hellooo from london

[Rundiz]

now i have a question that will test one of you

i have a number of dorman smith 32a type b rcbos in one of the buildings where i work, they are in the off position however there is still power out the load side the switch will not stay up at all.
ive put it down to the rcbo defective but ive never seen anything like this before so i thought ide try get a little insight from any of you guy

thanks

 

[Marvo]

Backfed from a UPS? Crossed circuit with another DB? Did you disconnect the load wiring and test again?

 

[telectrix]

i've had MCBs fried so that they won't switch off.

 

[Guest77]

As Marvo mentioned, Is there a supply on the load wiring when it is disconnected from the OCPD?

 

[Rundiz]

i havnt been able to disconnect or do any testing yet as theres computers on theses circuits so im waiting for the rcbos before we do any of that and i cant see there being any back feed this buildings newly refurbished however i am concerned that the equipment there using on these circuits may be causing the issue as they are labs doing secret stuff lol, all will be revealed soon enough i guess. ive also recomended to split there loads up so there hubs are on seperate circuit

 

[Besoeker]

i havnt been able to disconnect or do any testing yet as theres computers on theses circuits so.......

...so not impossible that some computer system user has a back up UPS?

 

[Rundiz]

just done a bit of research on ups backfeed seems like thats the only explanation that makes sence cant wait to test it

thanks guy appreciate the help

 

[Marvo]

Watch your fingers when you test, assume every wire could become live at any time. This is one of those issues that could easily result in you getting an unexpected whack off something.

 

[Rundiz]

thought ide open this again after investigating this problem there was no back feed from ups the rcbos would not trip under any test and after opening one up up the contacts were welded any thoughts has anyone seen this before just to mention there were 3 rcbos in question