Twin+E in the roof space

**ians** · 15-Dec-21, 02:24 PM

Installing twin+E in the roof.

The question - what is the right way to install Twin in the roof ... over the rafters unprotected or as many alarm wires are installed up against the plastic out the way (additional heat to to be factored in)

Between the ceiling board and rafter unprotected.

In roof spaces I have noticed people dont take mechanical damage into account ... the wires are installed using the shortest route possible ... in many cases in the walk way ... sometimes while climbing around in the roof ... I shudder to think what will happen if I stand of a twin cable (lighting cable not on the earth leakage).

**LuX10N** · 15-Dec-21, 02:26 PM

Personally I saddle mine on the side op the beams or battons.

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**ians** · 15-Dec-21, 03:29 PM

Originally Posted by LuX10N

Personally I saddle mine on the side op the beams or battons.

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I saw a job the other day where someone had taken the time to clip the cabling along the side of the beam and cross over at the lowest point to prevent damage from people walking in the roof.

If you can get in before the ceiling is installed ... that would be my first choice

I use a wire cable ladder in the middle of the roof if the ceiling is already installed ... the only catch is that extra cable starts adding up ... if the job is quoted then unfortunately it thrown across the roof ... generally the price dictates the installation method.

Sometime you look in the roof and think ... man the sparkie has no pride in his work ... but one can only do what we can within the budget.

**ians** · 15-Dec-21, 03:33 PM

No grey area here ... this crap of people tossing twin+E above the rafter without securing is actually a reg violation ... if you lay the cable on the ceiling ... there is no need to secure it.

6.4.3.4 If a cable is not run on racks or in pipes or ducts, it shall be firmly fixed
to prevent sagging or creeping.
NOTE 1 PVC insulated multicore cables with a bare earthing conductor may be fixed
using adhesives recommended by the cable manufacturer.
NOTE 2 A cable installed in the space above a ceiling and that runs on the ceiling need
not be fixed except at the ends to prevent strain on the conductors or terminations.
NOTE 3 A cable can be damaged if it sags under its own weight.

the joys of working from home ... you get to work even though you are in isolation

I can catch up with the regs ... make up all the tails with my new hydraulic crimper (thanks to Derek) no more hand crimping those big 120/185/240 tails ... assemble the fans for the next project ... save myself wasted time at the wholesaler ... get everything delivered

**LuX10N** · 15-Dec-21, 03:34 PM

Is that from SANS?

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**BEVIN** · 09-Aug-23, 12:24 PM

Hi all. What is the ideal wiring method. In a roof space of 200 mm which has currently no ceiling but will be placed after electrician has done. Conduit? On flat 2 plus earth (rewirable?)

**Isetech** · 10-Aug-23, 08:01 AM

The budget rules all decision, if you have the money its looks nice with conduit and wiring, but in most cases the budget will determine the method, Twin is the cheapest in labour and material, it just doestn look tha good. When you dont want it to look like part of the alalrm or CCTV installtion, just use a 50x50 wire cable tray, it keeps the wiries together, protects them from being squashed by everyone else who climbs in the roof and it keep it apart for the rest of the wire.

We also use differnet colour cat cable for the CCTV so that it can be easily identified.

IF you uave a rat problem then PVC conduit is the way to go, thet cause havoc with allarm and elctrical wires. The roof we are working in at the moment, has a lot of damaged twin, where the rats have chewed through the insulation. If you have pink insulation, the rats love that stuff.

Originally Posted by BEVIN

Hi all. What is the ideal wiring method. In a roof space of 200 mm which has currently no ceiling but will be placed after electrician has done. Conduit? On flat 2 plus earth (rewirable?)

**Thys LOW Elektries** · 12-Aug-23, 04:29 PM

On the topic of Twin + E. I have a wooden structure that is wired with twin and earth and no pipes and a ceiling with no access.
I have to remove wires, move db, and issue a coc on work done. My problem is that in half of the building, the Twin and Earth are clipped direct to the inside of the wall before it was clad. Solve the do not disturb the wires problem, but repair or replacement afterward is nearly impossible!
Also, the Twin and Earth go through holes in the wooden beams without protection.
Rewire is my first choice but accessibility is a problem and it will come at a cost.
But what about 6.4.6.2 where it says that it is ok if the wiring will not be disturbed?
Which is the best pipe and twin and earth or no pipe Also the one or two places where they used pipes no glands were used

**Derlyn** · 12-Aug-23, 04:51 PM

Originally Posted by Thys LOW Elektries

On the topic of Twin + E. I have a wooden structure that is wired with twin and earth and no pipes and a ceiling with no access.
I have to remove wires, move db, and issue a coc on work done. My problem is that in half of the building, the Twin and Earth are clipped direct to the inside of the wall before it was clad. Solve the do not disturb the wires problem, but repair or replacement afterward is nearly impossible!
Also, the Twin and Earth go through holes in the wooden beams without protection.
Rewire is my first choice but accessibility is a problem and it will come at a cost.
But what about 6.4.6.2 where it says that it is ok if the wiring will not be disturbed?
Which is the best pipe and twin and earth or no pipe Also the one or two places where they used pipes no glands were used

One does'nt need to have access to the wiring as long as there are no connections or terminations that are inaccessible.

Just about every flat roofed house that I've worked on has wiring that is not accessible.

**Thys LOW Elektries** · 13-Aug-23, 05:51 PM

The problem starts with me having to move the existing db that is under an open deck and the power trips every time it rains and the wind blows.
The CBI breakers have a white scale layer on them! Guess from getting wet through the years.
I have to join the existing electrical network somehow to the new db. I can open the walls but the ceiling part is not accessible Thinking of running trunking against the wall and running all the wires in it up to the surface mount db.
Will make sure the coc says I only work on the db!