No functional Earth on RCBO

[PeatBog]

I bought a Contactum RCBO today. When I got home I was surprised that there was no functional earth cable, I assumed that it was damaged and the earth had simply pulled out. However, it looked identical to a BM one that I had in stock which does have a functional earth cable. When I compared the two schematics that are printed on them then i noticed the Contactum one didn't have a functional earth shown. So is this correct??

Every other RCBO I have ever seen has had a functional earth!!!

Not much technical info available on the Contactum website these days

 

[Andy™]

i think its so the RCBO can detect loss of neutral and still trip. RCDs dont have it, so it follows the RCBO's dont have to have them

 

[Evans Electric]

Thats interesting , I don't have an answer, although a standard RCD has no reference earth tail , still works. In fact it raises the question , why do RCBOs have an earth tail in the first place. I sit back and await the flood of answers.

 

[batty]

I think its the design of how it works although not an expert. Mem electronic Rcd's and Rcbo's do have the leads. I fitted two contactum yesterday they where the old type they had no earth cable and worked perfectly also the new type don't have one either so yours are not faulty. Maybe they are not electronic I am only guessing though.

Batty

 

[electrizion]

Not sure about Contactum but Merlin Gerin when asked said

"The "functional earth" flying lead is the earth reference required in order to detect lost supply neutral; without this flying lead, the RCBO will not (adequately?) detect earth leakage unless the supply neutral is intact."

 

[steptoe]

AH HA gentlemen, we may have found that elusive DP RCBO.

as is with an RCD, it somply detects an imbalance between L-N, and therefore assumes it to be a leakage to earth, without having to resort to an earth reference point.

could you check if it is actually a DP RCBO,

 

[batty]

AH HA gentlemen, we may have found that elusive DP RCBO.as is with an RCD, it somply detects an imbalance between L-N, and therefore assumes it to be a leakage to earth, without having to resort to an earth reference point.

could you check if it is actually a DP RCBO,

Sorry steps the single module contactum ones have a solid neutral tested it with switch down neutral is still conected. The two module ones they used to sell are dp though.

Batty

 

[steptoe]

Sorry steps the single module contactum ones have a solid neutral tested it with switch down neutral is still conected. The two module ones they used to sell are dp though.Batty

oh well, that is that theory f##ked then.....

 

[batty]

oh well, that is that theory f##ked then.....

Not sure how they work never took one apart but but I always thought the ones with flying leads where electronic and the ones without where mechanical but who knows I only fit and test them.

Batty