Recommended metal backbox sizes

[steve1811uk]

Hope someone can help with recommended backbox sizes for the following:

Unswitched single socket
Unswitched 20 A flex outlet
Switched FCU
45A cooker switch (without socket)
45A CCU
Switched double socket

I had a quick look but didn't see this info anywhere. Cheers, Steve.

 

[davy_owen_88]

It depends on the cable sizes being used. Here's what I use:

1-1.5mm² - 16mm
2.5mm² - 25mm
4-6mm² - 35mm
10mm²+ - 47mm

There's no benefit in cramming cables into smaller back box' just for the time saved in making the chase 1cm shallower. It's false economy, you spend longer fussing with the cables and risk damaging them.

Davy

 

[FredFlintstone]

I find it's worth stepping up a size to prevent fussing round with cables and trying to squeeze them behind the fitting. As Davy points out - it ain't worth trying to save time on the chasing because any time saved will be lost messing with cables.

Regards

Fred

 

[sparkybird]

Also kinder to your cables not to have them scrunched up in the box!

SB

 

[steve1811uk]

Thanks for all the replies. I'm going to use 25mm for everything except the cooker switch and ccu which will be 35mm. Steve.

 

[dw3101]

I've been caught out in the past by people buying cheap dimmers,

I fit 25mm as a minimum for all light switches, and 35mm where possible if its 2/3 gang and possibly 2 way..

2 mins more chiseling = no return visit.

Make sure your cooker isolators are double gang if using 10mm² cable - it makes life easier, as for shower isolators

 

[Taylortwocities]

Beware if you are planning to fit 'flat plate' sockets etc. The depth from front to back of some of these is about 25mm so there's no room for any wires.
I fit 35mm for sockets & FCUs if poss so there space to play with.

TTC

 

[dw3101]

No one other than women plan to fit them

Whats wrong with the MK logic range, other than crap screws.

David

 

[RF Lighting]

I have flat plate brass in my kitchen which I chose.



Whats wrong with MK logic? They haven't made it for about 15 years

Logic plus? Have you seen the switches? real cheap and nasty nowadays

 

[Steve]

No one other than women plan to fit them

Women dont plan to fit sockets at all! "Oh did you have to put a socket there?" and "What do you mean that socket looks nicer? They are all Fugly"

 

[securespark]

Thanks for all the replies. I'm going to use 25mm for everything except the cooker switch and ccu which will be 35mm. Steve.

May get away with 35, but 47 'd be easier.

 

[Taylortwocities]

Take care when chopping holes for a 47mm box in Thermalite, etc. One whack too hard and you will be looking into the wall cavity.

TTC

 

[dw3101]

Whats wrong with MK logic? They haven't made it for about 15 years

Logic plus? Have you seen the switches? real cheap and nasty nowadays

Sorry I meant logic plus.. The screws are really crap IMHO on them.. look nice but thats it..

As your in leeds, not that you'll care but Falcon do some BG sockets that are copies of the logic plus and they are quite nice. Price is quite friendly on the back pocket too.

David

 

[securespark]

Logic plus? Have you seen the switches? real cheap and nasty nowadays

Yeah. All terminals in line. Remind me of some really old-fashioned (Italian, I think) rectangular switches I took out of a 5/60's install in the early 90's. Pure tat.

Their Cu's have gone utterly down the pan too. Ever compared the old Sentry with the new crud?

And their pendants. As I keep saying, they are the same as really cheap 69p ones I used to get from Denmans (their budget budget budget trade range ).

I won't use them anymore. They still demand the earth for their stuff, but thankfully, gone are the days when every BC company, councils, etc insisted on specifying them. Hurrah. Death to MK, that's what I say.

Rant over!

 

[RF Lighting]

Logic plus? Have you seen the switches? real cheap and nasty nowadays

Yeah. All terminals in line. Remind me of some really old-fashioned (Italian, I think) rectangular switches I took out of a 5/60's install in the early 90's. Pure tat.

They remind me of the 1970s tenby range.