appropriate wiring

[mrcrow]

i am going to fit an outside lamp to my garage, not one with a sensor, and control it from a weather proof switch with a neon
this is so when i drive in at night i can flick the lamp on to see the lock for the garage door and illuminate the drive and back gate area
i plan to make the supply via a 13amp plug from a socket inside near the door.
the holes in the switch and lamp holder to take the wiring are pretty small.
the bulb is a 42w halogen (55w equivalent)

what would be the correct cable to use?

cheers
Geof

 

[ban-all-sheds]

i plan to make the supply via a 13amp plug from a socket inside near the door.

That is a really tacky, ugly bodge.

what would be the correct cable to use?

One large enough for the load, given how it's installed and how long it is, and with the right mechanical properties for the environment (impact damage risks, weather exposure, etc)

• http://www.google.co.uk/search?q=cable+installation+methods+17th+edition
  
  
• [wiki]Electrics%3AMCBtoCable[/wiki]
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://web.archive.org/web/20070327014113/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.batt.co.uk/upload/files/4d5.pdf
  
  The references above which are in italics are out of date. The principles are still valid, and you can absolutely learn valid things from them, but you will need to refer to the latest edition of the Wiring Regulations to get the correct data.

 

[mrcrow]

i plan to make the supply via a 13amp plug from a socket inside near the door.

That is a really tacky, ugly bodge.

what would be the correct cable to use?

One large enough for the load, given how it's installed and how long it is, and with the right mechanical properties for the environment (impact damage risks, weather exposure, etc)

• http://www.google.co.uk/search?q=cable+installation+methods+17th+edition
  
• [wiki]Electrics%3AMCBtoCable[/wiki]
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
• http://web.archive.org/web/20070327014113/http://www.kevinboone.com/cableselection_web.pdf
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
• http://www.batt.co.uk/upload/files/4d5.pdf
  
  The references above which are in italics are out of date. The principles are still valid, and you can absolutely learn valid things from them, but you will need to refer to the latest edition of the Wiring Regulations to get the correct data.

thanks old chap,
would 1.0 T&E in surface ducting would hold most of the load and not overheat?
the run of cable from source to the lamp is 1.2 m
not sure that 1.5 will go into the lamp or switch terminals
the wiring for the switch and lamp come through from the inside of the garage via two holes i bored in the blockwork so those are inside along with the supply and would be sealed on the outer end as they pass directly into the switch and the lamp holder
the cables would then be connected inside the garage via a 3 connector single blocks inside a weatherproof junction box
the idea of the plug/socket connection is that i would only need this lighting in winter and may need both the twin sockets spring to autumn as i live in cornwall where the sun never sets it just gets dull in the winter
i have trunking to protect the cable inside the garage and the cable is at 1.5m above floor level
i would ascertain the load is 60W at 240v being around 0.25 amp on a 3 amp plug fuse

i appreciate your first comment and i take it that is a professional one and the welcome piece of advice with those links
cheers
geof..

 

[ericmark]

Outside use a black cable as less effected by sun light also use a round cable as stuffing glands will seal better on it. Personally I like a cool light for out side as any hot light will expand any air in the fitting then suck in any water as it cools down again with that looking at some where around 7W so 1mm² is likely ample.

 

[sparkwright]

If you insist on supplying all this by a 13 amp plug plugged into a 13 amp socket then you need 3 core round FLEX, 0.75 or 1.0 mm2 would be a typical size.

 

[mrcrow]

Outside use a black cable as less effected by sun light also use a round cable as stuffing glands will seal better on it. Personally I like a cool light for out side as any hot light will expand any air in the fitting then suck in any water as it cools down again with that looking at some where around 7W so 1mm² is likely ample.

"sparkright,....If you insist on supplying all this by a 13 amp plug plugged into a 13 amp socket then you need 3 core round FLEX, 0.75 or 1.0 mm2 would be a typical size

thanks ericmark and sparkright
i have some black round cable from my past work on industrial sites used for inspection lamps but its 2 core with a string thread through it. the insulation is red and black for live and neutral and i got it in 1960 when i was an apprentice in the shipyards...its not rusty or anything and is probably proper copper wiring...

there is no earth point on the switch as it is all plastic and i think the lamp may be the same
i got them from toolstation and didnt cost much..they are plastic

both cheapie "amateur stuff" i know but they are rated accordingly

i can fit round core cable black or white as the wiring is inside the garage ..my local "shed" has some by the metre..:;

its just where to connect the earths to?? there wont be any continuity over the installation
chock and block or two core??

i can say i have some really good advice here and appreciate all who have helped me

cheers
geof

 

[Iggifer]

Chocbloc all the way. You a) need an earth in every piece of LV fixed wiring and b) may at some point, change the fitting for one that requires and earth, and then you'll have to go back and reconnect them all.

Don't use two core red and black flex! Throw that stuff in the bin and spend £5 buying some new 3 core stuff

 

[mrcrow]

Chocbloc all the way. You a) need an earth in every piece of LV fixed wiring and b) may at some point, change the fitting for one that requires and earth, and then you'll have to go back and reconnect them all.

Don't use two core red and black flex! Throw that stuff in the bin and spend £5 buying some new 3 core stuff

yes i will get some new stuff and your point about chocbloc makes sense...cater for the future
many thanks for that
its not a problem to that since i will use a junction box and only need 3 of the 4 connector points for the live and neutral wiring...i can put all the earths in the spare way and block them in the switch casing and lamp housing
how is it black and decker tools get away with two core orange cable for outside use?
i am only interested and wont be using any of it even though i have a heap of it
time for a clear out and say no! to cutting corners
cheers
and thanks again all
geof

 

[ban-all-sheds]

how is it black and decker tools get away with two core orange cable for outside use?

That's not fixed wiring

 

[Iggifer]

From a flex it's different rules. But they will be double insulated, simply that means there is an extra layer of insulating material between the live parts and the casing. Look for a little symbol of a square inside a square, that means it needs only live & neutral, and the plug may even have a plastic earth pin

 

[mrcrow]

how is it black and decker tools get away with two core orange cable for outside use?

That's not fixed wiring

thanks old chap
i did use it for loft lighting wiring which wasnt fixed either just looped over a couple of roof trusses...it also was connected by a plug to a wall socket in the hall and removed after use
cheers
geof

 

[mrcrow]

From a flex it's different rules. But they will be double insulated, simply that means there is an extra layer of insulating material between the live parts and the casing. Look for a little symbol of a square inside a square, that means it needs only live & neutral, and the plug may even have a plastic earth pin

thanks
thats a very understandible reason seeing there is a bit of moisture around sometimes when cutting grass
cheers
geof

 

[TonyW2]

Only out of interest, why does cable suited for non fixed use become unsuitable if it is clipped into place?

 

[mrcrow]

Only out of interest, why does cable suited for non fixed use become unsuitable if it is clipped into place?

ban all sheds will answer
i think its something to do with temperature??

 

[ban-all-sheds]

i did use it for loft lighting wiring which wasnt fixed either just looped over a couple of roof trusses...it also was connected by a plug to a wall socket in the hall and removed after use

Sounds like that might have counted as fixed wiring.