Type B or Type C

[pieman2008i]

Hi there,

just a quick question...

I have seen a good deal in my local wholesaler on consumer units & associated paraphernalia, I was wondering what type of RCBO is better in a domestic situation? B or C???

Before you beat me to death with a hardback copy of part P I am having a friend of mine (NIC installer) do the work!

Thanks in advance!

 

[tonylec]

can't really see a need for type C in the home, may be an advantage if you have a home workshop with some machines that could run on a type C (to alow for inrush currents) apart from that type B should be fine and is the norm, cheaper generally too

 

[electronicsuk]

Type B is generally used in domestic installations. Type C must be used carefully, and if connected to your existing cabling, it's possible that you may not be able to comply with required disconnection times.

 

[pieman2008i]

Wow! Many thanks for super quick replys

Type B it is then...

Jus wondering what C are for then? things like tool sharpners, lathes(spl), & bandsaws? would have thought a 3 phase supply would be more suited to that? But what do I Know?! lol

 

[kai]

Jus wondering what C are for then? things like tool sharpners, lathes(spl), & bandsaws? would have thought a 3 phase supply would be more suited to that? But what do I Know?! lol

Type B is for Resistive type loads, and general domestic loads, except for perhaps lighting circuits, which might need a C6 or C10 type breaker.

Type C is for Inductive type loads, whose starting or inrush currents might trip out a B type on start-up.

Things like Cookers, Immersion heaters, Showers and electric fires will ALWAYS require a B type for optimum earth loop resistance safety.

 

[electronicsuk]

Jus wondering what C are for then? things like tool sharpners, lathes(spl), & bandsaws? would have thought a 3 phase supply would be more suited to that? But what do I Know?! lol

MCBs are available in 1, 2, 3 and even 4 pole varieties, although the number of supply phases and MCB poles has little to do with the trip curve of the MCB. Equipment with high startup currents on initial switch on, including items such as bandsaws, lathes (and many things that contain large motors) may cause a type B to trip during normal use. When necessary, the use of a C or D type can eliminate this, but the circuit must be designed accordingly.

 

[1john]

type c breakers can be useful on lighting circuits imo.

 

[pieman2008i]

type c breakers can be useful on lighting circuits imo.

can you elaborate on that for me please?

Is it or is it not a good idea to mix breaker type within the same consumer unit? (assuming there are things with motors & or starters in a domestic situation)?


Just curious

 

[PrenticeBoyofDerry]

Type C devices have a better ability to handle surge currents without tripping.
Inrush currents associated with fluorescent and other forms of discharge lighting, can cause a Type B to trip, when no fault apparent, which can be nuisance.

 

[1john]

or occasionally when a lamp fails

 

[spark1]

6A. B -Type Breakers installed on lighting circuits have the effect of unwanted tripping when a lamp [ bulb ] Expires-- goes--pops...blows !

6A. C -type Breakers with their different Tripping Characteristics will overcome this problem....circuit design permitting of course ,as has already been stated

 

[1john]

yes, worth stating that the maximum permitted Zs for a type C breaker is lower than a type B so it's something that cannot just be replaced without consideration.

 

[ban-all-sheds]

Before you beat me to death with a hardback copy of part P I am having a friend of mine (NIC installer) do the work!

Therefore you should not be doing the design work - only he is allowed to do that.

 

[pieman2008i]

My friend is doing the work, but is currently away in Switzerland, I just saw a good offer & was curious what the difference between type B & C breakers are...

 

[bongos]

My friend is doing the work, but is currently away in Switzerland, I just saw a good offer & was curious what the difference between type B & C breakers are...

That old chestnut...

Go for B-type.