Discuss 18TH Regs Chapter 46 - 46.2 in the Electrical Wiring, Theories and Regulations 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

John-

-
Reaction score
48
Hi

This reg states that TNCS or TNS systems do not need the neutral isolated. Is that at sauce or generally?
Why?
What about TT systems?

Thanks

John
 
In a TN system the neutral is considered to be at or relatively close to 0 volts /earth potential as the earthing conductor returns to the source and is connected at the star point where the neutral is also connected making them the same potential.
A TT system has no earthing conductor returning to the source , the earth fault loop impedance is via the general mass of earth through an earth electrode (s) so a difference in potential can exist.
In a 3 phase and neutral TT installation the installation must isolate all live conductors by a 4 pole isolator at the origin
In a TN 3 phase and neutral installation only the line conductors require isolating at the origin
In a domestic installation regardless of earthing arrangement type, a double pole switch must isolate the installation at the origin.
Part 7 electrical installations may also require the neutral is isolated in certain different earthing arrangements
 
Last edited:
Thanks Ian. The reference to domestic you make is that 462.1.201 (p121)? Is that because of the assumption that non-domestics are three phase or more to do with functional switching or none of the above? Thanks.
 
Thanks Ian. The reference to domestic you make is that 462.1.201 (p121)? Is that because of the assumption that non-domestics are three phase or more to do with functional switching or none of the above? Thanks.
Because domestic installations are used by ordinary persons who are prone to careless actions with regards to electricity
 

Reply to 18TH Regs Chapter 46 - 46.2 in the Electrical Wiring, Theories and Regulations 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
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