NSX 630N Trip adjustment

[ChrisMcC]

It is possible to adjust the trip level of the MCCB while live without risk of false trip? Thanks

[Gregoire_Brun]

hello @ChrisMcC 

first question is:

Why did you want to change setting? 

Because most of them were determined by the global study of the panel and to touch them could reduce some protection levels.

Nevertheless, if it really needed, if you increase values (tripping level) less risk of nuisance tripping (but you reduce your protection level).

If you decrease values of tripping value, it should be possible to pass to the over side of the slide…

So take care of you during this manipulation, use your security equipment for your safety.

[ChrisMcC]

Hi Gregoire, thank you for the reply. The breaker was initially set 400A, it's safe to raise it 630A, all downstream cabling/equipment is rated. It was decided to do this due to some peak loading coming close to 400A. I'd like to do this without taking plant the down (adjusting while still on), my concern is the potential for a false trip while the adjustment is being made. 

Thanks

Chris

[Gregoire_Brun]

@ChrisMcC on this case to risk of false tripping, but be carfull to double check size equipment because in many time with compact NSX 630A , inside equipment, some derating need to be apply . 

Double check that inside your equipement, enviromental temperature wasn't higher than 40°C. 

a setting at 570A should be more secure....

[ChrisMcC]

Thanks again Gregoire, is it possible to adjust upwards while live without risk of tripping? I believe it was issue on older breakers.

Thanks

Chris 

[Gregoire_Brun]

No problem @ChrisMcC 

if you turn normaly the rotary switch , it should be ok. don't turn slowly

br

[ChrisMcC]

Thanks, much appreciated