Cannot secure switch to backbox

[AndyPRK]

In the 1960s the. Used BA screws

 

[Mr Sparkle]

Has the property been rewired, if not there is a good chance the lights will not be earthed, could cause some issues if metal lights or switches are fitted

The property has been part rewired. However the lighting circuit went untouched

Nevertheles, all of the lighting in the property has earth cabling.

 

[Mr Sparkle]

In the 1960s the. Used BA screws

Thank you

Can these be picked up at a electrical wholesaler? Or any shop on the streets.. Or does one need to order online only?

Also, can these screws be cut back (in case they are too long)

 

[AndyPRK]

You won’t get them in normal shops.

Online only if you are lucky

 

[AndyPRK]

Something like this but I’m guessing.

Maybe someone else can confirm.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/371148856522

They can be cut if required

 

[securespark]

I've done that before.

 

[Mr Sparkle]

Something like this but I’m guessing.

Maybe someone else can confirm.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/371148856522

They can be cut if required

So just to confirm, i require '4BA' screws as suggested by @flameport?

What would be the standard length please?

 

[Mr Sparkle]

I've done that before.

Cut them?

 

[securespark]

When I posted that reply the last post I could see was the YT film with COVID. It was referring to the fact that I have dealt with a broken lug by drilling and tapping the back of the box.
But yes, I have also cut screws down. What I have also done (in the absense of 4BA screws) is to rethread a gammy 3.5mm lug with a 4mm threading tool, then use a 4mm slotted CSK machine screw.

 

[sparkwright]

@sparkwright top man!

Just so that i have it right, after inserting the yellow plugs, i should use the 3.5 rethreading tool inside the yellow plug?

If the screw is too long, what could happen?

I threw out the old screws.. i assumed that all back boxes (especially in a home built in the last 60 yrs) would use 3.5 screws

The rethreading tool will help you to form a thread to help you getting the new screws in.

Not essential, but will make life easier. You could use a small wood screw to make a start.

(You could in fact use wood screws to fix the switch plate back, but it's not ideal to have sharp threads near electrical wires.)

If the screws are too long you risk pulling out the wall plug and/or breaking the brickwork around the hole.

 

[Mr Sparkle]

Update

Job done (i hope)

This thread may help someone one day, so I'll explain what i did.

1. Turn off power and remove faceplate.

2. Used a 5mm bit and drilled straight through the lug into the masonry. Initially, i tried to remove the plastic lug but couldn't.

3. Inserted Yellow plugs through the lug and into the masonry behind. Used rethreaded tool in the plug and inserted M3.5 screw

And its held very firm. I just hope that this is the end and the switch won't mysteriously come loose one day

Thanks for your help guys. @sparkwright you are a genius!

 

[SUNRAY]

They maybe not be gone. If using too small screws that’s maybe the problem.


See at 6 mins.

And interesting idea.

Yes a good idea but it really should be a 2.8mm drill for m3.5 thread.

 

[delmel]

All boxes as far as I recollect in the last 30 years the boxes are 3.5mm thread not 4ba unless what she has is an old metalclad unit then it may have. But if its jus a metal back box in the wall 3.5mm screws which are very widely available.

 

[AndyPRK]

I used a 2.9mm drill and it threaded ok.

 

[delmel]

must have just had a bit of crap in it, you can get a little hand 3.5mm tap tool to either clean out or rethread should it occur again