New consumer unit ?

[JohnW2]

I agree it should be the right way up, but why is it incorrect for the isolator to up off? (Generally, not just this situation). ...

I can't remember whether any regs actually say/require this (I'll have a look when I have a moment) but I thought the 'general thinking/wisdom was that isolators etc. should be "down = OFF", so that if something were to fall onto the lever (knocking it down) it would 'fail safe'.

Kind Regards,

 

[JohnW2]

My best guess, would be that the live side should go to the smallest amount of metal possible for safety, in case the switch suffer physical damage.

Yes, I think that's one of the arguments I've heard "in that direction" (i.e. suggesting that supply should go to the fixed contacts) but I can't remember what the arguments were 'in the other direction'.

Of course, switch designs vary a lot. It's quite common for both 'in' and 'out' ('supply and load') to be 'fixed contacts, with the only moving part being a bit of metal that connects the two fixed contacts in the "on" state. Such a design is totally symmetrical, so it wouldn't matter a jot which way around it was used.

For what it's worth, when we draw schematic diagrams, we almost invariably show supply connected to the 'moving contact'.

Kind Regards, John

 

[SUNRAY]

I can't remember whether any regs actually say/require this (I'll have a look when I have a moment) but I thought the 'general thinking/wisdom was that isolators etc. should be "down = OFF", so that if something were to fall onto the lever (knocking it down) it would 'fail safe'.

Kind Regards,

I believe the only detailed isolator in the regs is petrol stations, where it is specified as up = off

 

[ericmark]

The standard with a switch or isolator is to mount so anything that falls on it switches it off. However with domestic light switches and sockets it seems down is on, which is against standard safety rules, but type of switch is unlikely to be knocked on by something falling so does not really matter.

I had a German distribution unit where the MCB or RCBO was on its side, and the design was so MCB off to right and RCBO off to left.

Some consumer units have two RCD's one with line to left and one line to right, and both line and neutral are live so question is does it matter?

I have come to fit sockets on a second fix, first 4 boxes line to left then last box line to right, and yes got it wrong as a result, but found when inspecting and testing, and this is the point, to both get line and neutral swapped, and miss it when inspecting and testing is very unlikely. Getting phase rotation wrong yes, I may have a phase rotation meter but many don't but testing line and neutral seems very unlikely to get it wrong twice once when installing and again when testing.

 

[JohnW2]

I believe the only detailed isolator in the regs is petrol stations, where it is specified as up = off

I've had a quick search and (as I suspected) it seems that BS7671 is totally silent on this issue.

However, as I (and eric) have said, I think that many/most people feel that "down = OFF" is somewhat ;safer';.

Kind Regards, John

 

[JohnW2]

Some consumer units have two RCD's one with line to left and one line to right, and both line and neutral are live so question is does it matter?

I see no reason why it should make any difference 'which way around' the L and N are conncted to an RCD.

Kind Regards, John

 

[plugwash]

AIUI oldschool british gear was/is up=off, IEC gear is down=off

 

[EFLImpudence]

In the original post with the switch upside down and in the down/on position, the switch say 'NO'.

How much clearer could it be?

 

[JohnW2]

In the original post with the switch upside down and in the down/on position, the switch say 'NO'. How much clearer could it be?

However, as I said, I believe the usual thinking is not about 'how clear it is' but, rather, what happens if (as in OP's) the (upside down) switch is in an 'up = off' position and something falls on the lever to push it down into the 'on' position.

Kind Regards, John

 

[EFLImpudence]

Sounds logical - but how many places have the on position down?

Is it the usual British situation of solving a problem it has unnecessarily caused - like the UK plug?


Here - the light switches are up for on as they are in the US.