Type mcb/rcd/rcbo

[sparky1502]

Can anyone please tell me the difference between type b and type c mcbs/rcd/rcbo"s

 

[DurhamSparky]

the curve characteristics!!

plus ZS readings for Type C are lower due to same reason!!

http://www.voltimum.co.uk/news/1826/cm/selecting-the-right-mcb-----its-as-easy-as-bcd-.html

 

[sparky1502]

curve???the shape ?

 

[DurhamSparky]

Type B mainly for domestic stuff..!
Type C mainly found on industrial/comercial sites i.e large lighting circuits with contactors and also with small machinery i.e motors , pumps

 

[sparky1502]

thanks durham i had a small idea but dont remember it being mentioned in college thanks for the explanation

 

[High Tower]

Type D for industrial with high start up current, I.E banks of welders and large motors

 

[DurhamSparky]

to be honest not much diff!! you can fit Type C in a house if you wanted to as its more "universal" never fitted a type D one yet mind! thats proper industrial machinery!

 

[nickblake]

As the guys have said , C and D types are normally found in commercial and industrial applications , where a piece of equipment requires a higher rating to cover inrush and start up currents , IE moters pumps large heating systems , welders Industrial machinary etc

 

[ukpablo]

type c has a higher threshold before it trips, so a high inductive load such as a motor may trip for example a 20A type b mcb because the start current is say (22A for example on start and then 16A normal running current) , however a type C will allow the current to exceed the 20A breaker for a short amount of time during the initial start of the motor, so as not to allow the breaker to trip when settling back to 16A running current!

this is just an example

look at log log chatrs in BRB for type B and type C breakers and u will see the difference

page 249 and 250
look at overcurrent characteristics for both fuse types in table.

ie 20A for both and u will see the difference!