Dis Board query

have to wait until we open it up, but compared to the schneider 3ph boards, the RCBOs are upside down.

Just looked at a current Hagar TP board with a mix of TP and SP MCBs and RCBOs. On is to the outside Off to the inside. If the board in the OP is a Hagar, I have worked on what look like similarly aged Hagar boards and the BB is down the centre and old/new MCBs/RCBOs fit them with On to the outside.


These days I am usually confused about everything so I always have to look to see what is on/off and get very confused by some things where pressing red is off and green is on and then others where green is off. If there is a standard about such things it has passed me by.  ? (Confused face!)

maybe its that the breakers have been redesigned. The RCBOs are new compared to the board. It is a Hager, and I just noticed the sticker on it that shows on, as being towards the middle.

I suspect its the following. In the Good Old Days (tm) only MCBs were intended to go in that DB. Assuming that the MCBs can mechanically/electrically be connected either way round, then which way round to put them is completely arbitrary, and so it comes down to an aesthetic decision the DB manufacturer made when they stuck 'on/off' labels on the front of the DB. That manufacturer happened to choose 'on' being towards the central spine.


However, RCBOs aren't bidirectional; they typically have a bus bar termninal at one end, and 3+ connections at the other end (2 terminals, a N flying lead, maybe a FE) so the base has to go towards the bus bar. So in newer boards the manufacturer sticks the 'on/off' label with off outwards for consistency.

If they have been fitted backwards, they might not fit quite as properly as they should do when installed correctly. If you need to remove any breakers just make sure that the whole board is isolated.


I've seen it before where the board couldn't be isolated and an electrician had to remove a breaker that was installed the wrong way around... the breaker dropped slightly and crossed the phases.


No one was hurt but it did make one hell of a bang and blow the main fuse in the LV chamber in the basement!

HA ! even if the breakers are symmetric and can be fitted both ways, it does not really mean it is a good idea to do so.

I'd suggest that to avoid mistakes of thinking things are off when they are on, then they should be turned to face the same way on any given side, outward is on seems to be the modern trend, as upward is on. The regs do require clear labeling of switchgear to avoid errors, and I;d put this in the same class.

I'd not be worried about a mix and match of MCB and RCBO particularly, or units of varying age, so long as they fit on the rail and connect well to the bus bar (as some makers seem to have changed their terminal reference plane between models so a good fit is not guaranteed)  but I think user uncertainty about the on/off direction could quite easily cause an accident.

On is normally up these days and the writing shows which way is up.


I agree with the above: it is unlikely that the RCBOs could have been put in the wrong way round, so it is the MCBs which are upside-down.


I cannot go above C3 for the MCBs because there seem to be 2+ faults to danger. However, confusion about isolation is IMHO a significant risk which ought to be remedied.


(Outward is on in Eaton TPN boards.)

i think the confusion is an issue, because when something trips, inevitably, someone goes and pushes every breaker up, turning all sorts off!