Cannot get wires to fit into back box.. What's the solution

[EFLImpudence]

You need an FCU with a flex outlet and cable grip -

 

[Mr Sparkle]

@EFLImpudence thank you.

will be purchasing a FCU with flex outlet and cable grip..

I really want to improve my knowledge of residential electrics.. Does anyone have any advice regarding books, courses (adult) or online sources that could be useful?

 

[terryplumb]

The switch that you are fitting ,what exactly is it replacing ,what was there before ,a programmer ??

 

[Mr Sparkle]

@terryplumb Presently, there is a FCU. However it doesn't have flex outlet and cable grip

 

[terryplumb]

Your original pic shows a lot of unconnected conductors ,as though you are fitting the accessory. I am asking what was there before. The pic isn't very clear ,but it appears to me that there is more than the boilers cable connected to the load side.
If there was a fcu there originally ,why are you struggling to fit a replacement ? Something don't seem right ?

 

[Mr Sparkle]

There is wiring for a thermostat

 

[terryplumb]

And where is the programmer being connected ?

 

[DetlefSchmitz]

I think you really need to describe everything you have done, right from the beginning, and the reason you are doing it. Otherwise no-one can really help. There is something about this that doesn't make sense without more information from you.

 

[333rocky333]

The position of the T and E cable entry suggests its at least a 25mm box, use smaller connecters on the unused cores, use smaller earth sleeving, trim the conducters back a bit and get a decent accessory like an MK with a smaller back and that should fit.

 

[Mr Sparkle]

Brilliant - thanks @333rocky333

 

[ban-all-sheds]

Does anyone have any advice regarding books, courses (adult) or online sources that could be useful?

• http://www.diynot.com/wiki/Electrics

Sadly no longer up to date - the Wiki package on this site is such a PITA to use that it discourages people from writing and editing articles. Don't rely on the links - search for the titles.

• http://kevinboone.net/electricity.html

• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/domesticinstallations.html

• http://wiki.diyfaq.org.uk/index.php/House_Wiring_for_Beginners

• http://www.diynot.com/wiki/Electrics

 

[JohnD]

there are little pocket books like "On-Site Guide" and "Electrician's Handbook" but they are more to remind you of things you already know, or look up details. They (should) change with each new edition of regulations, and each version is a different colour. Your library will have them but often it will be an out-of-date copy.

When you see them on sale, the cheap ones will be out of date.
https://www.ebay.co.uk/sch/i.html?_....l1313&_nkw=electrical+on+site+guide&_sacat=0

If you are a voracious reader you can read through the whole thing but they aren't intended for that.

Old ones can be very interesting historically.

 

[ban-all-sheds]

When you see them on sale, the cheap ones will be out of date.
https://www.ebay.co.uk/sch/i.html?_....l1313&_nkw=electrical+on+site+guide&_sacat=0

Yes but yes but yes but...

If you are starting from a low base, then out of date guides can still provide useful information on the basics, as long as people remain aware that the material is out of date in some way.

It's a bit like looking at old maps - the positions of lines, and the names and colours of the areas they enclose, may have changed, but the coastlines, rivers, mountains, deserts, major cities etc haven't.

This is going to teach people useful things despite being dated.

 

[sparkwright]

Your original pic shows a lot of unconnected conductors ,as though you are fitting the accessory. I am asking what was there before. The pic isn't very clear ,but it appears to me that there is more than the boilers cable connected to the load side.
If there was a fcu there originally ,why are you struggling to fit a replacement ? Something don't seem right ?

It looks simple enough to me.

Two 2.5mm2 supply cables, and a 3 core+e cable for the roomstat which interrupts the flex to the boiler.