Zs on tt

[Sparky Ninja]

If people are having trouble understanding this magic '1667 ohms' number.. it is obtained from:

50V / 30mA = 50 / 0.03 = 1666.6666666666666666666666667, rounded up to 1667 ohms.

 

[jaresquire]

I think you missed a few 6's there, Widdler

 

[sparx24]

was about to say as widdler max. touch voltage 50 so 50/0.03mA = 1666 recuring rounded to 1667, but OSG says anything over 200 ohms should be considered unreliable due to soil drying out ect.
TT probs with B.Gas 'engineers' having plug in Go/noGo testers for supply to boilers having fail setting of a couple of ohms, trouble is they are always taught on TNS systems and don't understand TT.

 

[IQ Electrical]

was about to say as widdler max. touch voltage 50 so 50/0.03mA = 1666 recuring rounded to 1667, but OSG says anything over 200 ohms should be considered unreliable due to soil drying out ect.
TT probs with B.Gas 'engineers' having plug in Go/noGo testers for supply to boilers having fail setting of a couple of ohms, trouble is they are always taught on TNS systems and don't understand TT.

No, the On-Site Guide is referring to the RA value (the Ze if you like) NOT Zs values!