Hi guys, doing bit of revision here. What is the correct answer to give under exam conditions to this question? State why Ze-Zr cannot be used to accurately determine the value of R1 + R2? Could it be something to do with number of connections within the circuit under test, possibly a loose connection etc which would then give a higher Zs reading? I'm sure there must be a more obvious answer. Thanks
 
Hi guys, doing bit of revision here. What is the correct answer to give under exam conditions to this question? State why Ze-Zr cannot be used to accurately determine the value of R1 + R2? Could it be something to do with number of connections within the circuit under test, possibly a loose connection etc which would then give a higher Zs reading? I'm sure there must be a more obvious answer. Thanks


What's Zr when it's a home?
 
Driverman

parallel paths can make an enormous difference to the final Zs. The difference of an order if the Ze is appalling (which it often is, TT wise).

so for example, you may get a Zs of 6.4 Ohms for a circuit with a Ze of 122 Ohms and an R1+R2 of 0.67 Ohms.

how could Zs - Ze ever be a useful measurement, except in how useless it might be....do you see from the example above?

the bonds to the water pipe and gas pipe in the example above massively reduce the Zs.


In fact, some properties that are TT can happen to be connected via a water main to another nearby property that is TN.... Thus producing even more incredulous results (like a Ze at the earth rod of say, 34 Ohms but the socket circuit reads 0.34 Ohms for its Zs).

s.
 
Best EV Chargers by Electrical2Go! The official electric vehicle charger supplier.

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

Advert

YOUR Unread Posts

Daily, weekly or monthly email

Thread starter

Joined
Location
England
If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
United Kingdom
What type of forum member are you?
Retired Electrician

Thread Information

Title
Zs - Ze
Prefix
N/A
Forum
Electrical Wiring, Theories and Regulations
Start date
Last reply date
Replies
7

Thread Tags

Tags Tags
None

Advert

Thread statistics

Created
driverman,
Last reply from
SPARTYKUS,
Replies
7
Views
1,668

Advert

Back
Top