MF style push fit connectors

[Darkwood]

Had the local wholesalers premoting his varied range of Wago push fit type connection blocks when he showed me one that had me thinking that to use it correctly you would contravene the regs... your thoughts...

What he showed me was a connector for downlight where its got entry points on one side for solid or normal stranded cables and then on the other side of same connector it has a entry designed to clamp fine wire like flexes etc which you normally shouldn't use with these type of connectors ...all sounds super duper BUT!!! heres the thing the reg's does state that fine wire cables should always be crimped with the appropriate crimp or ferel before termination thus the design features of said connector seem to be made to fulfil a issue that shouldn't exist if the electrician was doing his job correctly in the first place by crimping the cable.

 

[ayjay]

imo they used to be used in panel /control 24v wiring to the relay supplys
to use these on 240 volt high current is no good
its just a spring loaded junction
i dare say someone on this now silent forum might post

 

[LineProducts]

Had the local wholesalers premoting his varied range of Wago push fit type connection blocks when he showed me one that had me thinking that to use it correctly you would contravene the regs... your thoughts...

What he showed me was a connector for downlight where its got entry points on one side for solid or normal stranded cables and then on the other side of same connector it has a entry designed to clamp fine wire like flexes etc which you normally shouldn't use with these type of connectors ...all sounds super duper BUT!!! heres the thing the reg's does state that fine wire cables should always be crimped with the appropriate crimp or ferel before termination thus the design features of said connector seem to be made to fulfil a issue that shouldn't exist if the electrician was doing his job correctly in the first place by crimping the cable.

Which reg are you referring to?

 

[Darkwood]

Ferels are for use even at 230v i use them all the time in contrl panels on both selv and Lv 230v as that is the requirement on any multi-stranded cable even if your extending a pendant drop flex you are required to crimp the cores, all manufacturers of flexed products have to abide too as you'll see in any pre-wired fittings where fine strand cables or flexes are used.

 

[LineProducts]

Ferels are for use even at 230v i use them all the time in contrl panels on both selv and Lv 230v as that is the requirement on any multi-stranded cable even if your extending a pendant drop flex you are required to crimp the cores, all manufacturers of flexed products have to abide too as you'll see in any pre-wired fittings where fine strand cables or flexes are used.

I am not aware of any BS7671 reg that requires this. Please give details.

 

[Darkwood]

Which reg are you referring to?

Just re-read reg 526.8.1 and it is a bit ambiguous but as i read it you must ensure that the cable (fine or very fine wire) dosn't seperate the individual cores or spread them ive yet to see any kind of connector that ensure this cant happen either when offering the cable into the terminal or in its clamping method, in control panels all fine wire cables are ferel or crimped before terminating.

If the cable cores are free to move about while pushing them into the connector then they become prone to at least a few bending back or spreading out and IMHO twisting the cores as im sure some will suggest shouldn't be the solution as this dosn't always stop itbut instead a correct ferel crimped.....
I may be keen on this because i do control panels and its a given must they are crimped although its stepping away from the BS7671... with regards to panel wiring i understand it that 526.8 was introduced to cover the crossover

 

[LineProducts]

526.9.1 - ...suitable connectors shall be used or ...ends treated.
The lighting connectors (mentioned above) and the lever connectors that we do are "suitable" for fine stranded - BS60998.
(but I do respect your approach i.e. if in doubt err on the side of safety!)

We do a spring cage DIN rail connectgor that is suitable for fine stranded without preperation.
http://lineproducts.co.uk/forumshop/index.php?main_page=index&cPath=11_16

 

[Darkwood]

I relish your input been you niche and area, can i ask what is to stop cable spread or loose strands in your fine wire freindly connectors as i can see the regulation as it is but been brought up always putting ferels on as you cant guarantee the flimsy fine cores wont stay together while pushing them into the connector without them been fereled or tinned in some form.
Next question if they are ferel crimped does this still mean the connecter is suitable as it no longer acts like a fine wire but is like a solid core.

 

[LineProducts]

Springs are ok for both solid core (and where design for) fine stranded.

If you think about the problem in a screw connector, the screw itself can seperate the strands pushing through the middle of even through rotation push strands to the side - an obvious problem.

However, the cage, surrounds all the cores before tightening and then a horizontal edge of the spring pushes the cable down onto the busbar. The resulting cross section (under pressure) tends towards a rectangluar shape. so even if there is total spread of the strands a decent connection will still result.

The product standard states: ... suitable without additional preparation of the cores, OTHER THAN TWISTING WITH FINGERS. With fine stranded twisting does make the job easier and improve the final result.

 

[Darkwood]

I jump onto your link and yes im fine with your explan' now and gives me other options, it a matter of technology and product design change been a little further ahead than i was in this case, but appreciate your help and input, although you do a dinrail version i will still always ferel as it also stop the number kits dropping off too if you are ever doing maintainance or fault finding, but ill look into getting a catalogue from you through your website. Cheers