Maintenance free JBs ( So called)

[Evans Electric]

There was a time when we avoided doing a hidden JB   .  Then the maintenance  free jobbies  appeared  and its was  ...Yeahh  stick 'em anywhere !!   

They work basically on the principle of a bent bit of metal holding a cable in place ...........wondering if a heating pipe was installed by one , the tension would be altered over time and a loose connection develop .      

The old fashioned screw down  JB  would be unaffected . 

Just saying .

 

[Murdoch]

There was a time when we avoided doing a hidden JB   .  Then the maintenance  free jobbies  appeared  and its was  ...Yeahh  stick 'em anywhere !!   

Sorry mate but I disagree. I only use them as a "last resort" practice. 

All connections at switches, sockets and accessories for me.

 

[Evans Electric]

I know that  and agree, I do the same ,    but we were given leave to seal in maintenance free JBs  because they didn't have screws  and they will never go wrong .  

 

[binky]

everything fails at some point, but the bent bit of metal is sprung loaded, so in theory maintains consistent contact with cable ad infinitum, until a Chinese copy emerges....

 

[Tony S]

First time I came across this type of connector was 20 years ago on Telemecanique switchgear. OK the control current wasn’t high, the temperature in the breaker coil section was. The heat hadn’t affected them.

My only gripe was I had to do a lot of modifications, getting connections undone wasn’t easy.

 

[Jono Pashley]

There was a time when we avoided doing a hidden JB   .  Then the maintenance  free jobbies  appeared  and its was  ...Yeahh  stick 'em anywhere !!   

They work basically on the principle of a bent bit of metal holding a cable in place ...........wondering if a heating pipe was installed by one , the tension would be altered over time and a loose connection develop .      

The old fashioned screw down  JB  would be unaffected . 

Just saying .

Really is that why every floor i lift has them stuffed under it?

 

[ProDave]

When I used to do industrial machinery, Wago's were frowned upon and considered the work of the devil, and we were virtually banned from using them.  I am talking the Wago DIN rail terminals here, we had to use proper screw down ones.

 

[Evans Electric]

Wago's were frowned upon and considered the work of the devil, a

Was that possibly down to Mr Stickin Themud  not wanting to adopt or try a new idea.  ?   He,s in charge and thats it !!! 

I've had many cases of that happening ,  one was from my old boss  after metrication .  We found ourselves wiring conduit with 2.5mm    6491X    single Solid core ,   the Devil's work .  We went from 7/.029  ( So  a flexible cable with 7 strands making up the core)  to , stiff, solid ,  2.5 mm sq  core )   .   Ring main in conduit was awful , 6 of these cables fighting you  all the way .    Gaffer  said the stranded was too expensive  when complaints rained down  on him .  Then I asked at the wholesaler what the difference was ,   none ,  its just your boss who buys this stuff , no one else will give it house room . 

Really is that why every floor i lift has them stuffed under it?

It was accepted practice I suppose ,  its accessible if you lift a board .

 

[ProDave]

That's a bit like the folk who insist on wiring lighting in 1.5 t&e.  Great "fun" with some light fittings. And some people you just can't tell them that 1mm is fine.

 

[Evans Electric]

I've had that argument for years  .  Some guys say it is " rubbish "     "Never use it "   with no actual reason .   With   3 & 4 bed houses  all the upstairs , say ,  lights pull , say 2A , cable rated at 11A   I think  last time I looked ,  even buried in insulation .  

My partner used to wire LED downlights  in 1.5  ,  difficult to connect , total  watts  in a kitchen , say ,  45W . .   unnecessary  , waste of resources ,    Load of 1A   with a cable rated at   16A    or whatever.    

 

[binky]

I had a spell of using 1.5mm for lighting when downlighters were halogen, but have since gone back to 1mm, as stated above the fittings are just f-ing useless for 1.5mm

 

[roys]

Just rewired my own house, needless to say both lighting circuits wired in 1mm.

 

[kerching]

We found ourselves wiring conduit with 2.5mm    6491X    single Solid core ,   the Devil's work .  We went from 7/.029  ( So  a flexible cable with 7 strands making up the core)  to , stiff, solid ,  2.5 mm sq  

Wasn't it called just 6491.       Then the stranded was called. 6491x7.( the 7  representing the 7 strands)... then they  lost the 7?

i may well be wrong....as usual

 

[Evans Electric]

Its a long time ago now  I'm afraid  .  Yes It may have been .   I was thinking back to the Imperial sizes  where the stands were given  as , say,   1/.044   ( 1 strand of .044)  , 3/.029  (  3 strands of .029  )      3/.036   then 7/.029  ( 7 strands ) etc    They went up like  7/.044  ....7/.052  ... 7/.064    then did they jump to 19 /.052   sort of ?  

Metric is actually  simpler .       Yes I think the metric  started with  6491   X 7     then  6491X   STR   possibly  then just   2.5   6491X     or  6242Y  .  

On cranes we used a super flexible version because it  moved & juddered etc      ...forgotten what that was called  but you could loads of 'em in conduit  without soap.   :C   

 

[Tony S]

On cranes we used a super flexible version because it  moved & juddered etc      ...forgotten what that was called  but you could loads of 'em in conduit  without soap.   :C   

If they are what I’m thinking of, they had french chalk on them to stop them sticking together on the reel.

Cables with tarred hessian serving had whitewash on them, after making them off you could have passed an audition for the black & white minstrels.