Armoured cable - radius of bends?

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robgul

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I'm going to run a 2.5 T&E Armoured cable from the house about 15 metres to an outbuilding, fixed to a wall. That's straightforward - my question is how tight can I make the bends in the cable where it turns corners?

The turns, if I can do them are 90 degrees - it's how tight I can make the radius that's the issue - connections will, of course, be "to regs" - I don't want to have to use any connection boxes to turn the corners.
 

Lorenzl

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6 - 8 times the cable diameter depending on the exact style of cable. You could find the exact information if you know the manufacturer as they should publish it.

Vertical corners will look OK but horizontal ones won't unless you cut a slot in the corner of the wall ;)
 

robgul

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You might get a tighter bend radii with xple cable.

I think that's XLPE ? - but doesn't appear to be armoured? - as it's going low down on the wall along the back of flower beds I'd be concerned about my wife hitting it with loppers/secateurs/strimmer etc.
 

Spectric

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First question is what is the cable, I assume it is armoured and not twin & earth so how many cores as this will impact the max radius ? When running armoured cables round corners they should not be forced and just allow them to decide. I assume that the outbuilding does not have any extranous conductive parts such as a metal frame or cladding otherwise some changes will be needed and how was the 2.5mm decided upon?
 

robgul

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Just a thought. Could you bury it to create a greater loop whilst going round the exterior corner?

I've re-thought the way it's going to be and it will now climb the wall and then turn across a "bridge" to get to the house (i.e. there'll be an arch over the passage between the wall and the house.) - and the corner that it was going to go round has concrete on the ground!
 

robgul

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First question is what is the cable, I assume it is armoured and not twin & earth so how many cores as this will impact the max radius ? When running armoured cables round corners they should not be forced and just allow them to decide. I assume that the outbuilding does not have any extranous conductive parts such as a metal frame or cladding otherwise some changes will be needed and how was the 2.5mm decided upon?

It's 6943X - and as the OP says 2.5 T&E Armoured - as recommended by a qualified electrician who has also advised on the connections/outlet. The supply is to run some low-ish powered garden machinery and possibly some lights on the odd occasion - and the building is wooden.
 

pe2dave

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I've re-thought the way it's going to be and it will now climb the wall and then turn across a "bridge" to get to the house (i.e. there'll be an arch over the passage between the wall and the house.) - and the corner that it was going to go round has concrete on the ground!
So where are your 'right angles' now? ground going up the wall, external wall corner? Not clear?
 

morqthana

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I'm going to run a 2.5 T&E Armoured cable from the house about 15 metres to an outbuilding, fixed to a wall. That's straightforward - my question is how tight can I make the bends in the cable where it turns corners?
Nowhere near tight enough.

If you can accomodate a change in height, what you can do is to sweep the cable up (or down) as it approaches the corner, so it's vertical when it gets there, ease it around the corner as it goes up (or down) then turn it horizontal.

The turns, if I can do them are 90 degrees - it's how tight I can make the radius that's the issue - connections will, of course, be "to regs" - I don't want to have to use any connection boxes to turn the corners.
No regs against junction boxes.

What will the cable supply?
Where does it originate?
Where is the RCD protection?
Is it a new circuit?
What will the glands be installed in?
Did you buy extra cable to practice terminating it?
 

robgul

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Nowhere near tight enough.

If you can accomodate a change in height, what you can do is to sweep the cable up (or down) as it approaches the corner, so it's vertical when it gets there, ease it around the corner as it goes up (or down) then turn it horizontal.


No regs against junction boxes.

What will the cable supply?
Where does it originate?
Where is the RCD protection?
Is it a new circuit?
What will the glands be installed in?
Did you buy extra cable to practice terminating it?

New plan has gentle curves which will work with the cable - and YES/OK/COMPLIES (all advised by a qualified electrician) - to all your comments, or already answered

I've done all this before but a while ago.
 

pe2dave

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Daft one @robgul - but seems to apply. Electricity doesn't like going round corners!
Seems you've got it though.
Stressed cable, outside, you can guess the consequences over a long period.
 

Spectric

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6943X is 2.5mm three cored armoured, it is not twin and earth. 6943X2.5MM BASEC Approved 6943X Black 3 Core Steel Wire Armoured Cable 2.5mm (priced per metre) - Shop4 Electrical

Anyone in the game would know that, so is this qualified electrician called Joe by any chance.

If you measure the OD it will be around 15mm, the minimum bend radius will be 90mm, it will probably not notice and is not really worth the worry but if you want to hide the corners then garden ordaments or flower baskets. Start running 185mm 4 core and then bend radius can be a real headache!
 

robgul

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6943X is 2.5mm three cored armoured, it is not twin and earth. 6943X2.5MM BASEC Approved 6943X Black 3 Core Steel Wire Armoured Cable 2.5mm (priced per metre) - Shop4 Electrical

Anyone in the game would know that, so is this qualified electrician called Joe by any chance.

If you measure the OD it will be around 15mm, the minimum bend radius will be 90mm, it will probably not notice and is not really worth the worry but if you want to hide the corners then garden ordaments or flower baskets. Start running 185mm 4 core and then bend radius can be a real headache!

OK - my terminology for the 3 core that is to be used as T&E - he just gave me the number of the cable.

I'm done with this thread - cable ordered, I should get the job finished during the coming week . . . water is involved too!!
 

mikej460

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I solved this by sweeping into the workshop then swept gently back to the inside wall. The resulting small bulge is hidden behind a cupboard.
 

morqthana

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6943X is 2.5mm three cored armoured, it is not twin and earth. 6943X2.5MM BASEC Approved 6943X Black 3 Core Steel Wire Armoured Cable 2.5mm (priced per metre) - Shop4 Electrical

Anyone in the game would know that, so is this qualified electrician called Joe by any chance.
Oh come on - he said it was armoured, and he said it was 6943X. So he said it was "T&E" armoured instead of "3-core" armoured.

Wow.

I could point out that here:
you use the terms "ring main" (no, it's "ring final") and "live" (no, it's "line"), but I won't, nor will I ask if your name is Joe.
 

Stevekane

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This is all great fun and I cannot resist jumping in. First a sensible bit,,,are you talking about 3 core plus earth or as you said “twin and earth”? The reason I ask is that if you go for the “4 core stuff” you can for instance use that 4th wire to switch on say an outside light on the shed from inside the house which can be very handy,,now a question, why cant you just put your foot on a bit of armoured cable and bend it as tight as you can, I wouldnt have thought that the plastic insulation would be damaged and in any case your constrained in how tight you would get it by the twisted armour and outer caseing?
Steve.
 
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