1.5mm circuit 1mm switched drops

[bugsy]

Went to a job today ( domestic ) checking through the installation ( which has recently been rewired ) I noticed that the lighting was 1.5mm but the switch drops were 1mm anyone seen this before?

 

[bugsy]

It's a mis-conception that Tri-rated has a higher current rating; the cable actually to conforms to three different standards. These standards are:
1. BS6231 ~ (UK)
2. UL Subject 758 Appliance Wiring Materials (AWM) ~ (USA)
3. Canadian Standards Association (CSA) approved.

Hence the name --tri rated

 

[bugsy]

exactly i got pulled for using the old tubes on my first NIC inspection. He went into the loft just to inspect if we'd used them. had a right go at me - still passed though.
Still save the old grommets though

What reason did he give you for having a go?

 

[pennywise]

Think because he didn't earth the tubes or put end grommets on the tops of the drops sorry if I got that wrong. It is suppose to be earthed metalic conduit regardless of new or old technically.

 

[bugsy]

agree with the grommets but if it's a rewire or new install the circuit involved woulld be protected by an rcd/rcbo so why earth the conduit

 

[dixon9]

Went to a job today ( domestic ) checking through the installation ( which has recently been rewired ) I noticed that the lighting was 1.5mm but the switch drops were 1mm anyone seen this before?

The circuit would therefore be considered as wired in 1mm (the "weakest" point of the circuit) and current carrying capacity would be calculated on that basis.

The installer would have effectively wasted metres of 1.5mm on the lighting runs.

 

[GT1]

my lecturer on my course said he always used 1mm singles for the switched drops.
He said it was part cost, part helps to tell the cable apart..!
in fact my house is wired that way come to think of it..

 

[Davey101]

The circuit would therefore be considered as wired in 1mm (the "weakest" point of the circuit) and current carrying capacity would be calculated on that basis.

The installer would have effectively wasted metres of 1.5mm on the lighting runs.

Agreed. Seems a stupid idea to me, why not just wire it all in 1.0mm?

 

[bugsy]

my lecturer on my course said he always used 1mm singles for the switched drops.
He said it was part cost, part helps to tell the cable apart..!
in fact my house is wired that way come to think of it..

How old is your lecturer?, did he also use wooden channel?

 

[pmac10]

It's a mis-conception that Tri-rated has a higher current rating; the cable actually to conforms to three different standards. These standards are:
1. BS6231 ~ (UK)
2. UL Subject 758 Appliance Wiring Materials (AWM) ~ (USA)
3. Canadian Standards Association (CSA) approved.

i knew why it was called tri rated, but had also been told it had a higher current rating,
we live and learn.

 

[DurhamSparky]

my house is wired like that!! only noticed when i went to drop a 2 way circuit in back of switch 1.5 3core for bedroom as im lazy!!