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Why is there 6 and 10kA for same circuit breaker?(sales)

The famous question that causes much confusion: The BS 60898 and IEC 60947 for Euro and African countries.

The same breaker but two different kA ratings …come on!

Why, why, why – Is it because the British is a big contributor to IEC that’s why IEC bent the rules to accommodate them?

But having said so, the poor Brits must be the hell in when they get a CB and on it is printed 6kA and according to his tables it is supposed to be 4.5kA.

Simplified: If you use this breaker in a household application – or more technically correct- Operated by untrained persons then 60 898 applies.

If used in the industrial complex expected to be operated by trained persons then it falls under 60 947-2. 

What is the logic behind it all: Using the circuit breaker in applications where the kA rating is much lower will ensure trouble free continuous operation. Makes sense now does’nt it?

If your daughter operates it you want to ensure the component is as safe as possible. Makes perfect sense now.

But then I can’t help but to ask the question: So what does this mean about the circuit breaker…We don’t trust it at the higher kA…mmm. As long as it explodes in an electricians hands its fine? Really?

Huhuh, there is something wrong with the logic here! Is this why electricians are paid the good money…danger pay?

No no, no…This is why they get paid the good money:- Switching a circuit breaker on load.

This is why electricians get paid the good money:

OSHA 1910.334 –  from http://www.ieee.org/index.html

Use of Equipment (b) Electric power and lighting circuits.

(2) Reclosing circuits after protective device operation. After a circuit is de-energized by a circuit protective device, the circuit protective device, the circuit may not be manually reenergized until it has been determined that the equipment and circuit can be safely energized. The repetitive manual reclosing of circuit breakers or  reenergizing circuits through replaced fuses is prohibited.

Note: When it can be determined from the design of the circuit and the overcurrent devices involved that the automatic operation of a device was caused by an overload rather than a fault condition, no examination of the circuit or connected equipment is needed before the circuit is reenergized.

But what if one does not know to comply with the above prohibition?   We call such a person an untrained person resulting in this bottom-line?

If a CB complies with 60 947 -2 and also classed and used as 60 898 ensures the breaker is used in an underrated environment ensuring an even safer working of the CB.  And that is the real reason!

So next time you hear an agitated electrician or customer complaining about making things difficult…just smile.