Mk grid frame to drywall box

bhamoggy · Dec 4, 2021

Will an MK grid frame fit on a drywall back box?
there’s a 100mm cavity behind the plasterboard to the wall so can’t fit metal box

littlespark · Dec 4, 2021

Yes. MK grid frames should be the same standard distance between fixing holes and will fit.

If this is for kitchen appliance switches, let me advise that a deep back box, the deeper the better, should be fitted for ease of installation.
The number of cables behind there can be quite squeeze.

bhamoggy · Dec 4, 2021

littlespark said:
Yes. MK grid frames should be the same standard distance between fixing holes and will fit.

If this is for kitchen appliance switches, let me advise that a deep back box, the deeper the better, should be fitted for ease of installation.
The number of cables behind there can be quite squeeze.

No, it’s for new light switches for a hospital

littlespark · Dec 4, 2021

bhamoggy said:
No, it’s for new light switches for a hospital

Should still fit.

Are hospitals still automatically speccing MK accessories? Been doing that since the 90’s.
No wonder the NHS has no money,

Probably asking for the lights to be run in 2.5 or 4 mm or something.

bhamoggy · Dec 4, 2021

Hahaha
Not NHS, private hospital.
It’s for a double light box, like X-ray in use type of thing

timhoward · Dec 4, 2021

littlespark said:
Yes. MK grid frames should be the same standard distance between fixing holes and will fit.

I agree the hole spacing is the same....but don't the lugs on the side need a recess to fit into?

What I have in mind is that for surface clad metal boxes you have to get the right one as there's one that doesn't have the recesses for the lugs.

[ElectriciansForums.net] Mk grid frame to drywall box

For example, the 3/4 module grid doesn't work with this MK Metal box...

but does work with this one:

Is none of this an issue for the drywall back boxes?

bhamoggy · Dec 5, 2021

Really, you could fit the drywall box and file small indents into the box for the frame lugs to fit over couldn’t you?

SJD · Dec 5, 2021

I've used drylining boxes with grid switches, and although the lugs in the grid means it stands slightly proud of the wall, if you use a screwed grid faceplate with rounded/bevelled edges, it can be pulled into the wall leaving no gap.

There are flat-plate grid faceplates out there, don't use those as you likely will have an issue..

Of course, you could always fit a noggin in the wall, and use a metal box, but I'm guessing that is not an option.

bhamoggy · Dec 5, 2021

SJD said:
I've used drylining boxes with grid switches, and although the lugs in the grid means it stands slightly proud of the wall, if you use a screwed grid faceplate with rounded/bevelled edges, it can be pulled into the wall leaving no gap.

There are flat-plate grid faceplates out there, don't use those as you likely will have an issue..

Of course, you could always fit a noggin in the wall, and use a metal box, but I'm guessing that is not an option.

Yes not really an option for a metal box.

Flanders · Dec 5, 2021

timhoward said:
I agree the hole spacing is the same....but don't the lugs on the side need a recess to fit into?

What I have in mind is that for surface clad metal boxes you have to get the right one as there's one that doesn't have the recesses for the lugs.
View attachment 92616

For example, the 3/4 module grid doesn't work with this MK Metal box...
View attachment 92617

but does work with this one:

View attachment 92619

Is none of this an issue for the drywall back boxes?

Hi you just fold those parts back with a pair of pliers. This is the case for flush mounting any of these.