TESTING ZS

[shed69]

If you really want to know the R1+R2 ...

DON'T use the method shown in the GN3 or OSG...

Just take BOTH Line & CPC out of the board and connect them together with a lever Wago connector,...

Then go to your light and read the R1+R2 at the fitting!

:C

Excellent advice....... My preferred way every time......

 

[SPECIAL LOCATION]

Hi All , That was my point from the begining, i always dis-connect the CPC from the earth bar at the consumer unit and connect to the phase conductor,its the only way to be sure of continuity and ignoring parallel earth paths, Thats why i disagree with the procedure in guidance note 3 for continuity of a lighting circuit. (linking earth bar to phase conductor). Also please confirm question i asked before. By connecting a 4mm earth cable to the earth terminal of a bathroom light for supplementary bonding, wouldnt it be possilble for a fault current that may develope at the light fitting to elect to travel down the supplementary earth , thereby passing possibly 100-150 amps of fault current down the pipework and back to the main earth terminal

If you read Guidance Note 3 in context you will find the instructions are correct..

Remember these are the instructions for INITIAL inspection & testing NOT periodic..

and as I said on Post #12...

Go back and read the previous page.. :|

Specifically this bit....



Prior to fixing accessories and bonding straps is the clue..

Fault current.......

As the max Zs for a type B 6A 60898 is 7.67ohms,

The fault current to achieve 0.4second disconnection is {230/7.67} 30A

If a 10A type B circuit it is 4.6ohms,

And this fault current to achieve 0.4second disconnection is {230/4.6} 50A

Any parallel path providing an overall lower resistance down two or more shared routes..

would.....

a) Divide the actual fault current down each leg proportional to their respective resistances

and....

B) Most probably reduce the disconnection time