diffrent types

[james king]

hi all,

can any one tell me or has a link to were i can find the diffrences between type B,C and D MCBs. why and when will u use them ?

 

[telectrix]

type B are general use. C and D are used when equipment has a high surge current on start up e.g.motors. characteristics of the types are in brb.

 

[johnboy6083]

type b tripping cuirrenty is 3-5 x In, general use
type C is 5-10 x In, flourescent lights, small motors and small transformers.
Type D is 10-50 x In, larger motors, large lighting installs. larger transformers

 

[IQ Electrical]

hi all,

can any one tell me or has a link to were i can find the diffrences between type B,C and D MCBs. why and when will u use them ?

Have a read of this link, some good stuff there!

Selecting the right MCB - its as easy as BCD! - Voltimum UK - Electrical Installation Products and Contracting

 

[james king]

thats good thank mate.. now i am confused about why the mcb are rated to trip at 3 to 5 times its rating why would this be?? surly there would be no point insatlling diffrent rarted mcb??

so why not install 10A B MCB for all domestic ccts????

 

[telectrix]

think of the c and d types as anti surge fuses i.e. slow blow. they will withstand large overcurrent for short periods.

 

[BathSparks]

In old consumer units CBs were referred to as types 1,2,3 etc. How does this relate to the type letters we have now?

 

[malcolmsanford]

These are the old BS 3871 and you can see quite a good guide to these in the OSG pg 58 Table 7.5.

 

[BathSparks]

Thanks, will check that out.