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Jamie C · Joined: 16 Nov 2006 Posts: 68 Location: Essex

Gonna be using 50mm Jablite foam sheeting between floors/ceilings to cut down on noise transfer folowing advice previously given here.

Before i start popping it in I thought i oughta check on cable clearance.

Is it a problem to have cables, either lighting or particualrly ring main, resting on top of the jablite sheet?

Or the jablite sheet resting directly on top of cables?

In a lot of places this is going to be unavoidable.

Thanks, Jamie.

AlanE · Posted: Wed Sep 26, 2007 6:33 am Post subject:

Jamie

Heat will be an issue to a certain extent as cables could well run warmer meaning their current rating is reduced but perhaps what could be a more important issue is compatability between the cables and this sheet.

Several years ago expanded polystyrene granules were used as a form of lose fill loft insulation and it was afterwards discovered that this and pvc cables (? might have been another material that the 'plastic' cables were made from at that time - memory bit uncertain there!) were incompatable. The polymer in one migrated to the other causing damage to the cables. This insulation subsequently had to be removed from loft areas.

Plastics unfortunatly have a very complex nature and this migration effect can easily be seen if for example you lay some PVC type cable on the perspex covers popular on record turntables. Store them in this fashon and you will almost certainly find that after a few months or so the cable will be stuck to the lid or that there is a groove in the lid where the cable laid!

Best suggestion would be to contact the manufacturer of this sheet and get their confirmation, in writing, that their product will not cause damage to any electrical cable touching it. Point out your concerns because of the previous loft insulation problem with electrical cables.

Jamie C · Joined: 16 Nov 2006 Posts: 68 Location: Essex

Thanks Alan for the response.

Have contacted Vencel Resil (who manufacture Jablite) tech dept by email on wednesday, no response yet!!!

Found this on the web though -

"Jabfloor 70 should not be allowed to come into direct contact
with PVC-sheathed cable, nor closer than 12mm to hot-water pipes;
pipes should be haunched with a sand/cement mix or lagged using
a proprietary material intended for this purpose".

Are current standard electrical cables sheathed in PVC?

vince knight · Posted: Sat Sep 29, 2007 8:46 am Post subject:

All current cables are PVC

Vince

Jamie C · Joined: 16 Nov 2006 Posts: 68 Location: Essex

Thanks Vince.

Where they are going to come into contact with each other ill put some cardboard between then.

Where we have been cutting the Jabfloor to fit there are some small beads of polystyrene floating around in the floorspace now, will this small amount interfere with the cable outers if left there touching, or do I have to clean that out too?

vince knight · Posted: Sun Sep 30, 2007 2:04 pm Post subject:

It is best if it is hoovered out. When the pvc reacts it turns into sticky goo over time.

Vince

Jamie C · Joined: 16 Nov 2006 Posts: 68 Location: Essex

Thanks, will do it.