Still unsure

[Billythekid]

This has been troubling me for some time now. . . . .

At my previous company i was asked to go and Verify the test results/Install for a Voltage Optimiser that we'd fitted. I traced the supply cables from LV Panel to source, these ran through the building, down into ducts, and continued into an Intake panel (Located in next room to DNO's TX). I found several items that needed addressing, these were:
no removable link at MET for either the Main Earth, or generator set.
Main earth not connected (Intake Panel)
High Zs readings (caused by above)
PSCC exceeding Limit of protective devices within LV Panel

I wrote my report/submitted it, to which i received a response along the lines of (I'll summarise) . . .
Where in the installation is it that should be under 0.0424 ohms as this seems incredibly low. If we connect the Earthing conductor this will make the PSCC issue worse.

This confused me, how can connecting an earthing conductor increase PSCC? PEFC i get, but PSCC?


The supply cables were 240mm2 4cores in parallel, with a seperate 185mm2 Earth. Neutral link was in Intake Panel (DNO's side). The 'engineer' said "because this is a TN-C-S system, this would result in a higher PSCC". I've thought about this fairly often and can not answer how?

Thanks peeps

Billy

 

[Billythekid]

No takers?

 

[Billythekid]

I assume my mind is right then, There is no possible way?

At first I thought maybe the engineer thought that the link was at the main LV. So I let him know that it was at the intake panel, but he stood by his earlier statement. Then explained to him that I was wrong with a maximum Zs of 0.0424, to be fair the actual was 0.0432 (hang him, lynch him). But again he said that was too low, perhaps he knew something that the fuse manufacturers didn't, or he was out of his depth?

Who am I to question an engineer with more letters after his name than my whole address? I'm no academic, but am fairly confident with my training/basic understanding of electrical principals. Unless there is a vast difference between what I was taught, and what they teach engineers, I'm at a loss.

For those of you thinking "is this lunatic writing to himself?" . . . Yes, and I also talk to myself .

Oh, and and give myself a bloody good talking to

Regards

Billy

 

[ifindoubtdont]

Talking to yourself is good, arguing with yourself and loosing the argument is bad. I told myself many a time, but I never listen.

 

[ian.settle1]

Talking to yourself is good, arguing with yourself and loosing the argument is bad. I told myself many a time, but I never listen.

Ha Ha reminds me of when I was working on a high speed ferry which was laid up over the winter.

On nights there was three onboard me, bosun and the captain (who was Italian) later on that night we where watching the TV all of a sudden I and the bosun heard someone shouting in Italian we turned to find the captain shounting at himself only to answer himself back in English apologising to himself.

Mentioned it to the captain who was coming to days he said he was mad as a hatter after spending years on supertankers