Product Manual

382357 V2.2 09/10 8

Measurement Principles

Typical multi-grounded distribution system

If the parallel ground resistances,

, R

,etc, up to R

are combined

as R

, then only R

and R

are

left in the circuit

If a constant voltage is applied to the circuit, the following equation applies:

eqg

where: ni

,...2,1,

∑

If R

and R

, R

…R

, are approximately the same, and n is large (200, for example),

then R

will be much less then R

and may possibly approach zero.

Example:

If R

and R

, R

…R

are all 10Ω respectively and n = 200, then R

by calculation

equals:

Ω=

= 05.0

...

geqg

RRR

→=+=+=

05.1005.010