Measured Zs up the swanny?

[Amp David]

Did a Zs on a lighting circuit today and the value was less than my calculated value.

Haven't got my note to hand so can't give the exact figures. Thought it could be supplementry bonding somewhere, but there isn't any.

Can anyone shine a light on the matter

 

[Guest123]

What about the main equipotential bonding then???

 

[telectrix]

could be supp. bonding hidden from view somewhere, boxed in? as long as it's a good reading, and not too far from calc. job's a good 'un

 

[Mr Mark Sparks]

need more circuit info and readings really but sup bonding/parallel paths would explain it
metal conduit systems and bathrooms with the 4mm at every point

 

[brucelee]

yes lenny spot on will have a lower value beacause of the parlell earth paths from the main protective bonding conductors
When you calculate from Ze + (R1+R2) this doesnt so will give a higher value than the measured value

 

[Amp David]

I know main bonding could lower the Zs. From memory the diiference was around 0.6 ohm

 

[Amp David]

yes lenny spot on will have a lower value beacause of the parlell earth paths from the main protective bonding conductors
When you calculate from Ze + (R1+R2) this doesnt so will give a higher value than the measured value

Any paralell path will affect all circuits you test, but its only on the lighting circuit that figure are vastly different??

 

[Jimmy Boy]

Higher than normal resistance in the CB ?

 

[Jimmy Boy]

Higher than normal resistance in the CB ?

I'm a dum --- that would make it higher...