BM RCBO's

[fivestar]

Just fitted some BM RCBO's on a cu changeout. got some very strange results - i.e. 5 xI delta n times SLOWER than 1 x Also of the 7 units 3 were out of limits mostly on the 5 x test but 2 of these where ok at 1 x. Anyone else had weird results like this or have I just got a duff lot (brought of fleabay).

 

[Mr Mark Sparks]

hi
i had never heard of bm
now looked them up i guess you get what you pay for they are very cheap
the closest thing ive seen to your problem is some times a trip will be the same time at x1 and x5 but well within limits

 

[steamboatwilly]

Never used BM but did get this same problem a few weeks back with a Hager RCBO.

 

[Christech]

As with all RCBO's you heve to check with the manufacturer the correct way of testing .
The RCD side of the device incorporates a CT that sometimes if testing on terminal screws bypasses this CT and gives wrong readings.

 

[andekoch]

Generally best to test RCBO's at a point on the circuit some distance away from the board/ RCBO to get the most reliable results.

 

[Christech]

Doing a "Full Functional Test" at the RCBO eliminates that the device and may i quote "Cheap" is working correctly IEC61009 . If this is the case then it is a cicuit problem that needs to be sorted and very quickly.