S

smartspark

Where are the max Zs for TT circuits to be found in the regs, I have 32.9 ohms at the stake, which is great, the readings for Zs on the circuits are between 18.81 and 19.69 ohms, does this look correct, dont do much TT work so excuse me for being green :o
 
There's no max Zs listed for a TT. It's recommended you get it below 200ohms although and RCD a still operate above this up to 1666ohms.

If you've 32.9 ohms at stake you haven't done bad.
 
Last edited:
I did find table 41.5 in the red bible, wasn't sure. It does state 1667ohms but only up to 32A, Ive installed a 45A for the range cooker newly installed, guess that must be OK at those results, awesomely quick reply, thanks.
 
asa long as all circuits are RCD protected. no problem.
 
it's because , due to the high Ze, you can't achieve disconnection times with the overcurrent device, and so you rely on the RCD for fault protection.
 
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

Daily, weekly or monthly email

Thread Information

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

Thread Tags

Advert

Thread statistics

Created
smartspark,
Last reply from
Engineer54,
Replies
7
Views
1,029

Advert

Back
Top