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Does anyone have any thoughts on the best way to terminate an SWA into the new style flush CUs such as Hager's, BG's etc.? I ask as all seem to either employ oval or square knockouts, which is great for the surface boards when using truncking etc. but no great if you are trying to comply with Reg 522.6.204 and 522.6.204 where your tails would effectively be inside a wall / burried less than 50mm from the surface.

So far the best but not really ideal solution I have come with for top or bottom entry (to overcome what seems like a design flaw to myself) is that you would need to terminate the armoured cable into something like a galvanised adaptable box that you mount hard up aginst the bottom of the CU oval / sqaure entry to get the SWAs cores safely into the CU (using gromet / gromet strip on all edges etc.). I know the Hager board has a round KO on the left and right hand side but this would causes an issue in most cases in terms of space to allow for the cable bend. You then have issues with your cables falling outside of prescribed zones as you are likely to want to route them verticle up or down in the wall once out of the CU.

So intrested to know what others think would be a good solution or thoughts from anyone who has had to fit any of these newer flush units.
 
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  • #3
I use a holesaw.
I also thought of that but due to the position of the KOs and the frame that then sits indside the CU to allow for different wall depths there doesn't seem like there is enough material left to not weaken the CUs integrity too much. I have uploaded the Hager flush PDF for refereance as just one example.

Also for anyone with too much time on their hands ;) here is the Hager video on their flush CUs


Looking at their video unless there is a 30ma RCD upstream then the example installation is no compliant with the regs. If there is a 30ma RCD upstream then there is no way of ensuring selectivity if the board is full of 30ma RCBOs
 

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Andy78

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Why not use metal protection for the tails so they comply with 522.6.204 ?
A buried gland is not accessible for inspection.
 
D

Deleted member 26818

A lot of copper showing there on the factory fitted links.
 

Andy78

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A lot of copper showing there on the factory fitted links.
There always are unfortunately. Comes from the insulation being a sleeving rather than being bonded to the conductor more tightly like in tails cables.
 
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OP Where is the MET in this scenario?
So I am looking at this as being the MET is located else where such as a meter cab or under the stairs with the CU located some distance away (over 3m cable required) feed from a switch fuse (e.g. Wylex or Lewden).
 
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  • #11
There always are unfortunately. Comes from the insulation being a sleeving rather than being bonded to the conductor more tightly like in tails cables.
I take your point about the gland but was considering whether that was the lesser of the two evils in terms of providing suitable mechanical protection. With an SWA where the armour is not being relied on for the earthing arrangements (so 3 core SWA single phase) and the other end is earthed and inspectable. Is that worse that say using metal protection such as trunking (conduit would require adaptable box with no means of verifying that the consuit was earthed once all sealed up) where the earthing arrangments of the trunking could not be verified either once burried.
 

Andy78

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I take your point about the gland but was considering whether that was the lesser of the two evils in terms of providing suitable mechanical protection. With an SWA where the armour is not being relied on for the earthing arrangements (so 3 core SWA single phase) and the other end is earthed and inspectable. Is that worse that say using metal protection such as trunking (conduit would require adaptable box with no means of verifying that the consuit was earthed once all sealed up) where the earthing arrangments of the trunking could not be verified either once burried.
I was meaning the use of steel protection for the tails that would protect against nails and screws which does not require earthing.

You could just do what all the other new build lads do and just stuff the swa through the back of the board with no gland or anything. Seems to be the current standard.
 

Midwest

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Why not use metal protection for the tails so they comply with 522.6.204 ?
A buried gland is not accessible for inspection.
In this instance, would the gland not be identifiable (from inside the CU), therefore easily located and could be inspected with the removal of a piece of plasterboard? Its not as if the joint is being buried in the ground, aka reg 526.3.
 

Andy78

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In this instance, would the gland not be identifiable (from inside the CU), therefore easily located and could be inspected with the removal of a piece of plasterboard? Its not as if the joint is being buried in the ground, aka reg 526.3.
It's not usual to have to dismantle the fabric of the building during an inspection.
 
As long as one gland is readily accessible at the source end and the armour is not relied upon for the cpc it does not really matter if one is no longer accessible as it serves one purpose, connection of the cable. Verifying its integrity down the line is not an issue.
 
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