Switch on a Hager BS4293 RCCB?

[richy3333]

Hi All.
I've been undertaking a PIR/EICR and the property has a load of old Hager BS4229 RCCBs on various boards. Can anyone tell me if this is a switch on a Hager BS4293 RCCB and if so, what it is for? I've spoken to Hager and sent them the photo and they don't know?! The switch is to the right of the 0/off position:

 

[Engineer54]

The first “sensitive” E/L unit I fitted was a 3ph 60A 500mA unit. It was the size of a house brick!
My first house had two Crabtree 60A 500mA units feeding two Wylex 8 way boards, it was that modern! But it was bang up to date for it’s time. That was the 13/14[SUP]th[/SUP] edition, I can’t remember which.

Very few current operated devices about during the 13th ed, it would have to have been mid to late 14th ed. Don't even think the voltage operated devices were covered in the 13th, though possibly may have been in the last revision. I think it wasn't until maybe midway through the 14th that both current and voltage operated units were included... Memory is a strange thing as the years pass, so i may well be well out here...lol!!

I can only remember seeing any earth fault protection on switchboards, can't ever remember seeing RCD's installed in the industrial setting that i was in. Though they may have been incorporated on one or two of the newer bit of equipment that was continually being brought in. Just can't remember seeing them... lol!!

 

[richy3333]

Many thanks for the useful information Eng54 and Tony. As I think I said I came across the unit(s) on a recent PIR. I think it is a switch also, but try as I might I can not get it to budge. The building is full of these 100mA and 300mA units and I thought it funny that Hager couldn't tell me what it was for! Lots of rectification work required so maybe I'll get to play around with it some more if I get the remedials.

Thanks again.

Richard

 

[Rampage]

Looks like it's something that pops out into the back of the rotary switch to lock it off maybe?

Is there an indentation in the back of the rotary switch?

If it was an indicator wouldn't it be within the radius of the indicator hole?!