Acute Internal Conduit Bend

[Sidewinder]

Just curious.

I lost out on a job a few months ago, that has just popped into my mind whilst I was planning another!

Listed Building, Church.

I quoted fitting black externally graded "flex" to go around the route required to the external EM lights, of a suitable rating for the self contained "NM3" emergencies on the external escape route.

I lost out, unsurprisingly TBH to another, not too worried as it was a favour for a friend anyway and not our target market.

However, the "contractor" that got the job, used black PVC conduit.

Now in one corner it was an acute corner of about 30 degrees, being generous.

Now the "contractor" bent the conduit to 30 degrees internal angle, thus basically folding it flat.

I have NOT complained to the "person in charge" yet, as IMHO it would be seen as sour grapes.

Now I would not have done this, I would have used a "trouser" box and a smaller set in one leg, or a 90 box with a set further out of the corner.

What would the rest of you have done, remembering that you are working in 20mm black conduit.

Not quite as difficult and controversial as my Y/D motor thread, and not looking for a definitive answer, as, it is doubtful it will be changed now, but, the conduit is pretty flat in the corner!"

 

[Zeespark]

Is it an 'internal' or 'external' 30 degree bend Sidey?

Andy Guinness

 

[steptoe]

never bend conduit tighter than 75

and only as a one off if must be,

personally, I dont like it, but I have done it on occasion,

HTF did he get the cables pulled round is my question?????!!!!!!!!

oh,

solution,

end box and rear entry for tight ones,

ooohhhh eeeerrrr missus,  :|

ah, just worked out your  'trouser box'  :slap

yes, a  'U box' would do too, if you can put it in the plane,

 

[Sidewinder]

The angle is internal as in the internal angle of a capital A IYKWIM.

Steps, I thought you would have known what a trouser box was, but, I must admit that now that is was not the best description, as it could be understood as a 3 entry box with one, one side and two the other 180 deg away, not sure, so perhaps what you describe as an end box would be better where you just have two entries in parallel "one side".

Maybe web links to the boxes are needed?

 

[steptoe]

2 entries parallel on one side is what I call a U box,

yes, if you can put it 'flat' , then perfectly good, and perhaps better than a rear entry,

all depending on the actual location, as ever,

but anything deffo better than a bend that F-ing tight,  :shakehead

U box  , I think this is your trouser box,,,?

end box

 

[Zeespark]

Sidewinder, could you not do a 2 part bend incorporating a through box with some sort of batten fixed behind it for support? :innocent :run

Andy Guinness

 

[Sidewinder]

Yes, I agree perhaps a U box would be a better description.

I could not believe that it had been bent to an internal angle of around 30 deg. the conduit was well flat!

Not sure how the wiring was dragged around that, plus I'm not sure what wiring material it is, and not sure if I ever will know now as I lost the job.

Mind, the client got an insurance inspection after my EICR & remedial works and gor 3  queries, which were down as needing more investigation, on my EICR as not really appropriate, to the EICR.

They got lightning protection, emergency lighting & fire alarms, the whole of the BS7671 specific stuff was all OK'd!

Dunno Andy, it was not my job, I lost it on price, the acute conduit bend was by the winning contractor.

Basically as it was external on a listed building and the route, I wanted to use UV proof flex or FP200 type cable,

The height was enough to allow "bare" flex.

The conduit install is rubbish TBH.

 

[Zeespark]

OK, I was simply looking at it from the description that you gave it from the letter A, I apologise if I went off on a tangent.

Andy Guinness

 

[Sidewinder]

No need to apologise mate, it is easy to misunderstand the written word on here.

 

[steptoe]

Yes, I agree perhaps a U box would be a better description.

I could not believe that it had been bent to an internal angle of around 30 deg. the conduit was well flat!

Not sure how the wiring was dragged around that, plus I'm not sure what wiring material it is, and not sure if I ever will know now as I lost the job.

Mind, the client got an insurance inspection after my EICR & remedial works and gor 3  queries, which were down as needing more investigation, on my EICR as not really appropriate, to the EICR.

They got lightning protection, emergency lighting & fire alarms, the whole of the BS7671 specific stuff was all OK'd!

Dunno Andy, it was not my job, I lost it on price, the acute conduit bend was by the winning contractor.

Basically as it was external on a listed building and the route, I wanted to use UV proof flex or FP200 type cable,

The height was enough to allow "bare" flex.

The conduit install is rubbish TBH.

OK,

so I dont really do anything on listed buildings,

and anything Ive ever done in the past has all been spec'd,

but, I wouldnt have thought you could just run conduit around the outside of a listed building,,,,,,,

can you.?

:C

 

[Zeespark]

It would be upto the Conservation Department at the local council I think Steps.

Andy Guinness

 

[Andy™]

if you can change the height then you could do 2x 90 bends,

 

[binky]

the only way you could do an acute bend like the one desribed, and maintain a space for cable would be to cut away the internal side of the conduit leaving a connecting strip of material - think mitre join type of thing.

Listed buildings vary enormously on restrictions, sometimes they won't even allow drilling holes for fixings, despite years of previous such works. Main thing is to try and hide works, minimising visual impact.

 

[SLIPSHOD & SLAPDASH]

I use black FP200 (well actually its Doncaster fire rated as its the only black i know i can pick up locally) on external jobs. Normally use black Wiska boxes also as they look neater than a H or Y box. We also years ago had a knuckle bender for 20mm conduit, but had to get authorisation to use it from the office

 

[binky]

don't think I've ever seen a knuckle bender. Plenty of scraped and bleeding ones...haven't had a good day without at least one :^O

 

[Evans Electric]

In the world of conduit it is deemed a capital offence  to pull a bend more than 90 deg.  

For the sake of argument you could tube up to a through box ,   then for the acute internal angle , make a right angle bend up or down , tucked into the corner , say 9" long  then a second right angle flat on the other wall so you come away at a different level but its wireable  .   

Difficult to describe , I'll draw a pic if necesarry .     

The obvious way would be Sidey's plan of black flex /  FP .

 

[Steve3948]

In the world of conduit it is deemed a capital offence  to pull a bend more than 90 deg.  

For the sake of argument you could tube up to a through box ,   then for the acute internal angle , make a right angle bend up or down , tucked into the corner , say 9" long  then a second right angle flat on the other wall so you come away at a different level but its wireable  .   

Difficult to describe , I'll draw a pic if necesarry .     

The obvious way would be Sidey's plan of black flex /  FP .

What about when making a sledge, or ladder hooks  :innocent

 

[Evans Electric]

Sorry about childish drawing but it makes my point .

 

[Sidewinder]

Thanks for the suggestions guys, the bend looked a bit "flat", but then the installer was cheaper than me you see, so cheaper is always better!

It was not the sort of thing I would have done, and it is on the borders of the sort of work I take on anyway.

By all means keep the discussions / ideas coming if you like.

I like that idea Deke!

I doubt that I will get the option to re-do the job, but IIRC that would have been an option, and something I had planned on with the FP TBH.

Oh, and Childish drawing, you are kidding, that is excellent in comparison to my sketches!!!

 

[Andy™]

*cough* post 12 *cough*