Low Ze, high(ish) R1+R2, Got a plan but just had an idea

[Risteard]

come the 18th it isn't allowed at all

Not strictly true. But if you do that then you become the manufacturer of the assembly and are responsible for type-testing it etc.

I would suggest that this is already the case and has always been - the new Regulation simply highlights this explicitly.

 

[Risteard]

One comment: Annex Zb.

 

[Baddegg]

As a newbie I’ve just spent the whole day doubting myself, I couldn’t for the life of me see the connection between KA and the zs readings...thank f&#k for that!

It doesn’t as you know. The op has had us up a garden path talking about Zs when he should have been asking about PFC.

 

[Wilko]

As a newbie I’ve just spent the whole day doubting myself, I couldn’t for the life of me see the connection between KA and the zs readings...thank f&#k for that!

Hi - 10kA rated devices are more common in industrial applications, as are C type MCBs. So it's easier to find 10kA C type perhaps (?).

 

[Nigel]

Hi - 10kA rated devices are more common in industrial applications, as are C type MCBs. So it's easier to find 10kA C type perhaps (?).

Hi - 10kA rated devices are more common in industrial applications, as are C type MCBs. So it's easier to find 10kA C type perhaps (?).

Most industrial installations should not be using BS 60898 MCBs.

 

[westward10]

Not even on small power and lighting.

 

[Nigel]

Not even on small power and lighting.

Not if the environment the DB is installed is not fit. 60898s should only be used in domestic style settings. Good temperature regulation etc.

You could use then in offices but in unheated warehouses they should not be used.

 

[Toneyz]

The circuit protective device should be chosen with many factors to be considered. Don't quite agree with the statement that BS 69898 can't be used in industrial installations.

 

[Nigel]

The circuit protective device should be chosen with many factors to be considered. Don't quite agree with the statement that BS 69898 can't be used in industrial installations.

On what basis do you not agree?

 

[westward10]

The circuit protective device should be chosen with many factors to be considered. Don't quite agree with the statement that BS 69898 can't be used in industrial installations.

I agree these are still working fine

 

[westward10]

Joking aside I see hundreds in the factories I work in.

 

[Nigel]

Joking aside I see hundreds in the factories I work in.

So do I. Not right though.

 

[Toneyz]

On what basis do you not agree?

mainly for the reasons you backtracked from your original statement between posts 45 and 47 you have obviously come across situations where they should have not been used what were they?

 

[Baddegg]

Hi - 10kA rated devices are more common in industrial applications, as are C type MCBs. So it's easier to find 10kA C type perhaps (?).

Hi wilko
Thanks for that,just confused the hell out of me as I couldn’t see where upping the KA rating of the breaker was an answer to the high zs readings, as a newbie I use this forum as a training tool, try and work out my solution before reading through and seeing what the experienced hands come up with, I understood that the low Ze was causing his issue with KA of the mcb but I couldn’t see how changing to a c type helped him with the high Zs (I thought c type had a lower maximum?) am only domestic so obviously don’t have much contact with c’s and I certainly don’t have the experience or confidence to call out anyone yet! Ha ha
Just out of interest to the op I use CEF own brand boards (MCG) and breakers there rcbos type b are all 10ka and they also do them in mini rcbo format so plenty of room

 

[Nigel]

mainly for the reasons you backtracked from your original statement between posts 45 and 47 you have obviously come across situations where they should have not been used what were they?

Not sure I have backtracked on anything. I will start a new thread.

 

[Strima]

Hi wilko
Thanks for that,just confused the hell out of me as I couldn’t see where upping the KA rating of the breaker was an answer to the high zs readings, as a newbie I use this forum as a training tool, try and work out my solution before reading through and seeing what the experienced hands come up with, I understood that the low Ze was causing his issue with KA of the mcb but I couldn’t see how changing to a c type helped him with the high Zs (I thought c type had a lower maximum?) am only domestic so obviously don’t have much contact with c’s and I certainly don’t have the experience or confidence to call out anyone yet! Ha ha
Just out of interest to the op I use CEF own brand boards (MCG) and breakers there rcbos type b are all 10ka and they also do them in mini rcbo format so plenty of room

Do you understand the different curves of MCBs and how they relate to their intended use?

 

[Baddegg]

Hi strima, understand that they trip at different amounts of load current, type c/d is used to cater for higher inrush currents without tripping on start up of moters etc in industry, I’ll be honest I can’t remember why they would have lower max zs values

 

[Strima]

Hi strima, understand that they trip at different amounts of load current, type c/d is used to cater for higher inrush currents without tripping on start up of moters etc in industry, I’ll be honest I can’t remember why they would have lower max zs values

Does 5x, 10x & 20x ring any bells?

 

[Baddegg]

Yep,over full load currents trip times?

 

[Baddegg]

Yep, percentage over full load current they trip at?

Does 5x, 10x & 20x ring any bells?

Hi strima
think the pennies dropped now,thanks for taking the time much appreciated

 

[Baddegg]

Hi wilko
Thanks for that,just confused the hell out of me as I couldn’t see where upping the KA rating of the breaker was an answer to the high zs readings, as a newbie I use this forum as a training tool, try and work out my solution before reading through and seeing what the experienced hands come up with, I understood that the low Ze was causing his issue with KA of the mcb but I couldn’t see how changing to a c type helped him with the high Zs (I thought c type had a lower maximum?) am only domestic so obviously don’t have much contact with c’s and I certainly don’t have the experience or confidence to call out anyone yet! Ha ha
Just out of interest to the op I use CEF own brand boards (MCG) and breakers there rcbos type b are all 10ka and they also do them in mini rcbo format so plenty of room

Edit. Not ALL they come in both 6&10 ka

 

[delano]

And when did ka come into it and what does that have to do with this job?

A bit of blind leading the blind going on here.

10k, 6k? Has he checked tested the Ipf? It's not that complicated.