On Load v Off Load

[lady electric]

Am i right in saying that off load switches break the neutral and line feed, and on load switches just break the line?

doing my 2330 303 exam on tuesday!!

 

[lady electric]

and also why do the continuity tests have to be done first - is it because it is the most common to have a fault there? so process of elimination or is there a scientific reason?
Thanks in advance

 

[cagedanimal2010]

An on-load switch can be switched while there is a load present for example a light switch, an off-load switch should only be switched when there is no load, for example a 3phase isolator on a motor circuit.
continuity of cpcs is done 1st to check just that, if there was a break in the cpc and you powered up straight away there is a potential danger, the cpc is the protection of the circuit, so if its not there, you may be putting your or someone else's life in danger.

Danny

 

[lady electric]

An on-load switch can be switched while there is a load present for example a light switch, an off-load switch should only be switched when there is no load, for example a 3phase isolator on a motor circuit.
continuity of cpcs is done 1st to check just that, if there was a break in the cpc and you powered up straight away there is a potential danger, the cpc is the protection of the circuit, so if its not there, you may be putting your or someone else's life in danger.

Danny

thanks for replying - just one thing though - Why is it before say the ~IR tests though?

 

[cagedanimal2010]

same reason, you may not be i.r the whole of the circuit if there is a break, there for leading you to potential danger.

Danny

 

[Deleted member 26818]

Lack of continuity would affect other tests, such as IR.