UK Class II enclosure + gland recommendation for divorcing SWA armour at TT outbuilding/shed?

[rossinator]

As the title says, I am looking for a recommendation for an enclosure and gland arrangement to electrically isolate or divorce the earth/armouring of a two core SWA supplying an outbuilding/shed. The supply to the property is overhead TT, so DNO provide phase and neutral only, a sub 20 ohm rod provides the main earth for the house DB. The DB in the wooden outbuilding/shed (which contains no extraneous metal or services) is supplied from the main house DB by a 2 core SWA. The shed DB which is two way with RCD main switch is currently using the main house rod as it's earth, utilising the armour of the SWA as it's cpc. The plan is to give the shed it's own low ohm rod and divorce the earth from the house at the outbuilding end, whilst leaving the armour for the SWA connected to earth at the house end. The following webpage and image sums up the situation well. The recommendation I am looking for is the part of the image below that is labelled "All insulated Class II enclosure". I've read that some people just bung the SWA in a stuffing gland in a wiska. I asked Wiska to recommend something and the said they couldn't offer a suitable Class II product and suggested Pratley. So here I am asking for recomendations for a strong reliable product / solution? The shed DB is metal. Many thanks.

Voltimum - armoured cable supplies to outbuildings

 

[brianmoooore]

Both are quite capable on the current carrying capacity front, but maybe needed for voltage drop? What is the approximate cable route distance from house to outbuilding

Only about 10m (see post #10)

 

[pc1966]

Only about 10m (see post #10)

Ah - missed that.

Still buildings 10m apart might not reflect cable length!

 

[OldSparks]

Hi All
DO NOT RELY ON THE SWA WIRE SHEATHING FOR EARTHING TO AN OUTBUILDING !!!!
Disconnect one end of the sheathing and use it only as an earth protection for the feed cable. Then provide a dedicated earthing method for the out building.
It is unlikely the steel sheathing will give you an acceptable test result.
See the Dave Ward videos on TT

 

[DPG]

Hi All
DO NOT RELY ON THE SWA WIRE SHEATHING FOR EARTHING TO AN OUTBUILDING !!!!
Disconnect one end of the sheathing and use it only as an earth protection for the feed cable. Then provide a dedicated earthing method for the out building.
It is unlikely the steel sheathing will give you an acceptable test result.
See the Dave Ward videos on TT

Are you sure about this?

What would be the advantage of two separated TT systems in this case?

 

[westward10]

Hi All
DO NOT RELY ON THE SWA WIRE SHEATHING FOR EARTHING TO AN OUTBUILDING !!!!
Disconnect one end of the sheathing and use it only as an earth protection for the feed cable. Then provide a dedicated earthing method for the out building.
It is unlikely the steel sheathing will give you an acceptable test result.
See the Dave Ward videos on TT

Really.

 

[davesparks]

Hi All
DO NOT RELY ON THE SWA WIRE SHEATHING FOR EARTHING TO AN OUTBUILDING !!!!
Disconnect one end of the sheathing and use it only as an earth protection for the feed cable. Then provide a dedicated earthing method for the out building.
It is unlikely the steel sheathing will give you an acceptable test result.
See the Dave Ward videos on TT

Obviously you can't use the sheath, it's made of plastic!

There's no reason you can't use the steel armour of the cable though, that's one of the things it is designed to do!

The steel armour will give you perfectly acceptable test results if it is installed correctly.

 

[James]

Hi All
DO NOT RELY ON THE SWA WIRE SHEATHING FOR EARTHING TO AN OUTBUILDING !!!!
Disconnect one end of the sheathing and use it only as an earth protection for the feed cable. Then provide a dedicated earthing method for the out building.
It is unlikely the steel sheathing will give you an acceptable test result.
See the Dave Ward videos on TT

What would you consider to be an acceptable test result?
Watching videos is not a bad way to learn some information but the particular site and circuit layouts can massively affect the type of protection required.
therefore a full understanding of the differences in earthing types is likely to be required before you can say what is or is not acceptable.

I would say that as the installation is TT earthing throughout then there is no advantage in separating the earth of an outbuilding to the earth of the supply

 

[MJPD29]

Hi All
DO NOT RELY ON THE SWA WIRE SHEATHING FOR EARTHING TO AN OUTBUILDING !!!!
Disconnect one end of the sheathing and use it only as an earth protection for the feed cable. Then provide a dedicated earthing method for the out building.
It is unlikely the steel sheathing will give you an acceptable test result.
See the Dave Ward videos on TT

No no no no no no no

 

[Jim_e_Jib]

No no no no no no no

No no no no, there's no limits! (?)

 

[littlespark]

No no no no, there's no limits! (?)

Listen to the Scottish version….
It’s called “no lager”

 

[pc1966]

I think the original was 'no lyrics'