Problem with PSSC on three phase supply

[sparksburnout]

I have a domestic premises (it was once a shop) that has a three phase supply, although only one is being used now. I am using a di-log 9083P tester, and when doing a Ze test am getting 23KA as the reading for PSC, with 0.01 ohms as the loop resistance. I am getting a Ze of 0.35 ohms and a PFC of 565A. The values for PSC and L-N loop impedance seem unbelievably low to me? I am not sure where the local transformer is but it is not next door, I think it is about 400yds away. System is TNS. I have looked at the thread in the I&T forum, and used the method of inserting an impedance in the earth lead of the tester, but I am still getting the same readings, which as far as I can see you would, as it is for low Ze not low PSC. I have used the tester on about 3 other installations, and it is giving expected results. Could it be possible that these values are correct? In which case the main switch and breakers are well underrated!!

 

[GLENNSPARK]

just check your readings again will you on Zpn....caus 23KA ffs....

 

[sparksburnout]

just check your readings again will you on Zpn....caus 23KA ffs....

I know! I just tried it again over the road at my mates house, and it's giving very similar readings now - the previous ones I mentioned were Zs. This meter is quite new, I suppose it could be faulty, or is it that these meters are just not capable of working properly at low Ze's? It is still giving a P-N loop res of 0.01 ohm that can't be right even if the transformer was next door???

 

[tom79bmth]

I know! I just tried it again over the road at my mates house, and it's giving very similar readings now - the previous ones I mentioned were Zs. This meter is quite new, I suppose it could be faulty, or is it that these meters are just not capable of working properly at low Ze's? It is still giving a P-N loop res of 0.01 ohm that can't be right even if the transformer was next door???

Hi if I leave my megger in the van over night when it's cold I get strange pfc and loop readings I leave it inside in the warm for a hour works fine it has been calibrated a few times now with out any problems,had me scratching my head at first

 

[pepparz]

I know! I just tried it again over the road at my mates house, and it's giving very similar readings now - the previous ones I mentioned were Zs. This meter is quite new, I suppose it could be faulty, or is it that these meters are just not capable of working properly at low Ze's? It is still giving a P-N loop res of 0.01 ohm that can't be right even if the transformer was next door???

it can be 0.01, thats what it is at the factory i work at

 

[Bobster]

It can be lower than that still, although you start needing specialised gear to test that low.

 

[Engineer54]

it can be 0.01, thats what it is at the factory i work at

Only close to the Factories distribution Transformer(s)...

 

[Engineer54]

It can be lower than that still, although you start needing specialised gear to test that low.

Not outside of a large commercial/industrial environment...

 

[Bobster]

Not outside of a large commercial/industrial environment...

I was just making the point.

 

[Engineer54]

I was just making the point.

So was i. ...lol!!

 

[pepparz]

Only close to the Factories distribution Transformer(s)...[/QUOTE
where else would u test Ze

 

[pepparz]

eng u dont need to write what everone already knows

 

[Engineer54]

Errr, Who know's if you even had your own Distribution TX??

 

[pepparz]

by the low reading durrr

 

[Geordie Spark]

eng u dont need to write what everone already knows

I didn't know.

But I know my way around a Regin Regu 35 Manometer AND I have two Neon Screwdrivers!!

 

[pepparz]

Errr, Who know's if you even had your own Distribution TX??

actually we dont, but quite close to a transformer.

 

[Geordie Spark]

actually we dont, but quite close to a transformer.

We have a big grey thing at the top of our street surrounded by a green steel fence.

I'm thinking about sending a picture of it to Tony - he likes things like that.

 

[pepparz]

i've hundreds of photos like that from around the country, when we go to caravan sites i stop and take a pic whenever i see one. our lass says im a sad b*****d.

 

[Deleted member 72666]

i've hundreds of photos like that from around the country, when we go to caravan sites i stop and take a pic whenever i see one. our lass says im a sad b*****d.

She may have a point!

 

[pepparz]

its a hobby, people like what they like.

 

[Geordie Spark]

its a hobby, people like what they like.

I agree.

I like Industrial Archaeology (think Fred Dibnah) and all that sort of stuff, Rockabilly, Rock n Roll, Southern Boogie, Fleetwood Mac, Dire Straits, photography, Toyota MR2s, Duck Dysentery on TV and a very funny Pikey woman.

 

[pepparz]

i also collect spades and have a decent colletion, my best been a 1930's cast steel digging spade double braced on ash shaft with a box "D" handle.

- - - Updated - - -

love watching old fred dibnah episodes on sky.

 

[Geordie Spark]

i also collect spades and have a decent colletion, my best been a 1930's cast steel digging spade double braced on ash shaft with a box "D" handle.

- - - Updated - - -

love watching old fred dibnah episodes on sky.

Yes .... he was a grand bloke.

I must say I admire blokes who can call a spade a spade.

Tidyboiler tells me her Dad ( a tough little Pikey bloke) always called a spade a spade and often to his face.

I have a collection of woodworking tools that were made and used by my Grandfather in a very impressive tool chest that he made himself.

I think to a collector they will be worth some money.

 

[pepparz]

it was fred dibnah who got me into traction engine rallies (not personally mind) cant wait for pickering's rally in august.

 

[Geordie Spark]

it was fred dibnah who got me into traction engine rallies (not personally mind) cant wait for pickering's rally in august.

I used to get around a lot but haven't been able to for the past couple of years cos I've not been well.

I always wanted a good camera outfit and after about 30 years finally got it - all packed in a big fluck off rucksack that I can't carry .......

 

[pepparz]

well i do hope your health starts to improve:20:

 

[Geordie Spark]

well i do hope your health starts to improve:20:

Thank you.

I appreciate that, the past months since October have not been much fun, but could be worse. I think I'm picking up a bit now since Friday when Tidyboiler almost literally dragged the GP by his balls from his full surgery direct to my bedside!

I had his full attention from then on.

 

[pepparz]

well done tidyboiler!

 

[telectrix]

Only close to the Factories distribution Transformer(s)...

or on an eng54 installed rod. lol. :75:

 

[guest119]

We have a big grey thing at the top of our street surrounded by a green steel fence.

.

Thats your local shop Geordie :ciappa:

Boydy

 

[telectrix]

I used to get around a lot but haven't been able to for the past couple of years cos I've not been well.

I always wanted a good camera outfit and after about 30 years finally got it - all packed in a big fluck off rucksack that I can't carry .......

go on then. keeping us in suspenders, what camera?

 

[Geordie Spark]

go on then. keeping us in suspenders, what camera?

Canon 30D

Old(ish) but does the job - a bit like you Tel.

Bag full of assorted lenses -Canon & Sigma, Sigma flashgun, Manfroto tripod and a monopod (one legged tripod) bits & bobs and I can't lift the bloody thing.

 

[tidyboiler]

Canon 30D

Old(ish) but does the job - a bit like you Tel.

Bag full of assorted lenses -Canon & Sigma, Sigma flashgun, Manfroto tripod and a monopod (one legged tripod) bits & bobs and I can't lift the bloody thing.

A bit like my make-up bag.

 

[trev]

Meanwhile back at the OP.
Might sound silly but how are you off for charge in the battery pack? Many testers start to give really daft readings if they're low.
I also think you may need to check your reading as it does not work out to 23Ka

 

[Geordie Spark]

A bit like my make-up bag.

I don't understand why you drag all that clarty stuff around with ye - ye divvent need it - yer bonny enough withoot it!!

 

[trev]

Furthermore, a Ze of 0.1 ohms at the distance you quote from the transformer is unlikely in my experience. I once did a rewire less than 50 metres from one and the reading I got was 0.47, considering how streets are wired this isn't beyond the realms of possibility but I checked it with different testers both very recently calibrated and they agreed.
I'd definitely be checking those batteries mate.

 

[Engineer54]

or on an eng54 installed rod. lol. :75:

As good as any of my earth rods may be, i somehow doubt they would have any influence on L-L or L-N fault currents!! lol!!

 

[telectrix]

Canon 30D

Old(ish) but does the job - a bit like you Tel.

Bag full of assorted lenses -Canon & Sigma, Sigma flashgun, Manfroto tripod and a monopod (one legged tripod) bits & bobs and I can't lift the bloody thing.

nice. i have the 10D. even older.does everything i need, though. only gripe i have is the size of the LCD screen 1.8".