new pull cord - electrical screws

[HawkEye244]

Having a problem trying to fit this new pull cord to what is existing in the ceiling. The threads are at least two sizes different, approximately m6 equivalent. The trouble is that anything thicker than an electrical screw will not fit through the actual pull cord.

 

[DetlefSchmitz]

If the holes line up you can epoxy a nut of the right size above the oversized hole.

 

[ericmark]

Depending on age either 2BA or 4 mm are normally used with conduit boxes. Socket boxes now normally 3.5 mm

 

[sparkwright]

Very likely 2BA, as mentioned. This is an imperial size, but they can still be bought.

You could fit the old screws of course.

These will fit through the base of the pull cord, assuming it's a decent brand that has holes that will line up with the 'besa box' embedded in the ceiling.

 

[HawkEye244]

I appreciate the advice. Sadly the old screws were lost. At least I have a few options then

 

[HawkEye244]

I'm finding that the 2ba screws are not sold in lengths more than about 1inch and a half, I need at least 2 inches to get the depth.

3.5mm nuts are not so common either, that's if sticking them on works at all.

Either way it's going to be an ebay purchase. Ordered them anyway, will report back.

 

[sparkwright]

You do not need 2ba screws that long.

You are simply fitting the white round back box to the besa box embedded in the ceiling.

You then fit the switch front plate to the white round back box, with the screws that came with the switch (these are usually m3.5 or m4.0).

If you can't fix that back box to the box in the ceiling then you have bought a rubbish switch.

 

[flameport]

These are the knockouts used to fix the white plastic box to the conduit box in the ceiling.

They are the same ones you would use for screws directly into a ceiling without conduit.

2BA screws are available from electrical suppliers such as here: https://www.edwardes.co.uk/en/categories/machine-screws-brass-2ba

Hopefully that wiring isn't the ancient rubber insulated type it appears to be.

 

[Risteard]

It should be remembered that the OP is incompetent and a danger to himself and others. He should not be helped under any circumstances whatsoever.

 

[ban-all-sheds]

 

[333rocky333]

You can tap them out if you have a 5mm tap and the 5mm machine screws are easier to get, sometimes easier to get M5 x 75mm toggles to get a long screw, sometimes you need to carefully drill out the pullcord base holes a little to take the 5mm screws

 

[HawkEye244]

You do not need 2ba screws that long.

You are simply fitting the white round back box to the besa box embedded in the ceiling.

You then fit the switch front plate to the white round back box, with the screws that came with the switch (these are usually m3.5 or m4.0).

If you can't fix that back box to the box in the ceiling then you have bought a rubbish switch.

These are the knockouts used to fix the white plastic box to the conduit box in the ceiling.

They are the same ones you would use for screws directly into a ceiling without conduit.

View attachment 129487

2BA screws are available from electrical suppliers such as here: https://www.edwardes.co.uk/en/categories/machine-screws-brass-2ba

Hopefully that wiring isn't the ancient rubber insulated type it appears to be.

Thank you so much that makes sense now. Obviously I was trying to do both in one hit.

I'll see what I can pick up from an electrical wholesaler, have to pop out anyway to pick up a junction box.

 

[HawkEye244]

You can tap them out if you have a 5mm tap and the 5mm machine screws are easier to get, sometimes easier to get M5 x 75mm toggles to get a long screw, sometimes you need to carefully drill out the pullcord base holes a little to take the 5mm screws

I have one of these for electrical back boxes, but not a 5mm..

 

[HawkEye244]

Just to say that 2ba screws were indeed the correct ones and set me back the grand total of 47 pence. Thank you everyone that helped.

 

[ban-all-sheds]

Hopefully that wiring isn't the ancient rubber insulated type it appears to be.

If it is he won't care.