When working on circuits do you isolate whole board or just the final circuits using MCBs ?

[newlearner]

When working on circuits do you isolate whole board or just the final circuits using MCBs ? Or is there any instances when the whole board has to be isolated even if you are working on few final circuits?

Thanks.

 

[newlearner]

Thanks all for your valid points. It's interesting to read.

As a lot of you have pointed out better safe than sorry and yes probably qualified electricians would be better suited.

 

[telectrix]

some older boards have exposed live parts and these would definitely be considered to be unsafe to work on unless isolated. more recent boards are safer inasmuch as all live parts are covered/insulated, so horses for courses. RA first, then decision. it's your life.