Ze test results

[NozSpark]

Which bit sidey??

Because around here (for domestic at least) they can't even tell you the supply type, never mind Ze, without attending!

 

[batty]

I just typed a huge reply and the site lost it sorry Batty I can't do this again.Suffice to say this is not the situation.

Hate it when that happens you loose the will to live.

 

[Sidewinder]

Noz,

At a certain PFC/PSCC/PEFC no matter what you call it the DNO cap the value by design, thus the Ze becomes irrelevant!

This in the critical value in reality.

 

[NozSpark]

I see where you're coming from now

 

[steptoe]

TNCS, do they still guarantee it will never be more than 16kA ?

thereby allowing a BS1361 to be compliant.

I take it this is the general idea that sidewinder is hinting towards.

 

[Sidewinder]

This will depend on the DNO Specs, down by me at the mo I can't remember, though the figure that sticks in my mind coz I came close is the 3ph is 25kA!

They confirmed this even though the sub was on site & less than 10m away and the Zs was less than 0.01 ohms!

I could not measure the Ze as I could not switch off the 160A ACB at the incomer!!!

This was part of the DNO switch gear which was part of the consumers switchgear too!!!

I fitted a 25kA MCCB as the 35 was out of stock and would have been a few days and was a LOT more expensive!!!

Customer wanted the supply NOW as usual, so I was lucky!

 

[m4tty]

just hope you dont need a 40c in a TNS install. :slap

Can anyone explain this for me please lol.

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And what's an acb please? Is it one of them breakers which are oil filled? Prob not but just a guess

 

[NozSpark]

The DNO stated Ze for a TNS installation is 0.8ohms

The max Zs for a C40 is 0.575ohms

 

[Sidewinder]

Steps may have been referring to a 40 core cable?

Matty, and ACB is an air circuit breaker, it utilises an air blast to extinguish the plasma arc generated when it interrupts fault current, they can be rated at very high fault current interrupt values.

Google air circuit breaker and check out the manufacturers info rather than relying on wikipedia though that may not be a bad place to start, though it is hackable and not always correct.