Crossing ceiling joists with lighting cable
 

Hi

I'm sure this is an obvious question but... when rewiring the lighting
up in the roof space, where should I run the cabling? I was intending
to clip it to the sides of the joists whereever possible, just below
the top edge, meaning that it won't get damaged by any temporary
boards I may put down for access; yet will remain more or less visible
and not buried under Rockwool - OK?

How about when I need to cross the joists at 90 deg, though? Or
should I just never do that, and always go the long way round,
parallel to the joists? (I've never seen that done in any place I've
lived, but especially as I'm going to get inspected eventually, I
figure I need to do this by the book). If I can cross joists, should
it be on fixed supporting battens or something? And presumably above
the Rockwool, which isn't in place yet? The current wiring I'm
removing crosses joists everywhere, clipped in places so you could put
your whole weight on a cable between two joists if you weren't
careful.

BTW is it a 'requirement' to physically remove any old cables when you
do a rewire?)

Thanks
David

Crossing ceiling joists with lighting cable
 

Lobster wrote:

I'm sure this is an obvious question but... when rewiring the lighting
up in the roof space, where should I run the cabling? I was intending
to clip it to the sides of the joists whereever possible, just below
the top edge, meaning that it won't get damaged by any temporary
boards I may put down for access; yet will remain more or less visible
and not buried under Rockwool - OK?

Sounds good so far....

How about when I need to cross the joists at 90 deg, though? Or
should I just never do that, and always go the long way round,

Normal practice in the loft is to cross them as and when you need. If
you are planning to lay boards over the cables then you either need to
drill holes in the sides of the joists (probably not worth the hassle),
or notch the top of the joists. Personally I did the latter when I
boarded my loft a few years ago. A router with a half inch bit is ideal
for making small channels in the joists. A handy tip is to mark on the
boards where the wires cross so you don't get carried away when
screwing/nailing them down.

figure I need to do this by the book). If I can cross joists, should
it be on fixed supporting battens or something? And presumably above

Nope - joists are usually 400mm or less apart - not a problem span for
ordinary T&E cable.

BTW is it a 'requirement' to physically remove any old cables when you
do a rewire?)

Don't think it is a requirement - especially when you think that many
cables might be buried in plaster etc. It would be worth while removing
as many as you can without causing much extra work though, simply to
avoid the confusion of having lots of extra wires about and not knowing
which are live!

--
Cheers,

John.

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\================================================= ================/

Crossing ceiling joists with lighting cable
 

Normal practice in the loft is to cross them as and when you need. If
you are planning to lay boards over the cables then you either need to
drill holes in the sides of the joists (probably not worth the hassle),
or notch the top of the joists.

Notching is now frowned upon. Drilling is supposed to be the answer,
although ceiling joists may be too thin even to allow proper drilling away
from the edges.

Christian.

Crossing ceiling joists with lighting cable
 

John Rumm wrote:

BTW is it a 'requirement' to physically remove any old cables when you
do a rewire?)

Don't think it is a requirement - especially when you think that many
cables might be buried in plaster etc. It would be worth while removing
as many as you can without causing much extra work though, simply to
avoid the confusion of having lots of extra wires about and not knowing
which are live!

In some ways it'd be a good idea to make it a requirement having played
in the loft of my new place - picking up a half buried length of cable
from the insulation to find you're holding a couple of bare ends while
balanced on a joist is always fun.... ;-)

And then there's the length of cable that's dead & disconnected at one
end yet still plumbed into a fully connect junction box at the other...

--
Scott

Where are we going and why am I in this handbasket?

Crossing ceiling joists with lighting cable
 

On 19 Feb 2004 06:39:18 -0800,
(Lobster) wrote:

Hi

I'm sure this is an obvious question but... when rewiring the lighting
up in the roof space, where should I run the cabling? I was intending
to clip it to the sides of the joists whereever possible, just below
the top edge, meaning that it won't get damaged by any temporary
boards I may put down for access; yet will remain more or less visible
and not buried under Rockwool - OK?

Sounds fine.

How about when I need to cross the joists at 90 deg, though? Or
should I just never do that, and always go the long way round,
parallel to the joists? (I've never seen that done in any place I've
lived, but especially as I'm going to get inspected eventually, I
figure I need to do this by the book). If I can cross joists, should
it be on fixed supporting battens or something? And presumably above
the Rockwool, which isn't in place yet? The current wiring I'm
removing crosses joists everywhere, clipped in places so you could put
your whole weight on a cable between two joists if you weren't
careful.

The usual way is to run on the side of the joist to the nearest
batten\stringer or whatever crosses the joists at 90 degrees and
follow that along to wherever you need the cable to go.

BTW is it a 'requirement' to physically remove any old cables when you
do a rewire?)

I don't think so, it does make it easier to remove what you can see
though.
...

SJW
A.C.S. Ltd.