Extending electric cable

[sparkwright]

You shouldn't need a blank plate if you use a maintenance free junction box. However, if the wiring is not in a prescribed 'safe zone' or at least 50 mm deep from each side of the wall, there could be issues.

I would have thought the wiring comes from above. If so, I would consider doing the joint above the ceiling. Is there access above? If not, you may have to cut a neat hole in the ceiling above the existing switch.

There the joint can be made, and a new cable run from here, fished across the ceiling towards the new switch position.

It would be very handy to see photographs of the existing wiring, as we are doing a lot of guessing.

You can't run cables round the door frame behind the architrave as it's not allowed. Cables have to be run in safe wiring zones - which usually mean running cables horizontally or vertically in line with an electrical accessory, or within 150 mm from a corner or ceiling.

I'm sure someone will send a drawing of the safe zones...

By running the cable round the door frame and covering it up, no one knows the cable is there. It's not in line with an electrical accessory, so no one would expect it to be there. So therefore it may get damaged, particularly by someone fitting door hinges or nailing on architrave...

You mention 3 core electrical cable. What's that? You need 1.0 or 1.5 mm2 two core and earth flat cable.

PICTURES please.

 

[masscrazy]

I take the point about no one know about the cable going around the door. But once in who touches the architrave? Clearly im missing something.

PICTURES please.

As requested - let me know if you need more.

Few more details. This is a loft conversion, plaster board has been installed plastered and also painted. The door was originally supposed to open the other way but due to the alcove the position of the door was changed. And so this problem. It will be very tricky to make use of the existing cables routes.

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[sparkwright]

Your best bet is cut a neat hole vertically above the old switch, no more than 150 mm below the ceiling. Pull out the old vable here.

Then fish horizontally the new cable across towards the new switch position. You will have to notch the plasterboard where the uprights are, again less than 150 mm below the ceiling.

Then pass the cable vertically downwards towards the new position. There will probably be a cross member (noggin) in the way. Again notch the plasterboard, vertically in line with the switch box.

At the neat hole you cut just below the ceiling, join the old cable to the new cable using a 20 amp maintenance free junction box. Hager are best, available from most electrical wholesalers. Use earth sleeving on all bare earth wires.

It may sound like a fuss doing all this, but it should comply to regs.

The cable you are joining onto is called 3 core and earth cable.

 

[masscrazy]

Problem is however there are vertical wood beams for the walls. So running the cable across above the door nearer the ceiling will mean having to drill into each beam. There is no way of doing that without taking a massive chunk out of the plaster board.

Any other possibilities?

 

[RF Lighting]

What's above the room in your picture?

 

[sparkwright]

As I said, you notch just the plasterboard where the wooden studs are. You don't need to drill or chissel the wood. Just the plasterboard. You fish the cable in the void behind the plasterboard, and run the cable over the studs in the plasterboard notch.

Clip the cable to the wood in these notches, and fill over. As they will mostly be within 150 mm from below the ceiling, they will be out of eyeline, so when filled and painted you shouldn't see anything.

 

[ekmdgrf]

I take the point about no one know about the cable going around the door. But once in who touches the architrave? Clearly im missing something

I don't know what sort of person would put a screw into a door frame. Probably the sort of person that would think "what sort of person routes a cable through a door frame? I must be missing something!" if they did.

I think what you are missing is that while the probability of someone doing it is low, the consequences of doing so could by really quite bad, like them getting electrocuted or setting their house on fire. If not that, well you've seen yourself what a ball ache it is to route a cable. Imagine putting a screw through a door frame into a cable and then having to repair the mess.

I see that the roof appears to be flat. Is there a small void above that is accessible so that you could crawl in and get at the cable from there? You might find that you can free up enough cable to drop it straight down to the new position.

Another option might be to run the cable vertically down from the old switch, under the floor and then vertically up to the new switch? Let me guess, you've just laid the laminate floor?

What is the other side of that door? Maybe you could attack the plasterboard from the other side?

Maybe there is another radical solution, pull chord light? PIR? Some other kind of occupancy sensor? Light switch on the other side of the door?

The problem is that running cables is a destructive, messy and annoying job. It's made 1,000x worse when the room has already been completed.

Maybe it would be easier to look at finding a way to swing the door the other way?

 

[masscrazy]

What's above the room in your picture?

Its an alarm sensor (also put in wrong place). Thats a question for another thread, what to do about putting it right in the corner

As I said, you notch just the plasterboard where the wooden studs are. You don't need to drill or chissel the wood. Just the plasterboard. You fish the cable in the void behind the plasterboard, and run the cable over the studs in the plasterboard notch.

Clip the cable to the wood in these notches, and fill over. As they will mostly be within 150 mm from below the ceiling, they will be out of eyeline, so when filled and painted you shouldn't see anything.

Ah, sorry had to make to spell it out, but that makes alot of sense. I think I will do that. Nice idea!

I take the point about no one know about the cable going around the door. But once in who touches the architrave? Clearly im missing something

I don't know what sort of person would put a screw into a door frame. Probably the sort of person that would think "what sort of person routes a cable through a door frame? I must be missing something!" if they did.

I think what you are missing is that while the probability of someone doing it is low, the consequences of doing so could by really quite bad, like them getting electrocuted or setting their house on fire. If not that, well you've seen yourself what a ball ache it is to route a cable. Imagine putting a screw through a door frame into a cable and then having to repair the mess.

I see that the roof appears to be flat. Is there a small void above that is accessible so that you could crawl in and get at the cable from there? You might find that you can free up enough cable to drop it straight down to the new position.

Another option might be to run the cable vertically down from the old switch, under the floor and then vertically up to the new switch? Let me guess, you've just laid the laminate floor?

What is the other side of that door? Maybe you could attack the plasterboard from the other side?

Maybe there is another radical solution, pull chord light? PIR? Some other kind of occupancy sensor? Light switch on the other side of the door?

The problem is that running cables is a destructive, messy and annoying job. It's made 1,000x worse when the room has already been completed.

Maybe it would be easier to look at finding a way to swing the door the other way?

Haha thanks for the info, you've convinced me the door thing is a bad idea. Although using sparkwright technique seems to expose the cable even more than with the architrave way. Since its being run behind a bare wall where someone could screw/nail something in...no? So more riskier than architrave approach..?

The roof is flat but is filled with solid insulation so no room to crawl.

Fortunately its still bare chipboard on teh floor, but the skirting is in and filled and decorators caulk applied for gaps. So dont want to remove. And even if removal was not required is seems more efforts to remove chipboard from the floor to run the cable.

So as suggested by sparkwright, I'll run the cable across the door and attach the new length of cable and run down to new switch.

Next question: How to join to lengths of cable? This definitely not a viable option then? A maintenance free junction box, can this be put into the wall, attached to the wood beam and covered?

 

[ekmdgrf]

There's a trio of problems with that connection block:

1) B&Q describe it as "Ideal for low voltage lighting terminations and areas where high temperature may occur." I don't think they mean the BS 7671 definition of "low voltage" (50-1000V AC). Rather, I think they mean 12V

2) It has screw terminals and therefore need to be "accessible for inspection"

3) The terminals are exposed and need to be "accessible only by means of a tool"

 

[masscrazy]

There's a trio of problems with that connection block:

1) B&Q describe it as "Ideal for low voltage lighting terminations and areas where high temperature may occur." I don't think they mean the BS 7671 definition of "low voltage" (50-1000V AC). Rather, I think they mean 12V

2) It has screw terminals and therefore need to be "accessible for inspection"

3) The terminals are exposed and need to be "accessible only by means of a tool"

Sooo maintenance free junction box and OK for it to be covered/in the wall?

 

[masscrazy]

bump

 

[bernardgreen]

I don't know what sort of person would put a screw into a door frame.

People who fit door hinges ?

 

[masscrazy]

The technique to create notches in the plasterboard is going to be very messy and tricky, as I dont know whether the cable has been tacked to the wall beams etc etc.

Any one else have an idea of how to get the cable to the otherside?

 

[EFLImpudence]

The technique to create notches in the plasterboard is going to be very messy and tricky, as I dont know whether the cable has been tacked to the wall beams etc etc.

Our work is very messy and sometimes tricky; that's why we're allowed to charge up to half of a plumber's rate.

Any one else have an idea of how to get the cable to the otherside?

I think you have been told the methods.

As long as the cable remains safe and in the prescribed zones you can use any method you choose.

 

[masscrazy]

The technique to create notches in the plasterboard is going to be very messy and tricky, as I dont know whether the cable has been tacked to the wall beams etc etc.

Our work is very messy and sometimes tricky; that's why we're allowed to charge up to half of a plumber's rate.

Any one else have an idea of how to get the cable to the otherside?

I think you have been told the methods.

As long as the cable remains safe and in the prescribed zones you can use any method you choose.

And a maintenance free junction box is what is needed to join the two cables and ok to buried into the wall?