Diy double insulation?

[BillyH]

Is it possible to double insulate single insulated cables? For example where a 25mm 3c swa glanded to an adaptable box and then through a hole on the opposite side to, lets say a KMF800 .

 

[telectrix]

heat shrink sleeving. or a bit of pvc trunking?

 

[BillyH]

Would heat shrink be classed as an extra layer of insultion in this case? Mini trunking would still leave part of the single insulated exposed though.

 

[telectrix]

alternative would be to terminate into sheathed tails in the adaptable box. personally, i would prefer not to joint if unnecessary.

 

[Richard Burns]

If you have gland, box, KMF then the single insulated cables will not be exposed as they are either in the cable, in the box or in the switch?

However you could just leave the bedding in place until you are in the switch.

 

[Engineer54]

Would heat shrink be classed as an extra layer of insultion in this case? Mini trunking would still leave part of the single insulated exposed though.

I would say so yes!! All heatshrink sleeving is high grade XLPE, which has a superior insulation value than standard PVC insulation...

Having said that, normal cut-out/ meter tails, are not double insulated, they are insulated and sheathed single cables...

 

[Knobhead]

Just look for 11KV heat shrink terminations and see how they are done. The principal is the same.
Put a layer s of HS over the cores followed by a larger adhesive/sealant lined tube over the cable crutch.

I’ve done it with 45 year old SWA VIR’s when moving a MCC. 30 years on they’re still fine.
Re the VIR’s, the plant they were used in was cool at all times, samples were sent to BASEC for testing. to everyone’s surprise and relief the answer came back, “carry on using them!” We were dreading rewiring over 1000 motors and JB’s.

 

[yellowvanman]

Would heat shrink be classed as an extra layer of insultion in this case? Mini trunking would still leave part of the single insulated exposed though.

As already mentioned the 2nd layer of a cable is usually for mechanical protection rather than insulation.

 

[GLENNSPARK]

I would say so yes!! All heatshrink sleeving is high grade XLPE, which has a superior insulation value than standard PVC insulation...

Having said that, normal cut-out/ meter tails, are not double insulated, they are insulated and sheathed single cables...

yes...and a popular misconception as well that keeps doing the rounds in here is that flat T&E is double insulated.....it isn`t!...the grey or white sheathing is there to contain and protect the insulated live cores and uninsulated CPC underneath...thats all.....