Spot the error (Piccy)

[Lectrician]

This may be a tad hard to spot. We'll see...

Outside lighting control on a shop unit.

The white flex dropping down vertically on the left is from the DB, taken from an existing lighting MCB.

The right hand switch in the dual box is 'meant' to be the main isolation for the outside lights.

The right hand of the dual box (two gang switch) switches the front lights and the back lights. The timer is wired in between the switches.

The main isolator does not isolate as it should!

I turned off the main isolator, turned off the time clock, and turned off both switches on the two gang switch. The lights were off, but still very much live...

How? Nothing spurious, everything is in the pic!

 

[sparkwright]

Reversed polarity at the consumer unit, AND faulty double pole switch, breaking only one pole?

 

[knowall]

the 20A DP switch ! That switch is should be wired across the connections LL NN

KA

 

[EFLImpudence]

The right hand switch in the dual box is 'meant' to be the main isolation for the outside lights.

Assuming you mean left -

It's an intermediate.

 

[AndyPRK]

Oh well spotted ! if your correct !

 

[sparkwright]

I think he is...

 

[RF Lighting]

Terminals look too small for it to be a 20A DP, so must be an intermediate

There really are some muppets about

 

[AndyPRK]

Back box is screwed on well though. 4 screws!

 

[SimonH2]

It's an intermediate.

That's what I reckon too - and I decided that before reading any suggestions.
So when "Off" it merely switches L & N so when the timer and/or light switches are off, it is the neutral (now on the brown wire) that's disconnected.

 

[Lectrician]

The right hand switch in the dual box is 'meant' to be the main isolation for the outside lights.

Assuming you mean left -

It's an intermediate.

Yep, I meant Left.

It is indeed an intermediate! How you can confuse that I have no idea!

 

[EFLImpudence]

 

[SimonH2]

It is indeed an intermediate! How you can confuse that I have no idea!

You have to ask - it's got four terminals, so it must be the right one

 

[securespark]

FFS.....I've seen it all now....

 

[SimonH2]

I've seen it all now

I doubt it, each time you think that, someone will come up with something new