Discuss Funny old game,why oh why in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

cliffed

-
Arms
Reaction score
644
Real busy/hard day,2nd fix remote office in garden.
Finished,now the testing.
It’s way out in the countryside,measured Zs @ DB in house, 0.02 ohms,PSC 23 ka, seems unusual.
DB in office a 6.0mm 3c swa,Zs 1.05 ohms.
That’s really not possible,the cables about 35 m in length,crap end to the day,going to try another tester,& re test.
 
could the Zs be affected by the MCB feeding the 6.0mm? you could calculate Zs from R1+R2. ( + Ze ).
 
Agree,all dead tests are really low,the Zs are ridiculously high,@ the new DB the Zs is 1.05 ohms.
Worked out the swa should be around 0.20 ohms @ DB in office
It’s gotta be the tester.
 
Hi - I've not seen that in domestics myself, so I think you're right to question the result. It sounds like you've a low Ze and the meter isn't handling it well. Perhaps try cable in series with your tester to get the value up and see if it makes more sense then.
Is there a transformer out front perhaps?
 
try getting a loop reading from the outgoing side of the RCD. (L-E). if it is > than your previously measured Ze, then that could be the reason your Zs is so high.
 
a RCD can sometimes affect the Zs readings by a significant amount. i once had one that added 349 ohms to the value.
Had that bowel emptying moment a few times when testing Zs with RCD in line.

It's like, can't be, can't be, that's just not possible. Then face palm and realise there's an RCD duh.
 
try getting a loop reading from the outgoing side of the RCD. (L-E). if it is > than your previously measured Ze, then that could be the reason your Zs is so high.

Likewise, I'll test before and after and if the RCD is the cause use a calculated Zs.
 
Some RCDs did give high values.

I would check another existing circuit for comparison reasons

And do a Zs on the outgoing terminals of the RCD
 
Last edited by a moderator:

Reply to Funny old game,why oh why in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock