SWA cable Terminating or not??

[Tinman]

Had a discussion with my electrician today about upgrading the SWA mains cable fed from my house to my garage as im looking to use the garage for some woodworking machines, eg table saw, planer as well as some sockets and lights.
Sparky has informed me that there is currently a 3 core 6mm SWA feeding the garage and for what im looking to add It would be best to change this out to a 3 core 16mm for what i was looking to use with some future proofing if i decided i wanted to add some more things in the future.
I wish to point out that the consumer unit within the property is plastic and not metal

The purpose of this post is that he has told me that due to the size of the proposed new cable that it would be best terminated into a box on outside wall of property located directly behind the consumer unit and then brought into the property in a cable which is more easily positioned into the plastic consumer unit. The garage side he said he would drill the concrete floor and take the SWA straight through up to the Consumer unit in there so its only at the house side I have a concern.
This is not how the original 6mm cable has been done as it has been fed all the way through the external wall into the consumer unit.
I was just wondering if he is suggesting an easy install for himself by suggesting this way or if he is making complete sense given that this is a much heavier duty cable and harder to bend.
He did also say that by doing it this way that both ends of the SWA would then be connected to earth instead of just one at the garage side.
I would have thought that the less connections there are the better and also less chance of anything going wrong with connections in the future.

Happy to hear what some other guys thoughts on this are as this is only the first guy I have spoken with so far about it.

Cheers

Tinman

 

[westward10]

What make is your consumer unit as you will be restricted to the maximum size of mcb you can fit, 16.0 maybe overkill but would need more information to confirm that.

 

[SJD]

I wish to point out that the consumer unit within the property is plastic and not metal

If the consumer unit is plastic, then if terminating the SWA inside, perhaps it would be into a metal adaptable box adjacent to the consumer unit, assuming it is to be connected to an MCB in the consumer unit.

He did also say that by doing it this way that both ends of the SWA would then be connected to earth instead of just one at the garage side.

I don't see why the method of terminating the SWA at the house would restrict whether that end is earthed or not. Whether there is a box outside, or a box inside, the amour should be glanded, and an earth connection can be made, e.g. via a piranha nut, earth bar or banjo.

Unless the electrician was thinking of just snipping the armour off and bringing only the inner SWA cores into the plastic consumer unit. In which case you probably want to find someone else who knows how to terminate SWA properly.

 

[Tinman]

What make is your consumer unit as you will be restricted to the maximum size of mcb you can fit, 16.0 maybe overkill but would need more information to confirm that.

The consumer unit is legrand and when the sparky measured out distance he said I would require 18m of armoured cable to go from house to garage.
He did say that I could probably go with a slightly smaller cable but the 16mm would be sufficient if I added more things in the future and it would be more cost effective to put in a bigger cable now than having to possibly redo the job again in the future.

 

[Tinman]

If the consumer unit is plastic, then if terminating the SWA inside, perhaps it would be into a metal adaptable box adjacent to the consumer unit, assuming it is to be connected to an MCB in the consumer unit.

I don't see why the method of terminating the SWA at the house would restrict whether that end is earthed or not. Whether there is a box outside, or a box inside, the amour should be glanded, and an earth connection can be made, e.g. via a piranha nut, earth bar or banjo.

Unless the electrician was thinking of just snipping the armour off and bringing only the inner SWA cores into the plastic consumer unit. In which case you probably want to find someone else who knows how to terminate SWA properly.

The original installation which is done in 6mm is glanded at garage consumer unit and the end coming from house has the swa going through external wall straight into the back of consumer unit and therefore no gland on armour but has one of its 3 cores connected to the earth bar.
Sparky had said that if he was to install a metal gland box internally then it would be a case of having to open up the internal wall for access which I didn't really want to do hence why he suggested terminating outside the house with a suitable box.

So getting back to my main questions:

(1) Is it OK to have the cable terminated outside the house like he suggested?

(2) Could it be taken into consumer unit with armour still on and obviously no gland at house side but glanded at garage side just like the existing cable now?

 

[westward10]

It should be glanded both ends.

 

[SJD]

Sparky had said that if he was to install a metal gland box internally then it would be a case of having to open up the internal wall for access which I didn't really want to do hence why he suggested terminating outside the house with a suitable box.

Perhaps post a photo showing the consumer unit and the area around it. Typically an internal box to terminate the SWA would sit either immediately next to the consumer unit, but it doesn't have to.

Despite seeing it often, it is not acceptable to just poke the end of the SWA into the consumer unit.

 

[Tinman]

Ok so I had another spark out today to have a look at my proposed work and he is offering me this solution.

To remove existing 6mm2 swa cable feeding garage.
Install new 16mm2 swa 3 core with CW glands both ends and connected via pirhana nuts.
Garage side terminated directly Into existing metal consumer withing the garage.
House side terminated into IP66 plastic box on outside of house with inner cores and insulation passing through newly installed plastic Conduit directly into rear of existing plastic consumer unit.
Additional single core fly leads to main earth terminals.
Change out of existing mcb and carry out test work.

He said that by using a 16mm2 cable it would be best terminating the swa outside as the bending radius for this cable would promote difficulties trying to take it inside.

Sounds like he knew much more than previous guy and did even comment about existing swa only being glanded at the garage side with house side just being poked through wall with tape around end of outer armour.

Other than just waiting for a cost to come back from him for all this. Does this sound like a correct proposed installation?

Tinman

 

[westward10]

Sounds more positive.