Dinner time Q & A session

[sparrow eye]

A couple of months ago, between dunking rich teas and listening to Jeremy Vine, myself and a few other sparks got debating the following:

1. Why is 1.5 the cable of choice for most lighting circuits when, in most domestic settings, small offices, or even larger settings where the DB has enough ways and the circuits are split sensibly; 1mm would be adequate?

2. When installing in trunking (and I'm thinking plastic, compartmental here), and you are using 2.5 T&E, we are happy that the earth is 1.5. Yet we wire the same ring in 2.5 singles and use a 2.5 earth? Why not opt for the smaller third cable?

3. As the CPC can become live under fault conditions why is it not insulated green and yellow at the manufacturing stage when producing twin and earth cable?

I'm not being stupid here. We put the world to rights on all three issues and came up with numerous answers. I'm not going to tell you what they were though! Answers on a postcard please. And there's extra marks for showing workings out.

 

[Sparky Ninja]

I'm not going to tell you what they were though!

Well I'm not going to tell you my answers either.. ner ner.

:30:

 

[Deleted member 26818]

1 don't know.
2 the minimum CSA for a protective conductor, not part of a cable, is 2.5mm².
3 it's cheaper to produce like that, and protective conductors don't have to be insulated.

 

[sparrow eye]

Ok. I'll share.... soon!

 

[Geoffsd]

1: fashion
2: as spinlondon
3: as GLENNSPARK

 

[diditrain]

For number 1, when i was at college my tutor did some calculations and found that the 1.5 was more economical in the long run despite the initial higher purchase cost. Can`t remember the exact in`s and out`s of it though

 

[Deleted member 9648]

A couple of months ago, between dunking rich teas and listening to Jeremy Vine, myself and a few other sparks got debating the following:

1. Why is 1.5 the cable of choice for most lighting circuits when, in most domestic settings, small offices, or even larger settings where the DB has enough ways and the circuits are split sensibly; 1mm would be adequate?...cos it's more likely you will by chance comply with the volt drop for lighting even if you dont know how to work it out.

2. When installing in trunking (and I'm thinking plastic, compartmental here), and you are using 2.5 T&E, we are happy that the earth is 1.5. Yet we wire the same ring in 2.5 singles and use a 2.5 earth? Why not opt for the smaller third cable?..I use 1.5 cpc's when installing trunking systems.....so not a question I can answer

3. As the CPC can become live under fault conditions why is it not insulated green and yellow at the manufacturing stage when producing twin and earth cable?..Dont know,dont care.....it just is....

I'm not being stupid here. We put the world to rights on all three issues and came up with numerous answers. I'm not going to tell you what they were though! Answers on a postcard please. And there's extra marks for showing workings out.

..Workings out?....what are they?..

 

[ezzzekiel]

dont know but.
1. is there life after death
2. do aliens exist
3. why am i up at this time

 

[telectrix]

dont know but.
1. is there life after death
2. do aliens exist
3. why am i up at this time

1. i'll tell youif there is if i find it when i die.
2. course they do. where do you think the IET comes from.
3. wet the bed?

 

[Electro-tech]

For number 1, when i was at college my tutor did some calculations and found that the 1.5 was more economical in the long run despite the initial higher purchase cost. Can`t remember the exact in`s and out`s of it though

Cables now available on Higher purchase !:clown: