MCB Breaking Capacity

[spark 68]

Just looked at some Wylex and square D SP ones (all I have to hand), both only show the Icn value, Wylex 6kA on the side, and the square D on the front 6000 in the box, both 6kA types.

Other MCB's may be different.

 

[telectrix]

they probably also say " made in china"

 

[JUD]

Have a look at Table 7.2.7(i) on page 71 of the green On-site Guide (if you have one). All will be revealed...:shades_smile:

If you don't have the green one yet it's page 57 in the red one

 

[Duncan Bennett]

Some excellent information, Guys. Why weren't you all about when I was sitting my apprenticeship in the 70's!! And don't give me that " .... oh the internet wasn't invented then." If you have all that combined knowledge you might have invented something as simple as the internet before now!!

I was actually looking to fill in the boxes on the generic IET Schedule of Test Results. I do have the Green OSG, but I find navigating it a bit tricky yet - my synapses don't work as quickly as you young uns

Thanks again and ... I'll be back.

 

[telectrix]

did we have electrickery in the 70's or were we still on gas lamps.?

 

[Duncan Bennett]

Not quite but almost! I remember the boss would drop everything to strip out the pipework for old gas mantles when we on rewires - it was £1 per 1LB back then and I started my time a £9.14 a week!

 

[Jay Sparks]

Not quite but almost! I remember the boss would drop everything to strip out the pipework for old gas mantles when we on rewires - it was £1 per 1LB back then and I started my time a £9.14 a week!

Wow, I think Noah got more than that for sailing the arc......




Just to add... The Ics is also on the Hager mcbs.

Just found one...



Jay

 

[Risteard]

this is not marked on the device, and you will normally have to refer to the manufacturers data for this.

Usually both Icn and Ics are stated on the device, with Icn in amperes and Ics in kiloamperes.

 

[spark 68]

Sorry mate,

I think you will find it is the In that is marked on the device, or the nominal tripping current ie. for example Type no. B, In 6A, and as we have already said the Icn eg. 6000 or 6kA, and as Jay said, some, not all also have the Ics noted on too.

I think you are mixing up the In with Icn, we were discussing the breaking capacity, not the nominal trip rating.

 

[Risteard]

No - Icn is in amperes (e.g. 6000 or 10000) and Ics in kiloamperes (e.g. 3).

I'm not referring to the rating of the circuit breaker (e.g. 32A).

 

[spark 68]

sorry to disagree, re-read the earlier posts, the 6000 in A, is the Icn, which is 6kA

 

[Des 56]

Not quite but almost! I remember the boss would drop everything to strip out the pipework for old gas mantles when we on rewires - it was £1 per 1LB back then and I started my time a £9.14 a week!

Gents,please forgive the intrusion, can I high-jack this thread a little, just to pose a question to any "golden oldies"

What was your first wages?
I got the princely sum of 3 Pounds 1 shilling,which was handed straight over to mam,she then gave me pocket money out of it.

What was your's ?

 

[telectrix]

you must be older than me then , des, i started on £6 odd at the start of my app.

 

[spark 68]

Risteard,
I think we are talking at cross purposes here, the 6000 or 10000 in the little box is marked in Amps, this is the Icn value usually given as kA, eg 6 or 10 kA, the In is also marked in amps eg. 6 or 32 or whatever.

Some, but not all mcb's also have the Ics value marked on them, the Wylex and Square D single phase ones I have here do not have the Ics value marked, but some of Jay's did.

 

[Des 56]

you must be older than me then , des, i started on £6 odd at the start of my app.

Maybe not tel.I started a plastering app for the first 3 months at age 15,my electrical app was £6 ish with the NCB when I turned 16 so much the same as you