| Ask The Trades | |
|
https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl
DIY Forum >> Electrical Questions >> flex or not flex . i am comflexed https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1222447250 Message started by wigglesniggle on Sep 26th, 2008, 5:40pm |
|
|
Title: flex or not flex . i am comflexed Post by wigglesniggle on Sep 26th, 2008, 5:40pm I was adding a new socket to the living room, as there was only two in the room. I split the ring main and added the additional ciruit. The cable was taken under the wooden floor boards. To the other side of the room. Then inbedded in the wall to where it was terminated in its new socket. I wanted to go for overkill so I selected a cable which had equal to or better then the current carrying capacity of the normal 2.5 T& E and a one at that time I thought was easier to manipulate, and was protected against inviromantal effects ie the cable lying in wet soil under the floor. The cable more expensive and was flex type. This for years has served well. Until an inspection and test was carried out on the property and as it was a flexible cable it was failed out right. Why ??? I was taught that if you wanted to you could rewire your house out in busbars if they were capable of carrying the current, and you could aford it. Can some one give me there educated point of view please. |
|
Title: Re: flex or not flex . i am comflexed Post by cosbycarl on Sep 26th, 2008, 5:51pm Electricians are governed by regs and the regs state we cannot use flex for the purpose for which u have described, dont actually know the reason why tho? I myself would like to know!! |
|
Title: Re: flex or not flex . i am comflexed Post by Lectrician on Sep 26th, 2008, 6:33pm For a start, you are not meant to place a stranded and a solid conductor in the same terminal. If you had a socket such as the RRP crap, then these have two terminals for each L N and E, and you could likely get away with it. Wiring fixed wiring in flex is a 'dirty' practice even so ;-) |
|
Title: Re: flex or not flex . i am comflexed Post by cosbycarl on Sep 26th, 2008, 7:05pm Lectrician wrote on Sep 26th, 2008, 6:33pm:
How come? Is it because either of the conductors can become loose in the terminal? and does that apply to flat t&e stranded? Do they still sell flat t&e stranded for 1.0, 1.5 and 2.5mm cables? Have never come across it wen buying cables other than 4mm and upwards. I take it a rewire is in order if you come across a house with stranded and solid cables used in the same ring circuit etc...? C |
|
Title: Re: flex or not flex . i am comflexed Post by Lectrician on Sep 26th, 2008, 7:08pm Stranded cable is fine. It's the flexible cables that should not share a terminal with cable. This has been a big ish issue recently during inspections, and Ashley Rock have bought out a new JB to overcome the issue when doing downlights with transformers with flex ends. They are nice and thin, have cord restraignt, 4 sets of terminals in a row similar to pendents. |
|
Title: Re: flex or not flex . i am comflexed Post by ChubbyPhaseWire on Sep 26th, 2008, 7:14pm wrote on Sep 26th, 2008, 5:51pm:
Take a look at 521.9.3 ;) |
|
Title: Re: flex or not flex . i am comflexed Post by cosbycarl on Sep 26th, 2008, 7:47pm cool, thanx lec and chubby |
|
Title: Re: flex or not flex . i am comflexed Post by Twobarrows on Sep 27th, 2008, 9:01am wrote on Sep 26th, 2008, 7:14pm:
Any chance you could actually add a little value & post the text of that reg? |
|
Title: Re: flex or not flex . i am comflexed Post by wigglesniggle on Sep 28th, 2008, 11:17pm [smiley=wacky.gif] Thank you CHUBBYPHASEWIRE for pointing me in the right direction and putting my head back in the books. I have now spent a lot time trawling through the Regs and am hard put to find where it forbids the use of flexible cable for fixed circuits. To the contrary. Now I am led to believe that the data concerning the cross sectional area of cable given in the Regs, after all the calculations are worked out for the given circuit, give the minimum size of cable that can be used for that circuit. - Yes? One could then, if rich or mad, decide to use a larger more expense and less cost effective cable to complete the circuit in question. (Predicting the IEE 21st edition). In interpreting 521.9.1, see below, I believe that if the used flex was superior to the 2.5 twin and earth. Then the (521.9.1). below criteria of the regs was met. Regs 17edition (page 98) (521.9.1). A flexible cable or flexible cord shall be used for fixed wiring only where the relevant provisions of the regulations are met. Regs 16 edition (page 77) (522-08.06). “A flexible wiring system shall be installed so that excessive tensile and torsional stresses to the conductors and connections are avoided.” I haven't found anywhere in the Regulations, Yet, that prohibits a stranded and a solid conductor in the same terminal. What a Pandora box. Electricians are governed by regs. Yes! But these are by way of default deemed to be the minimal acceptable standard and what electrician worth his salt wants to measure himself up to the “acceptable minimal standard” . Lectrician thank you. I will look around for a suitable joint box to segregate the wires from each other. Many thanks looking forward to peoples replys thank you all. |
|
Title: Re: flex or not flex . i am comflexed Post by Nick_Miles on Sep 29th, 2008, 11:00am wrote on Sep 26th, 2008, 7:14pm:
Where does that say that it can't be used :-? |
|
Title: Re: flex or not flex . i am comflexed Post by ChubbyPhaseWire on Sep 29th, 2008, 4:51pm wrote on Sep 28th, 2008, 11:17pm:
:o |
|
Title: Re: flex or not flex . i am comflexed Post by sparky415 on Sep 29th, 2008, 5:41pm How about reconnecting it using either bootlace ferrules or a bladed crimp? :) |
|
Title: Re: flex or not flex . i am comflexed Post by wigglesniggle on Sep 29th, 2008, 9:23pm ha . Now thats what i call thinking outside of the BOX . 8-) cool |
|
Title: Re: flex or not flex . i am comflexed Post by squirrel on Sep 30th, 2008, 12:46am wrote on Sep 29th, 2008, 9:23pm:
More like thinking outside of the BOOKS |
|
Title: Re: flex or not flex . i am comflexed Post by sparky415 on Sep 30th, 2008, 6:17am Good or bad thinking Squirrel? |
|
Title: Re: flex or not flex . i am comflexed Post by Lectrician on Sep 30th, 2008, 6:26am I cant see socket back boxes being deep enough to allow you to use furrules :-/ RPP who are part of proteous make some really horible sockets, which do however have two terminals for each of the live neutral and earth. |
|
Title: Re: flex or not flex . i am comflexed Post by sparky415 on Sep 30th, 2008, 6:30am Good point |
|
Title: Re: flex or not flex . i am comflexed Post by Goodsparks on Sep 30th, 2008, 6:12pm You could use ferrules, sockets with additional terminals, through crimps onto a solid / stranded cable, or if the run is as straightforward as you say, just replace the run with a more suitable cable. Because flex isn't generally specified for installation use, you'll have trouble finding current ratings / volt drop ratings for the usual installation reference methods. (In trunking / insulating wall / clipped direct etc) I think its one of those areas, as Lec says its not normal and doesn't 'feel' right so generally would be picked up as a deviation and classed as unsatisfactory. Flex is ok for caravan wiring though i seem to remember ;) Paul |
|
Title: Re: flex or not flex . i am comflexed Post by wozzy on Sep 30th, 2008, 11:09pm using flex is obviously not good practice, but how can it be a 'fail out right' on a periodic? surely it would be a code 4? and therefore still satisfactory? |
|
Title: Re: flex or not flex . i am comflexed Post by Lectrician on Oct 1st, 2008, 6:21am I think that is the general concensus - It would be a code 4. |
|
Title: Re: flex or not flex . i am comflexed Post by dingbat on Oct 1st, 2008, 8:47am wrote on Sep 28th, 2008, 11:17pm:
Exactly. And, because its use is NOT a deviation in itself, no recommendation code should be used (provided, of course, that it satisfies the requirements of the regs). It is incorrect to comment on preferences, myths and fables in a PIR; all observations must be supportable by one or more actual regulations. You said, "as it was a flexible cable it was failed out right.". I would be interested to hear how your 'competent person' justified that assessment. wrote on Sep 28th, 2008, 11:17pm:
And you won't. But you should consider the requirements of Section 526, especially 526.1 and 526.2, items (ii), (iii) & (iv) |
|
Title: Re: flex or not flex . i am comflexed Post by supra59 on Oct 13th, 2008, 8:13pm so why not just solder the ends of the flex just a thought :-? |
|
Title: Re: flex or not flex . i am comflexed Post by cosbycarl on Oct 13th, 2008, 8:38pm Why not just twist the ends of the flex and double them over (use pliers to compress them a bit more too), also double the solid ends over and then you will have a nice tight fit!! Thats what i do, when wiring boilers you have a mixture of flat twin and 5, 4, or 3 core flex, you wouldnt pull that up in a periodic? I know i wouldn't. |
|
Title: Re: flex or not flex . i am comflexed Post by LSpark on Nov 23rd, 2008, 7:42pm It concerns me that the author of the post considers a flexible cable more suitable than a 2.5mm 6242Y twin & earth cable for domestic fixed wiring, and that this has not been addressed. Both flexible cables and solid or stranded twin & earth cables have there purposes in domestic situations, but should be used appropriately, and to the minimum size requirements of the regulations as already stated. |
|
Title: Re: flex or not flex . i am comflexed Post by cosbycarl on Dec 22nd, 2008, 10:18pm I would like to add that i have read that flex cables have to be visible throughout their length, which is why its not suitable for domestic installations where wiring cables under floorboards etc... is common place. When i read this, it reminded me of somebody actually telling me this quite a few years back now, when i asked the question as to why we didnt use it for rewires. |
|
Title: Re: flex or not flex . i am comflexed Post by dingbat on Dec 23rd, 2008, 7:32am wrote on Dec 22nd, 2008, 10:18pm:
And I have to ask, Carl, where did you read that? (You may have seen 413.3.4 and not realised that section 413 only applies to electrical separation.) |
|
Title: Re: flex or not flex . i am comflexed Post by Lectrician on Dec 23rd, 2008, 7:36am It has always been one of those things taught at college, and is no doubt in some books somewhere, but there is no mention of this specifically in the regs. Not sure if there ever was. I can remember being taught this at college though. They also frowned heavily on clipping flex. For example, the spur feeding a heater should be close enough and well situated for the flex to leave the spur and enter the heater without need to clip. |
|
Title: Re: flex or not flex . i am comflexed Post by Lectrician on Dec 23rd, 2008, 12:48pm Thanks for the info Chubbs. Good to see words accompanying the smilies :-* Perhaps it is Ding logged into your account ;D All the best :) |
|
Title: Re: flex or not flex . i am comflexed Post by ChubbyPhaseWire on Dec 23rd, 2008, 12:54pm :) |
|
Title: Re: flex or not flex . i am comflexed Post by Lectrician on Dec 23rd, 2008, 1:00pm Thats more like it :P |
|
Title: Re: flex or not flex . i am comflexed Post by ChubbyPhaseWire on Dec 23rd, 2008, 1:02pm Lectrician wrote on Dec 23rd, 2008, 12:48pm:
:-X |
|
Title: Re: flex or not flex . i am comflexed Post by londonman on Dec 23rd, 2008, 5:48pm wrote on Oct 13th, 2008, 8:13pm:
Mechanically it creates a potential fracture point at the junction of the soldered bit and the rest of the flex. |
|
Title: Re: flex or not flex . i am comflexed Post by cosbycarl on Dec 23rd, 2008, 8:46pm dingbat wrote on Dec 23rd, 2008, 7:32am:
I think you know the answer to that one ding, that crap book i recently purchased! ;D |
|
Title: Re: flex or not flex . i am comflexed Post by cosbycarl on Jan 8th, 2009, 10:44pm I found the reg where it states that a flex cable has to be visible along its length in case of mechanical damage, its reg 413.3.4 or page 57. Thing is though, its only if the circuit or install has the protective measure of electrical separation, so doesnt apply under normal conditions, but would if there was a shaver socket installed i suppose (or other methods of electrical separation) |
|
Ask The Trades » Powered by YaBB 2.3! YaBB © 2000-2008. All Rights Reserved. |
