Thread (whole nut actually) gine on pattress box

[reb78]

So the young lad who we thought we would give a chance to last year, who is apparently a qualified electrician has not only stripped but completely lost the little nuts in some of the pattress boxes for the kitchen plugs in one of the cottages. The boxes are probably too big to get through the splash backs! Is there something i can screw into the hole that will then take a normal faceplate screw?

One side was ok so it just looked wonky but when I went to tighten it up it was apparent there was nothing to screw into.

I have had to redo so much of what this prat has done. How he can sign off safety tests is beyond me.

 

[Maker]

You could probably get away with a helicoil if you can't get the box out, you will of course have to pay for an M3.5 helicoil kit that you'll never use again.

 

[ajlelectronics]

Smash the plastic box out and replace it with a plasterboard type?

 

[reb78]

He has done it on the cooker faceplate too!

 

[Dee J]

There's not much you can do to fix the threads in plastic boxes. Sometimes you can retap the brass inserts (TLC electrical sell a 3.5 MM tap set in a screwdriver handle just for that purpose). Otherwise trim the splashback with an oscillating saw and replace the box.

 

[anto44]

Could you fill the holes with chemical metal or similar and then drill and tap

 

[reb78]

I was wondering about aralditing one of these in?

Extension Stud 3.5 x 35mm | Toolstation

Extends fixing lugs in metal back boxes by up to 35mm. For use when box is set too deep for socket or switch screws.

www.toolstation.com

 

[Seadog]

You've nothing to lose, except money.

 

[brightspark]

as above smash or cut the box out but put a metal back box in and screw it back . bite the bullet and dont fanny on

 

[MetalMonkey]

In fairness, some of those plastic boxes are terrible for the nuts just dropping out. Sometimes they even come pre-denutted direct from the supplier.

I personally wouldn't have screwed on to the wall behind.
I'd say crack/snip the old box up and remove it in pieces. Then fit a drylining box into the splashback - hopefully with some careful use of a multi-tool it won't end up oversize.
Worth checking before hand, and perhaps taking a few minutes to make up a template so you can fiddle it about a bit to work out how to get the best fit.

 

[reb78]

In fairness, some of those plastic boxes are terrible for the nuts just dropping out. Sometimes they even come pre-denutted direct from the supplier.

I personally wouldn't have screwed on to the wall behind.
I'd say crack/snip the old box up and remove it in pieces. Then fit a drylining box into the splashback - hopefully with some careful use of a multi-tool it won't end up oversize.
Worth checking before hand, and perhaps taking a few minutes to make up a template so you can fiddle it about a bit to work out how to get the best fit.

He supplied the back boxes so a problem he created I guess!!

Thanks for the advice though. I will get back to it tomorrow. Our builder and plumber are great. This 'electrician' is laughable. Destroyed a ceiling routing a wire then laughed about it when he told me - I had already shown him an easier route!

 

[reb78]

Also, why leave the job knowing you have done this - the screws were just turning, not even tight, you couldnt miss it if you had done them up!!

 

[S-Rail]

Just cut it out , bin it off and fit a metal pattress back in , won’t take much jiggling to do . Really don’t see why he screwed a dry lining box in .

 

[reb78]

The wall gets damp and the galv back boxes eventually rust - i think that was the idea with plastic. Its an old stone cottage.

 

[MetalMonkey]

Really don’t see why he screwed a dry lining box in .

Looks like a normal plastic box not a dry liner to me - no lugs.

 

[Dee J]

Looks like a normal plastic box not a dry liner to me - no lugs.

MK do (or did) plastic flush back boxes (for wet plastered walls, not drylining boxes) . I've used them myself in old walls known to have rusted out metal boxes - though I suspect in the OP's case these are actually normal surface back boxes trapped behind the splashback - so will need breaking up to remove.

 

[Sergei Slovenija]

Sometimes, a thermal gun with a stick of polymer glue helps out a lot.

 

[Onoff]

You can get heat inserts in M3.5. 7.1mm dia though, used by "us" who 3D print. About 7mm dia though.

Heat & Ultrasonic Threaded Inserts unheaded - Brass - M3.5 x 7.1mm | Shop4Fasteners

<ul><li>Thread Pitch: 0.6mm</li><li>Outer Diameter: 5.43mm</li><li>Recommended Hole Size: 4.8 - 4.9mm</li></ul>

shop4fasteners.co.uk

Is there an old one come out you can measure?

"Knurled brass inserts" another term.

 

[Onoff]

5.4mm diameter:

RS PRO, M3.5 Brass Threaded Insert, 5.4mm diameter 4.8mm Depth 7.1mm | RS

uk.rs-online.com

 

[Onoff]

...could even 3D print a complete new back box...