MCB type

[David E]

Can anyone help with the difference in MCB types (BC&D) I remember one trips less easially eg bulb blowing on a lighting circuit, but can't remember which one.

David

 

[andy]

Can anyone help with the difference in MCB types (BC&D) I remember one trips less easially eg bulb blowing on a lighting circuit, but can't remember which one.

David

try searchin. there are plenty thread about this

B is the standard type. use C for lights if the trippin wil cause a problem when lights blow. D are used for stuff needing high power levels to startup

 

[kai]

A method to remember:-
B is Basic type MCB for household use.
C is "Commercial" for commercial use Or Similar etc.
D is Dangerous type - leave well alone in domestic homes.

 

[ban-all-sheds]

http://www.diynot.com/forums/viewtopic.php?p=76467#76467

 

[Big_Spark]

Andrew, to blindly say that Type C should be used for lighting circuits is dangerous.

Type C breakers have no place in a domestic environment, if a light blowing causes the MCB to operate, then this is usually indicative of some other problem, usually cheap and nasty lamps or faulty transformers on LV lighting.

Unless you have a home filled with fluorescent lights, you should have no requirement to take into account the high induced loads these can produce, which is why banks of lights in Offices and similar environments are protected by Type C breakers.

What you have proposed is similar to increasing the fuse size in the old days...stupid and dangerous.

No-one should install a type C breaker in a domestic premises as there should be no need for them. Correctly installed fittings, wiring and intelligent choice of lamps will normally eradicate all nuisance tripping caused by lamp failure.

 

[Big_Spark]

A method to remember:-
B is Basic type MCB for household use.
C is "Commercial" for commercial use Or Similar etc.
D is Dangerous type - leave well alone in domestic homes.

Hogwash Kai, I suggest you look it up properly.

 

[andy]

Andrew, to blindly say that Type C should be used for lighting circuits is dangerous.

Type C breakers have no place in a domestic environment, if a light blowing causes the MCB to operate, then this is usually indicative of some other problem, usually cheap and nasty lamps or faulty transformers on LV lighting.

Unless you have a home filled with fluorescent lights, you should have no requirement to take into account the high induced loads these can produce, which is why banks of lights in Offices and similar environments are protected by Type C breakers.

What you have proposed is similar to increasing the fuse size in the old days...stupid and dangerous.

No-one should install a type C breaker in a domestic premises as there should be no need for them. Correctly installed fittings, wiring and intelligent choice of lamps will normally eradicate all nuisance tripping caused by lamp failure.

providing the earth loop is low enough, C6 can be used for lighting circuits

 

[Lectrician]

I like a good......talk.

Max EFL is quite often hard to meet with D type, and can be with C type. But saying that, it could be with a B aswell. You need to calculate and install correctly, and test to insure compliance.

D types are used predominantly for huge transformers, found mainly on large construction sites, X ray machines, welders, forklift chargers etc.

C types are mainly used for motors and lighter transformers/inductors(as found in discharge lighting)

B types are the norm for all other things.

It amazes me how many sparks fit C type breakers as a matter of course with 3 phase DB's. Just because you are using a TP board in an industrial environement doesnt mean all breakers need to be a C type.[/code]

 

[Big_Spark]

providing the earth loop is low enough, C6 can be used for lighting circuits

Andrew, perhaps you should have made that comment in your original post, but I still disagree.

A properly designed circuit should not suffer from nuisance tripping, however should the client choose to use cheap and nasty lamps, that should not be an excuse to fit C type breakers, but rather an opportunity to educate the client and inform them of the merits of buying quality lamps which are more cost effective in the long term and avoid the nuisance trip issue.

 

[andy]

providing the earth loop is low enough, C6 can be used for lighting circuits

Andrew, perhaps you should have made that comment in your original post, but I still disagree.

A properly designed circuit should not suffer from nuisance tripping, however should the client choose to use cheap and nasty lamps, that should not be an excuse to fit C type breakers, but rather an opportunity to educate the client and inform them of the merits of buying quality lamps which are more cost effective in the long term and avoid the nuisance trip issue.

i usually go with C for lighting circuits to avoid the trippin when a bulb blows. altho i always check the earth loop before i use C instead of B

 

[Big_Spark]

Personally that is bad practice, you are using a breaker to overcome poor performance in other aspects of the installation, that could, in theory at least, lead to other issues should different types of fault occur.

 

[Damocles]

Cobblers FWL, installing a circuit which will trip unnecessarily causing nuisance and possibly even danger to the occupants is not good design. Whether you like it or not, you must be well aware that any circuit you install WILL be fitted with bulbs which WILL trip the breakers.

Are you the sort of person who just walks straight across the road without looking because all drivers are supposed to avoid pedestrians?

It might not be possible to use either a B10 or C6 in place of a B6, but probably it is. If in doubt, check. That is not at all the same as using the wrong fusewire. It is the same as using the right fusewire.

 

[ban-all-sheds]

I use good quality, Ballotini fused lamps.

When they fail the breaker trips every time. And remember, not all lamp types are available with fuses anyway.

To say that you should not use a Type C seems to fly completely in the face of the requirement to design circuits properly, which includes ensuring that the specification of the breaker is correct for the load on the circuit.

 

[securespark]

Oooh, Goody, Ban!!

Can I get out my Osram hat again???!!!

 

[plugwash]

i think some modern mcbs are incredibbly fast so much so that even the fastest fuse designs would find it almost impossible to keep up

from http://www.electrium.co.uk/download_file.asp?Type=C&Company=8&Id=1 (warning LARGE pdf)

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