Can FP 200 be burried in the wall without RCD???

[wetny]

Hi. We are looking to quote to install domestic heat detectors interconnected to the existing smoke alarms for a social housing provider. Do you think that FP200 could be used to save us installing RCD protection to the circuit as the cable needs to be concealed. Our NIC inspector tells me that t and e can't be used through the ceiling void because you can't guarantee that it's at a depth of 50mm, so FP would seem to be the way forward. I am aware the the cable is fully screened but only by a foil wrap. Cheers.

 

[WayneL]

Am I missing something.

Does FP200 offer mechanical protection?

 

[Hawk81]

in my opinion fp200 is not the solution. the foil is not protection like swa

 

[pushrod]

why can't you clip the T&E at a height of more than 50mm if it is in a ceiling void?

 

[wetny]

It's not a matter of mechanical protection, more earthed metallic sheath. Without lifting floorboard, carpets and moving furniture, cable can not be clipped. We are talking about 5000 properties, if it was just a few would not be an issue.

 

[WayneL]

It's not a matter of mechanical protection, more earthed metallic sheath. Without lifting floorboard, carpets and moving furniture, cable can not be clipped. We are talking about 5000 properties, if it was just a few would not be an issue.

But the 'earthed metalic sheath' that they are referring to in the regs, (in order to not need RCD protection), is for mechanical protection.

FP200 sheath does not offer this.

SWA, yes. Steel conduit, yes. Earthed steel plate, yes. But not FP200.

 

[wetny]

I would have thought that the purpose of earthed metallic sheath was to provide automatic dis connection rather than mechanical protection.

 

[Hawk81]

It's not a matter of mechanical protection, more earthed metallic sheath. Without lifting floorboard, carpets and moving furniture, cable can not be clipped. We are talking about 5000 properties, if it was just a few would not be an issue.

and how would you earth the foil? sy would be better.

 

[WayneL]

I would have thought that the purpose of earthed metallic sheath was to provide automatic dis connection rather than mechanical protection.

You might actually be right with regards to the requirements of that regulation - I've always took it as 'earthed mechanical protection' that was required - I've never thought of it from the point that you're making, but I've just re-read it.

So the question, as you were asking, is 'does FP200 fit the bill?

 

[Mark_Burgess]

I thought the foil inn FP cable was more for screening purposes rather than ADS.

 

[WayneL]

I thought the foil inn FP cable was more for screening purposes rather than ADS.

I am inclined to agree - does it help towards the fireproofing quality as well? I doubt if it's suitable for the Ops purpose.

 

[Guest123]

How exactly would you "terminate" foil???

Standard FP 200 should be treated the same as T&E.

 

[Hawk81]

How exactly would you "terminate" foil???

Standard FP 200 should be treated the same as T&E.

I made the same point earlier in the thread but it seemed to be ignored

 

[Guest123]

Just backing you up matey.

 

[jimes]

would be a pita to terminate and sheath

 

[Sparky Ninja]

I had a similar issue with interconnecting alarms and concluded with the use of radio linked alarms. I was initially concerned about compliance, however the manufacturers verified it's compliance with Part B 1.21.

The only issue was location, however positions were acceptable in close proximity to lighting points, and the rigidity of the fp200 enabled a 50mm clearance from point to point.

Mr NIC man and Mr Building Inspector were both happy.