SWA bend radius

[dobby1]

I will be running some 16mm^2 3-core SWA. Most of the run has bends which are within an acceptable min bend radius. However, the final end of the run goes 2.5m up an exterior wall, w/ a sharp 90 degree bend through masonry and some 1st floor joists to the CU.
The problem is I don't have much room to get a decent radius on it since the run will be through the joists and so there is a good chance the cable will kink.

I am planning on terminating to a junction box, and then run some T&E up to the CU, but I'm not keen on making breaks in a run if it can be avoided. It'll introduce another point of failure, and who wants to be diagnosing electrical faults 2.5m up on a ladder ?!

Does anyone have any suggestions/work arounds? or am I condemned to terminating outside?

 

[flameport]

Masonry can be dressed to have a curve into the wall, rather than just drilling a hole straight through and bending the cable.
If it's render/cement or whatever, it can be filled later to cover the curved section.
If bricks, then remove a whole brick, drill through where the brick has been removed, dress the brick below into a curve to hold the cable, install cable and replace the brick removed previously.

 

[flameport]

Example:

Black cable.
Brick A is removed completely to enable the hole to be drilled on the inner leaf.
Brick B has the yellow part removed.
Cable is installed
Brick A is replaced, the back may need to be cut to accommodate the cable.

 

[mwatsonxx]

I am planning on terminating to a junction box, and then run some T&E up to the CU

That's the way a proper spark would do it.

Ignore flameproof he is very inexperienced spark and a dodgy bricklayer that guesses at solutions.

Also there is nothing wrong with creating a loop in the cable so it can enter the wall at 90 degrees.

 

[Iggifer]

That's the way a proper spark would do it.

Ignore flameproof he is very inexperienced spark and a dodgy bricklayer that guesses at solutions.

Also there is nothing wrong with creating a loop in the cable so it can enter the wall at 90 degrees.

I think what you meant to say, before your unfounded character assassination was “that’s the way many sparks would do it, because it’s easier”.

In no way, shape or form is introducing not only extra connections but the potential for water to enter the junction box, however unlikely, the way a ‘proper spark would do it’

There’s nothing wrong with creating a loop so it enters the wall at 90°?! Are you mad? That would look awful. For a swooping bend on a 16mm 3C SWA you’d have birds landing on it!

Not only that, but having jointed it onto 16mm T&E you are then going to most possibly have to run a separate CPC with the T&E as the SWA is bound to be feeding a submain. Whether that submain should be TT is another question, but with it being 3C, it would appear the main earth is being exported

 

[chivers67]

Flameport has recieved enough Thanks on here to be treated with a bit more respect! I think cutting the brick out is the best option especially given it will be a bit of a nightmare to run the SWA without being able to feed the cable though a hole.

 

[EFLImpudence]

Plus this excellent website:

https://www.flameport.com/documentation/index.cs4

 

[Adam_151]

Its 16mm² 3core, its not that big, drill the hole with a bit of a slope on it so the bend can be a little less than 90 and theres no water ingress. Slightly radious the corner of th brick with a scutch, pre-form the bend in your hands before pushing the cable into place

 

[Simon35]

Its 16mm² 3core, its not that big, drill the hole with a bit of a slope on it so the bend can be a little less than 90 and theres no water ingress. Slightly radious the corner of th brick with a scutch, pre-form the bend in your hands before pushing the cable into place

16mm 3 core swa has a 130mm-ish bending radius. Not sure that's going neatly round a slightly radiussed brick tbh.

 

[333rocky333]

That's the way a proper spark would do it.
.

Not sure they would.

 

[ban-all-sheds]

Do remember the 2-plane S-bend as a way to cope with bending radii.

 

[Simon35]

Do remember the 2-plane S-bend as a way to cope with bending radii.

Just remind me again, what's that look like?

 

[John D v2.0]

Not sure bending it in 2 planes would help as the bricks are a flat 2d surface. If it had to bend directly into the joists and the holes had to only be in the neutral zone of the joists then it would be essential to do that, but by the time it gets to the joists it will have fully bent.

 

[ban-all-sheds]

Just remind me again, what's that look like?

First, a disclaimer - I didn't try to visualise the route the OP's cable has to take.

And now I'm going to ask you to visualise from a written description. I'll try to get around to doing a sketch later.

Imagine you have a cable running horizontally, and you need to go round a corner (internal or external). You bend the cable through 90° on the surface of the wall such that it is running vertically on, or in, the corner (easier to picture it on an internal one). Then you bend it so that it starts running horizontally on the other wall.

 

[JohnW2]

Imagine you have a cable running horizontally, and you need to go round a corner (internal or external). You bend the cable through 90° on the surface of the wall such that it is running vertically on, or in, the corner (easier to picture it on an internal one). Then you bend it so that it starts running horizontally on the other wall.

I understand how that works 'on' a wall, but is it going to be possible to do the same when 'going through' a wall without have to remove two or more bricks?

Kind Regards, John