On Thu, 23 Oct 2014 14:28:52 +0100, John Rumm wrote:

On 23/10/2014 12:02, Uncle Peter wrote:
On Thu, 23 Oct 2014 10:55:11 +0100, Dave Plowman (News)
wrote:

In article ,
Uncle Peter wrote:
It might trip if overloaded, which is its
purpose. As a fuse will blow.

But they're too sensitive to transients like bulk capacitors.

Then use the correct one.

They're against the regs.

Why do you keep making these daft claims?

There are three types of Miniature Circuit Breaker, denoted as type B,
C, & D.

A circuit designer is free to choose whichever is appropriate for the
circuit.

A "normal" type B breaker will have a nominal trip current, which is
provided by a thermal mechanism (i.e. like a fuse), and a fast acting
magnetic trip mechanism for clearing "fault" currents (i.e. overloads
many times the nominal rating).

All the different types of a given nominal rating will have the same
thermal response characteristic.

Since inrush currents can "look" like momentary faults even a type B
breaker will tolerate short duration loads of 3 to 5 x its nominal
rating before tripping.

A type C will allow 5 - 10x, and a type D up to 10 - 20x its nominal
rating.

http://wiki.diyfaq.org.uk/index.php?...ypes_B.2CC.2CD

The designer should choose the appropriate one for the circuit. So if
you are switching a large bank of strip lights with magnetic ballasts,
then a Type C will be more sensible than a B. For circuit with a 5kW
blower motor, a type D may be more appropriate.

Well we had B for a room of 20 computers. I was told it had to be B. I eventually persuaded him to fit C, which improved things a bit. Then later on a different electrician ignored the rules and fitted a D.

--
How do you play Iraqi bingo?
B-52...F-16...B-2