Passing another circuit through back box

[Raptor0014]

Had a bit of a ‘discussion’ today with another electrician.

Basically found a light switch in which the radial cable for a socket directly below (but about 3ft lower) passed through.

Other electrician said it was wrong and shouldn’t be done.

My take was that it is, at best, a bit of bad design during the 1st fix. But other than that it kept the cable within the cable zone.

He argued that if the back box ever had to be replaced you’d have to cut the cable to the socket. To which I highlighted my point about bad design but that’s it.

To me it’s safe, cable is protected, it doesn’t interfere with the circuits for the lights (it was a 35mm back box) and it kept the cable within the prescribed cable zones.

He was adamant that it was wrong. I disagreed. He said it breached regs as you can’t have circuits feeding other accessories passing through.

So I asked what regulation it breached and why it was wrong. At this point the discussion ended as he couldn’t find the regulation in the ‘good book’ or OSG.

So, as I am always prepared to eat humble pie and admit if I’m wrong, does it breach any regulation to pass a seperate circuit through the back box of one accessory to feed another accessory? If so can someone let me know which regulation is contravened by doing so.

Thanks.

 

[James]

There is nothing wrong with what you described above.
let’s face it, trunking work will provide sockets and switches with 20 other circuits running through behind.

 

[brianmoooore]

Like you said, not brilliant design, but completely within the regs

 

[Raptor0014]

There is nothing wrong with what you described above.
let’s face it, trunking work will provide sockets and switches with 20 other circuits running through behind.

I mentioned that sort of scenario to him. But he tried to palm that off as trunking being designed for the purpose where a back box is designed to house the accessory to control the circuits fed into it.

I could sort of see his thought process but he couldn’t give me any reason as to why it was dangerous or a regulation it breached.

Just thought I’d ask on here to make sure I’m not being dumb, for a change!

 

[James]

I mentioned that sort of scenario to him. But he tried to palm that off as trunking being designed for the purpose where a back box is designed to house the accessory to control the circuits fed into it.

I could sort of see his thought process but he couldn’t give me any reason as to why it was dangerous or a regulation it breached.

Just thought I’d ask on here to make sure I’m not being dumb, for a change!

Not dumb, if someone can’t quote you a valid reg that you are breaking, they are probably wrong.

 

[Vortigern]

There is mention of physical separation in the regs. I cannot see anything which specifically addresses such a scenario. I looked at 234 separation items. There is talk about not having differing circuits with exposed lives in the same enclosures but there seems to be provision for that even. Not an ideal scenario but I am sure I have done it maybe once at least. Don't tell anyone though.

 

[Dustydazzler]

I personally don't like other cables being passed through the back of a back box but its not the end of the world

 

[IAmSparkytus!]

More of an issue if it's a 3phase system and the 2 circuits were on different phases allowing 400V at the box

 

[timhoward]

As @ToonySparky said the only reg that comes to mind is requiring a warning label if there is more than one phase in the same enclosure. I've been meaning to check that one in A2.....

 

[westward10]

More of an issue if it's a 3phase system and the 2 circuits were on different phases allowing 400V at the box

Not required and hasn't been for a number of years.

 

[timhoward]

Not required and hasn't been for a number of years.

Thank you. Section 514 re-read. One day it will sink in....

 

[ipf]

I think a good example of this is a conduit with more than one circuit involving, say, a RFC and a lighting circuit with the lighting cables running through a socket to a switch. Nothing wrong with it, it's all enclosed in a conduit system....but maybe better done with a T box and one box either side.

 

[IAmSparkytus!]

Not required and hasn't been for a number of years.

Whats not required?

 

[Lister1987]

559.5.3 is the only mention of through wiring through what could be deemed an accessory (luminaire) that I can see, inversely I can't be one forbidding it either; unless you use the 134.1.1 workmanship, even then it'd be a battle to justify (unlabelled cables running through the accessories would be the justification), I wouldn't code if they were labelled and running through an accessory it did not serve, but I'd still record in the 'condition of install'.

 

[GBDamo]

Had a bit of a ‘discussion’ today with another electrician.

Basically found a light switch in which the radial cable for a socket directly below (but about 3ft lower) passed through.

Other electrician said it was wrong and shouldn’t be done.

My take was that it is, at best, a bit of bad design during the 1st fix. But other than that it kept the cable within the cable zone.

He argued that if the back box ever had to be replaced you’d have to cut the cable to the socket. To which I highlighted my point about bad design but that’s it.

To me it’s safe, cable is protected, it doesn’t interfere with the circuits for the lights (it was a 35mm back box) and it kept the cable within the prescribed cable zones.

He was adamant that it was wrong. I disagreed. He said it breached regs as you can’t have circuits feeding other accessories passing through.

So I asked what regulation it breached and why it was wrong. At this point the discussion ended as he couldn’t find the regulation in the ‘good book’ or OSG.

So, as I am always prepared to eat humble pie and admit if I’m wrong, does it breach any regulation to pass a seperate circuit through the back box of one accessory to feed another accessory? If so can someone let me know which regulation is contravened by doing so.

Thanks.

A case of someone trying to make the regs fit their personal taste.