Zs on TT

[i=p/u]

What is the point in carrying out zs on TT system other than verifying a loop.
We got an Ra of 14.8 but when all bonding is in place it comes down to 1.9 ohms for most circuits zs results. I just don't see the point if rcd protected .

 

[Lucien Nunes]

I was going to write a silly answer but I gave up because I couldn't make it as silly as the question. Can you rephrase?

I read it as: Why test Zs on a system where the Ze is much higher than the Zdb? Or maybe: 'Why test Zs when the results are going to be high but not too high.' Either way it's pretty wacky.

 

[Marvo]

This one is a serious contender for 'thread of the week' award, I've had tears rolling down my face whilst reading it.

I assume Mr I=PU is asking why is the Zs relevant if you know the Ra is good enough to meet the required earth impedance on its own without the assistance of parallel paths.

Okay, I'm going to let the English who apparently 'are slow' and allegedly 'on the ale' sort this one out

 

[JD6400]

This one is a serious contender for 'thread of the week' award, I've had tears rolling down my face whilst reading it.

I assume Mr I=PU is asking why is the Zs relevant if you know the Ra is good enough to meet the required earth impedance on its own without the assistance of parallel paths.

Okay, I'm going to let the English who apparently 'are slow' and allegedly 'on the ale' sort this one out

Don't forget that we are all apparently Gay as well ! :shocked3:

Edit; According to another thread at the moment that is !

 

[Marvo]

Lol, sorry, I forgot about the gay thing. You have to admit though this thread is damn funny....

 

[JD6400]

I am meant to be " up stairs " but I am weighing it up at the moment , as I may miss the show tonight !

 

[Des 56]

Lol, sorry, I forgot about the gay thing. You have to admit though this thread is damn funny....

That last thread confirmed only the English as gay,we can rest easy:hurray:

 

[Engineer54]

I'm just lost for words!!

An Ra of 14 ohms and Zs of 1.9 ohms, .....Yep why bother testing??

 

[GLENNSPARK]

looks like i`v missed a few good opportunities this evening to have a go..

got called out to a faultfind which turned out to be several neutral-earth faults...

and yep....the RCD was tripping...

it aint now though.....

 

[i=p/u]

No glen not have a good go, no no no , support what I am saying.

if you have ze of 14 ohms what is the point of doing zs test , as you know your readings are to high for protective device already.


Brains just ain't your friend last two days guys , AAA?

 

[i=p/u]

I'm just lost for words!!

An Ra of 14 ohms and Zs of 1.9 ohms, .....Yep why bother testing??

You are relying on rcd on a TT for fault protection or not.... I think I've worded this all wrong. Help me out.

 

[Hawkmoon]

What is the point in carrying out zs on TT system other than verifying a loop.
We got an Ra of 14.8 but when all bonding is in place it comes down to 1.9 ohms for most circuits zs results. I just don't see the point if rcd protected .

Assuming this is not a wind up...

Forget the fact this is TT and rethink what a Zs test is for

 

[Hawkmoon]

I'm just lost for words!!

An Ra of 14 ohms and Zs of 1.9 ohms, .....Yep why bother testing??

On reading this - coffee exited my nose

 

[i=p/u]

On a 6A lighting circuit max zs is 6 odd ohms to disconnect a fault within specified time . On this TT system with 100mA rcd, our Ze is14 ohms soothe breaker won't trip within time, so relying in rcd.. Oh my god

 

[Hawkmoon]

On a 6A lighting circuit max zs is 6 odd ohms to disconnect a fault within specified time . On this TT system with 100mA rcd, our Ze is14 ohms soothe breaker won't trip within time, so relying in rcd.. Oh my god

I hope the 'Oh my god' signifies the end of your blonde moment!

 

[i=p/u]

I should of started work 30 mins ago... I. Beg belief