Patress Boxes and Rubber Grommets

[pundabuyer]

Hi Guys, Just wondering if rubber grommets have to be fitted to the metal back boxes? is this a 'should do' or is it a must?

Thanks

 

[holmslaw]

..

 

[pundabuyer]

Thanks, as long As it's not regulation I'm happy

 

[OwainDIYer]

It needs to be there - it's good practice, and an ungrommeted entry on a metal CU is a fault you can be tested on for C&G Insp and Test.

 

[PrenticeBoyofDerry]

Grommets should be fitted, cables can be damage prior to or during plastering, if an Inspection and Test was done it would be flagged up!

 

[Bill Stickers]

Not important, once plastered the cable cannot be damaged, and if in dry lining the cable is not moving about once everything is finished.

You rough b'stard

 

[Risteard]

I take holmslaw's point, however don't forget that cables do vibrate in service.

 

[OwainDIYer]

I take holmslaw's point, however don't forget that cables do vibrate in service.

They also get warm, and insulation changes shape under pressure.

 

[mfarrow]

This is something I was going to ask (sorry if I'm hijacking anything).

What do you do if the boxes are already plastered in, i.e. there's no way to get a grommet to fit in there? Will this be flagged up on a PIR, and is there any other protection (i.e. shrinkwrap) which should be considered instead?

 

[ban-all-sheds]

What do you do if the boxes are already plastered in, i.e. there's no way to get a grommet to fit in there?

Nothing.

Will this be flagged up on a PIR,

You'd need to be pretty picky to do that. If I understand you, the cable is embedded in plaster up to and including the hole in the box, which is why you can't get a grommet in, in which case the cable can't move around and chafe on the edges of the hole.

and is there any other protection (i.e. shrinkwrap) which should be considered instead?

Again - if the plaster is where I think you're saying it is then how could you get anything round the cable which would go through the hole and out the other side?

It is a bit rough not to have had grommets in the first place, but now that it's done it's done, and you aren't going to win many friends by filing PIRs with Code 2s for everything you find that you think is a bit rough.

 

[Risteard]

If there's no evidence of damage and no way the cable can migrate towards sharp edges then adding a grommet after the fact will achieve nothing.

 

[PrenticeBoyofDerry]

But it was a new socket back box that was being installed, a grommet should be regardless of the fact it is getting plastered over.
When I was doing my Inspection and Testing course work, I was told to inspect for missing grommets!

 

[Chri5]

But it was a new socket back box that was being installed, a grommet should be regardless of the fact it is getting plastered over.
When I was doing my Inspection and Testing course work, I was told to inspect for missing grommets!

And I've done remedials on 3rd party PIR's detailing the same !

If you split a grommet, you can fiddle about and get the grommet in on a box with in situ cable.

And there's always grommet strip, which has a lower profile and works best where there's sod all room.

 

[holmslaw]

..

 

[sparkwright]

You can still fit the grommets if you carefully chisel round the cable with a screwdriver. There is about a quarter of an inch of plaster around the box that gets covered by the faceplate.

If you haven't second fixed, it would be wise to fit them now.