New Sockets..am i being SAFE

[Chrisbarham]

Hi there, i just installed some new plug sockets into my walls, replacing surface mounted sockets.

Anyhow after a lot of chipping away at my wall i managed to get the metal boxes in. However one of the sockets had 3 sets of cabling entering it, so space was rather tight. also much of the cables where far too short so i had too use termianl connectors to extend a few of the cables. I used a 380v terminal connector to extend the reach of a black neutral cable. I then had a a very difficult job pushing the sockets in, but all the plugs are working.

Baicly is using the terminal connector ok, is there any risk involved in using this. i brough a socket tester and all seem ok...

any advise appreciated

 

[Chri5]

I suspect you have used very shallow back boxes, most will supply 30mm+ depth, 25mm ones are pretty restrictive regarding cable inside and more so if metal 'flat' faced socket plates are used.

The jointing of cables is okay inside the box- and NOt ok if elsewhere since a joint under screw termnals will work loose and you could need to service / do remedial work on it later.

Most would opt for crimping cable to extend it, although personally I'd rather re-run a cable than have either an accessable joint box or crimps.

It may work, but I would suggest you consider replacing the back boxes to a suitable depth and replacing the jointed cables.

 

[Spark123]

What is the current rating of the chock block did you use? Is it a 32A Ring circuit?

 

[JohnD]

It sounds like you had difficulty sinking the boxes.

Try this:

Use galvanised steel back-boxes if the wall is of brick or block

draw an outline of the box on the wall with pencil, then slightly larger (half an inch taller and wider, say)

Use your masonry drill to make a row of holes, about 30mm deep (a little deeper than your back-boxes) and as close together as you can get them, all round this outline

Use a Bolster and a Club Hammer to cut through the brick between the holes (it will cut fairly easily), going slowly rounds the outline, say, a quarter of an inch each times, until you have chopped through about half an inch deeper than the box.

Then chop a couple of slots through the "waste" inside the outline, the idea is to divide it into thirds. Eventually the bolster will cause these thirds to crack and fall out (if not, you can bash the bolster diagonally into them)

When you have bashed out the "thirds" you will find the back of the hole is uneven, knock the bolster at an angle across the back of the box and it will knock off the high points. If the block is soft you can hold the bolster firmly and scrape it to and fro across the bottom or edges of the hole and it will scrape off irregularities. Keep putting the box against the hole to see if it will fit in. When you have knocked off enough irregularities, it will fit. The hole will still be irregular, but thats OK, that is why I said make the hole bigger than the box.

Mark two fixing holes through the box against the brick at the back. Drill then to accept a plastic plug. Knock out the holes for your cables and put grommets into them before you fix the box. You may find it easier to put the cables through the grommets before you tighten the screws.

If you are not too good at making holes, I suggest you pack the hole round the back and edges with soft sand and cement mixture, mixed fairly wet with water, after you have started the screws. This will hold it steady even if it is not a good fit in the hole. The screws are important to prevent the box pulling out of the hole. the bricks will absorb the excess water so the mortar will go stiff quite quickly, but you can scrape it out if you have not got it right. Keep it damp for a couple of days to gain strength. You can push in more inyo the gaps round the sides once it is in place.

Pack in mortar but stop before you reach the finished face of the wall, as you will want to skim this smooth with plaster or filler.

It does not matter if the edge of the box is slightly recessed below the finished surface, just smooth the mortar or plaster to the same shape as the box so you have a good rectangular hole.

It is better to wait until the mortar has had a day to harden before you screw on the socket faceplate, or it may pull the box out of place.

This is quite a slow DIY method, but it can give a very good result. If you were a professional electrician you would need to work faster and cut a more accurate hole. Power tools create a vast amount of gritty dust which is unwelcome in furnished and habited rooms.

 

[Chrisbarham]

thanks for the quick replys,

to answer some points, the box is only 25mm deep, the reason for this was that i was moving into cavity walls and the bricks where also very very crumbley, i did not want to go to far in.

Chri5- dont think i got much chance of re-running cable, as it will create to many problems, and what do u mean by crimping cable???

Sparl123 - it is a terminal connector not a choc box and it only says 380v on it. how do i tell what my ring circuit is???

JOhn D- that is the method i used, took ages... i used a load of wickes plaster to fill the gaps, that ok???

so what is the worse that could happen...all the plugs work...all are eatherd to the box and the circuit..what would happen if something pops out????

 

[Spark123]

Chock block is another name for terminal block. I'm not sure how you'd tell if it isn't written on it, how many pieces have you checked? Is it a radial or a ring socket circuit? What size fuse at the consumer unit?

 

[Chri5]

An electric wholesaler will sell you crimps. These can connect 2 wires together without screw connections, they also offer the benefit of insulation to the cable.

Unfortunately a crimping tool costs £10+ and far more if you buy a decent one.

 

[Chrisbarham]

i guess what i really wanna know is, is there any chance of starting an electrical fire, or am i just being paranoid...

 

[Spark123]

The risk is there, yeah. Unless you can tell us the current rating of the block you have installed and information on the circuit then there is little advice we can give.

 

[Chrisbarham]

well its a terminal connector rated at 380v which i think is 15amps...how do i tell what the circuit is

 

[Chri5]

Look at the fuse on the board, a ring main is 30A old fuses, 32A for MCB's

 

[Chrisbarham]

ok just looked, its a mcb made by a company called wylex..its 32a, so what does that mean????

 

[mattylad]

If how I'm reading this is right.....

If your short wire is part of the ring:

That means, your using a 15A connector inline with a 32A ring main.
Which means that the connector is not capable of taking the full load that could be on the ring.

Which means that it will get warm/hot & dry the plastic up, then it will crack and possibly break apart & if it does not melt it is possible that a short could occur & yes your likely to have a little fire in your socket

Chock bloc/connector whatever you wish to cal it, you need to get yourself one capable of the current that may pass through it. If its in the ring then get a 32A one.

 

[jason1958]

To OP.

It might be worth redoing some of it properly since I suspect you are redecorating and thus there is little downside to doing so. Better than using undersized terminal blocks or incorrectly performing crimps (require ratchet tool). Not sure how you have found space to fit a terminal block in a 25mm box without crushing insulation.


1. Backboxes.
- With 2 cables - 25mm box possible, 35mm preferable
- With 3 cables - 35mm box everytime

Some wiring accessories require 35mm (eg, MK sw fused spur).
Likewise lighting often uses 16mm, but dimmers often need 25mm.

2. Terminal connectors
- Whilst meeting "accessible" regs, it is not ideal
- 380V is irrelevant, the *current rating* is critical
- For a 32A CPD you need connector blocks rated to 32A
- This makes them bigger, hence my suggestion to redo it

3. Crimps.
- Crimps are a better & more compact connection method
- Crimps require a proper ratchet tool & care with solid core cable
- Proper crimps & tool will set you back 25ukp

Plier type tools will not produce an acceptable crimp.
Hence cheapest solution is just to redo them.


> I then had a a very difficult job pushing the sockets in,
> but all the plugs are working.

Working does not mean EFLI & IR are still ok.
That is why good workmanship & correct materials is so important.


Sounds like you are redecorating as well?
I urge you to...
- redo the boxes to avoid terminal blocks
- preferably using 35mm boxes where there are 3-cables
- move the boxes slightly if necessary to gain cable length if need be


If the wall is block (light grey breeze, dark black coke cinder)
- Do not SDS
- Use a masonry bit with hammer turned off
- Mark out an outline of the backbox & "stitch drill" around it & within it
- Gently break out/chip out the area

If doing backboxes into internal block, note it can be as little as 70mm.
So with 25/35mm deep boxes it is important not to put them back to back Additionally cutting the block should be done gently, hence I prefer 20mm diamond core bits in a cordless drill to do overlapping holes. Very quick, controlled. Less brutal than a SDS "socket sinker" where slim block walls are on floorboards perpendicular to joists and thus "bouncy".

If the wall is soft brick
- SDS on low speed, don't use a single speed chisel (too brutal)
- Or, narrow hand chisel & lump hammer, slow, but not that slow
- Or, stitch drill with a masonry bit as with block

Some bricks can be almost like sandstone and a screwdriver with a tap will scrape out a backbox. Realise the rest of the wall provides support, just do not break through to the cavity if present on an outside wall. If you do, repair with cement, but do not bridge the cavity with it.


I would not worry about having to move backboxes if need be to avoid terminal blocks, you are only introducing a future failure point. Will only cost you 90p a backbox to redo it, then you know it is done right.

 

[333rocky333]

Did you try gently pulling the cables ,usually there is a bit of slack under the floor.