should be simple ....upgrade front plate on light switch

[awaywiththeowls]

first time poster, don't shoot me down please...ive come here for help!

Attempting to do a simple household upgrade on lightswitch in bedroom however the cables coming from the wall into the existing switch when i loosened the front plate are all in red sheath. 3 single copper twisted cables all in their own red sheath. Two are inserted into the screw hole in the front plate marked common and one into another screw hole. There are three screw hole in total.

I have bought a new plate which looks identical to the old one except its new. So...am i safe to just insert the cables in the same way as the current one? Of course Im sure i am but worried as there is no obvious earth and i dont understand why 2 cables are inserted into the one hole. Educate me please guys, im a budding female diy-er dont be mean now! The house is 1964 built. Appreciate this.

 

[RF Lighting]

You have a standard circuit.

The live wire comes from the fuse box and into the first light switch. From the first switch it goes to the second switch and so on.

This is why you have two wires in the same terminal.

You then have a third wire which is the switched live in it's own terminal. This takes power from the switch to the light when the switch is on.

This is know as either 'singles' or 'conduit' wiring method. I can't seem to find a diagram at the moment.

Anyway, if your wiring is the original wiring from 1964, then it probably isn't earthed, and may even be rubber sheathed wiring. This means you must NOT fit any metal switches or light fittings. Plastic switches will be ok, but still great care must be taken not to damage any of the wires whilst fitting the switch.

It would be a good idea to have your wiring checked over to find out what condition it is in.

If you put a few photos of your switch wiring, and your fusebox and anything else you think may be of interest, we can give you a very basic indication of how old your wiring is, and a rough idea of what condition it might be in.

 

[awaywiththeowls]

Thats really helpful thanks for the speedy reply. I will get some pics up over the weekend, appreciate the help. The switch i have bought is just a plastic one no metal. Will post again when i have taken some snaps, cheers for the help!

 

[PrenticeBoyofDerry]

What you have as RFL has stated above is your permanent live (two red cables at common connection on the switch) being "looped" in at the switch point.
And the third red cable at L1 making the live connection to the light fitting when the switch is closed and breaking it when open.
The permanent lives will be start at you fuse board from the circuits fuse, then loop in to each switch on that circuit at the common terminal. The last switch on circuit, will only require one permanent live as it is the end one and goes nowhere after that.

The neutral conductor will then be "looped in" within the ceiling/floor void, to each light fitting, again starting at the fuse board at the neutral busbar.
You would expect to see two neutral conductors at each fitting until the last one on circuit.
Depending on the age of the installation you may find that the circuit protective conductor (earth) has been cut back and still within the insulation of the cables or sometimes tucked out of sight. So worth investigating for that.
But for you to have earth continuity, you must have all earths connected at every accessory and terminated back to the earth busbar at fuse board.
You would need some electrical testing equipment to confirm this.
If no continuity of earth, then you must only us plastic or double insulated accessories at switches and lights.

 

[awaywiththeowls]

Thank you, I will have a better look this weekend and wont attempt any more 'fiddling' until then. I did have an electrical condition report prior to moving in which advised a rewire however funds being what they are when you move into your first 'home' i just cant afford that so hoping to make some small safe cosmetic changes then look at having a rewire when we win the lottery...! Thanks again i'll post some pics over the weekend of the other things im hoping to update just to check im doing that right too.

Thanks guys for not being bulshy too, sometimes people who reply to posts seem to have such an attitude that puts me off asking questions, much appreciated again, have a good weekend.

 

[PrenticeBoyofDerry]

For what reasons was a rewire recommended?

 

[awaywiththeowls]

Have uploaded a few photos andn supplied details of the condition report to add some meat to the bones.

Having changed the light switch in my first post, with no problems i wish to see if i can do the same for the plug socket in the room. It is the only socket in the entire room so was also wanting to know if it would be advisable to fit a double socket or just re-fit like for like and use and extension or double socket plug. Any ideas would be much appreciated.

The rewire was reccomended following a installation condition report. i'll list some of the remarks that stand out as its a very long report and see if anyone wishes to translate from spark speak into english for me....

* Supply Characteristics- TN-C-S
* type of live conductors- 1-phase (2 wire)
* Supply protective device- BSEN- 1361 Fuse HBC,(Type 2)
* means of earthing - distributors facility
* bonding of incoming service- water, gas,( protective measure against shock ADS)
* Main switch/Switch fuse/RCD- 5419 isolator, copper conductor, 2 pole, 16mm
* Circuit details- 1- cooker, 2- sockets, 3- immersion heater point, 4- lights downstairs, 5- lights upstairs, 6- Spare.
* Type of wiring- listed against all above circuits is PVC/PVC cables
* Reference method- PVC cables in non-metal conduit


Observations --

Many! over 100 C3, 43 C2 and 5 C1...

The C1's are
1) Distribution Equipment--Examination of protective devices and bases: correct type and rating
2) Final Circuits- Wirign System appropriate for type and nature of installation
3) Final Circuits used to supply mobiel equip not exceeding 32 A rating for use outdoor in all cases
4) Final Circuits- for all socket-outlets of rating 20 A or less provided for use by ordinary persons unless exempt
5) Distribution Circuits- General condition of wiring system

sorry photos not uploading, will try again in a bit

 

[securespark]

Is that all they wrote?

Need more info.

 

[PrenticeBoyofDerry]

Don't get some of the code 1s,
Why are they code 1s? Need more info.
I assume 3 and 4 relate to RCD protection but the rest?
Is there anyway you can scan and upload the documents given?

 

[kai]

If your installation is really that old (pre-1964 etc), it may be well past its safe working life, depending on the material used in the cables etc, there may well be "green goo" oozing from the cables, brittle cable insulation, and you are best to leave it undisturbed until rewiring time.