:Class 5 flexible plain copper to BS EN 60228:2005 (previously BS6360)InsulationVC (Polyvinyl Chloride) Type TI 3 to BS7655SheathVC (Polyvinyl Chloride) Type TM 3 to BS7655Colour:WhiteVoltage Rating:300/500VTemperature Rating:0 to +90°CMinimum Bending Radius:6 x overall diameterCore Identification:
2 Cores: Blue, Brown
3 Cores: Green/Yellow, Brown, Blue
4 Cores: Green/Yellow, Brown, Black, Grey
5 Cores: Green/Yellow, Brown, Black, Grey, Blue
RoHS Compliant



Application: 318-TQ Cable H05BN4-FFlexible cords suitable for use in domestic premises, kitchens and offices. Also suitable for use in hot situations such as immersion heaters. Good resistance to oil and grease.Standards:BS6500, VDE 0282Conductor:Class 5 flexible plain copper conductorsInsulation:EPR (Ethylene Propylene Rubber) CompoundSheath:HOFR Compound (Heat & Oil Resistant, Flame Retardent)Sheath Colour:WhiteVoltage Rating:300/500VTemperature Rating:-35°C to +85°CMinimum Bending Radius:6 x overall diameterConductor Identification:
3 Cores: Brown, Blue, Green/YellowRoHS Compliant

'Flex' is an awful term. I also sometimes refer to HO5 AND HO7 neoprene trailing cabling as flex but I think what they're referring to as flex in this thread here is what we call 'PVC cabtyre'.

 

[gap30]

wow! this thread opened a can of worms.

I frown on flex in db's to hard wire circuits, i know there is no reg against it but it smacks of diy to me, it seems that most sparks are split on this one.

anyway i wont be listing it as a remedial anymore, fack it i am starting to lower my standards these days....

 

[Ric2013]

Plumber here. I know this is an old thread, but still interesting.

From my perspective, heating controls are probably largely wired with flexible cable because we often need 4 cores, or 4 cores and earth.

For example, to reach distant motorised zone valves, or to carry L(p) L(ch) L(dhw) N(p) and E between a wiring centre and a programmer. I personally dislike running two parallel T+Es between 2 enclosures, not so much because it's a waste of materials and time, but because it seems somehow wrong and gives me an extra earth to terminate in busy enclosures.

3C+E is available as a solid cable, but I'm not sure that 4C+E is, or not that I've seen. So I'm forced into a dilemma: double up on solid cables, or use flexible cable. Any suggestions for improvement are welcome, and if a good spark in Colchester is on here that actually understands heating controls, then I may have some work for them some way down the line, if they want it.

 

[littlespark]

Old, @Ric2013 ?
It’s practically Jurassic!

I only recognise one name so far.


I think it was mentioned that although compliment, flex is more expensive, and therefor only used in short lengths to appliances or equipment.

In the instance of heating controls…. Most come with flex already attached and it’s a job of connecting all the ends together in the wiring centre…. (Or as we call them- “joint boxes”)

If there’s a longer length required, say to a room stat, then it would normally be 6243y 3core and earth.

 

[Ric2013]

Old, @Ric2013 ?
It’s practically Jurassic!

I only recognise one name so far.


I think it was mentioned that although compliment, flex is more expensive, and therefor only used in short lengths to appliances or equipment.

In the instance of heating controls…. Most come with flex already attached and it’s a job of connecting all the ends together in the wiring centre…. (Or as we call them- “joint boxes”)

If there’s a longer length required, say to a room stat, then it would normally be 6243y 3core and earth.

My personal, unqualified person's feeling, is that I agree that cost is probably the main (although not the only) driver behind the UK's continued use of solid core flat cable.

How would I connect to a 2 port valve with 6243 though? I need:

N(p)
L(call from stat)
L(p)
L(switched from "L(p)" by microswitch inside the 2-port valve)
Earth (not always)

which is 4-core and earth. We're back to 2 parallel lengths of 6242 cable (which is normally how I would do it - one cable is a switch wire and the other carries the live and neutral to power the 6W valve motor). In practice, you can get a bit of flexible cable and a Wago box and extend the tail, and I'm thinking this is a better solution in a way, the beauty of this being that future tradesmen will know that everything in that cable core goes to the same destination (not sure if this also reduces the EMF created compared with two parallel 6242s?).

Ideally, everything would be close to the joint box and all as you say above. In practice, houses evolve and it's easier to rewire than repipe. This means cylinder stats can often be remote from the programmer and the hypothetical joint box ends up being split between several enclosures. For example, if the cylinder stat and zone valve for the hot water are one end of a house, it makes sense to have a box near the two to switch the switched live to the valve motor rather than run an extra length of 6242 to act as a pair of switch wires all the way back from the joint box if that is at the other end of the house. But you still need 4 cores and earth between the 'main' and 'secondary' joint boxes.

My understanding was that if flexible cable is used it should be visible throughout its length, but not sure who made that rule and how precisely they defined 'visible', nor what happens when the only place the already-attached-flex HAS TO start under the floor because that is where the 2-port valve is or realistically has to go. Quite happy to run my concealed control cables in 6242 and 6243 (in fact, I usually do), but would be nice to know exactly why I'm doing it and when I have to do it, and can quite understand why many don't. (Better still I'd get a local sparky if I knew one that both understood heating controls and was interested in doing the work.)

Reason I bring this all up is #24. I find the plumbers vs electricians thing an example of what is wrong with the construction industry. I've heard your points of view and I thought you might appreciate a bit of insight from the other side. And interested... would you really run two number 2-core T+E rather than a 5 core flexible cable?

 

[nicebutdim]

Solid multicore cables are available and widely used, although not so much in domestic installations.

 

[Lucien Nunes]

It's an interesting discussion and your points are well reasoned. Much of the historical comment on the thread was rather polarised. It was from a time when there were two distinct and cliquey schools of thought on this forum about many topics which tended to override logical, fact-based discussion.

3C+E is available as a solid cable, but I'm not sure that 4C+E is, or not that I've seen

Not as flat T+E, but fire performance cable ranges usually include a 4C+E option as does NYY-J. And indeed many European styles of cable.

would you really run two number 2-core T+E rather than a 5 core flexible cable?

No, but I don't work in the domestic sector so I hardly ever use 6242. Conversely, 4C+E FP is a stock item for me. If I didn't have that, I would be happy with 3185Y. I also tend to work abroad at times so I even keep continental wiring cables on the shelf. And in an ideal world I would be happiest wiring it in 4L1 MICC.

(not sure if this also reduces the EMF created compared with two parallel 6242s?).

Not many people seem to have taken this into account until it was highlighted in the regs, although the phenomenon has always been there. TBH if the 2x 2C+E are adjacent, there's not much in it and I wouldn't worry about it. And in some cases each cable is a complete circuit (e.g. your motorised valve motor cable / switch cable example.)

 

[Ric2013]

It's an interesting discussion and your points are well reasoned. Much of the historical comment on the thread was rather polarised. It was from a time when there were two distinct and cliquey schools of thought on this forum about many topics which tended to override logical, fact-based discussion.

Thanks for your kind attitude - and the explanation! Actually, everyone who has replied to me has been very helpful and it is appreciated. I may not be an electrician (and I prefer to leave that side to others who have the right knowledge and tools... when I can), but it's really good to have a bit more understanding in the hope that any small bits I may end up taking on myself will be OTT (from lack of knowledge of what I could get away with) rather than bodged, even though they may not look as tidy as I'd like.

Not as flat T+E, but fire performance cable ranges usually include a 4C+E option as does NYY-J. And indeed many European styles of cable.

Just Googled NYJ-J. It looks to be a solid cored round cable. Presumably that can be installed in much the same way as 6242 and simply stripped and terminated inside an enclosure? Looks to be a good option, if so. Thank you.

Not many people seem to have taken this into account until it was highlighted in the regs, although the phenomenon has always been there. TBH if the 2x 2C+E are adjacent, there's not much in it and I wouldn't worry about it. And in some cases each cable is a complete circuit (e.g. your motorised valve motor cable / switch cable example.)

I've always wondered about that. I suspected that it might be the case if the cables were adjacent, but I'm happier hearing it from you. I knew an adjacent live and neutral through an appliance (motor, or lamp etc etc) essentially cancelled out, but, out of interest, is that the same for a switch cable i.e. where you have a live to a switch, and a switched live returning from the switch?

 

[Lucien Nunes]

Yes, any two equal currents (equal in both magnitude and phase) flowing in opposite directions will cancel. Or indeed any net zero sum of currents in any combination of conductors. I.e. if all the conductors serving any device or combination of devices run together, there will be no net longitudinal current (as per Kirchhoff's first law.) The EMF radiation (and in the case of a signal cable, susceptibility) will cancel better if the two cores occupy the same line through space. This can be achieved by making them coaxial, or by twisting them together so that they orbit around a common centre line. Both methods will be familiar in applications such as aerial and data cables, but the same technique can be used in very critical technical environments to minimise the fields radiated by power cables.

With normal power circuits, it starts to become of interest when there are large areas enclosed within current loops due to wide spacing between the two conductors forming a circuit, and/or the current contains higher harmonics that radiate easily. In a domestic setting, this normally occurs with 'traditional' 2-way switching, and with single-core sheathed wiring where the line loops via the switches but the neutral via the lights.

When I was about 14, I installed some lighting wiring using surplus 2-core MICC. With multiple switched circuits and fixtures but only two cores per cable, I did some creative reassignment of the conductors as they passed through fittings, to minimise the total number of cable runs. Some carried net zero longitudinal current but others had slightly different currents in the two conductors due to serving different numbers of points. Some of the lights were fluorescents with wirewound ballasts, which create a peaky waveform. I soon found that switching these on obliterated all AM radio reception within 20 feet of the wiring. The fluos radiate by themselves, but the loop aerials formed by my 'optimised' wiring runs made them worse.

 

[davesparks]

My understanding was that if flexible cable is used it should be visible throughout its length,

Wow, that's a very old regulation! It was indeed a requirement once upon a time, possibly not since the 13th edition, that installed flexible cables be short and visible throughout there length.
As I understand it this requirement was due to the less than ideal insulation available for cable manufacture at the time and it being somewhat more prone to failure.
This regulation is long gone, along with the one limiting the length of installed flexible cable.