Earth ElEctrodE / Earth loop rEsistancE

continuity of pE conductors / conductivE parts

nominal differntial current i∆n (ma) 10 30 100 300 500 1000

r earth (Ω) max. (uc<50 v) 5000 1666 500 166 100 50

r earth (Ω) max. (uc<25 v) 2500 833 250 83 50 25

1

2

insulation rEsistancE linE / nEutral to pE3

limits: Where no rcd, select limit from the fusE characteristics, test by Z loop. Where rcd:

GuidE throuGh vErification on loW-voltaGE ElEctrical installations : iEc 60364-6

protEction by automatic disconnEction of thE supply4

rEports and cErtificatEs on loW-voltaGE ElEctrical installations: iEc 603645

tn system - two clamps - clamps arround main N/PE cable

tt system - two wire - test from the socket N to PE

it system - three wire - test leads to rods in triangle

lightning system & Earth loops - test each loop

iEc 60364-6 61.3.6.2., b.3., equipment: iEc 61557-5 limits:2 Ω above ground10 Ω whole system 10 Ω underground per leg or 8% of Specific Earth Resistance

L1

L2L3

PETN

N

L1

L2L3

PE

N

TT

L1

L2L3

PE

N

TT

IEC 60364-6 61.3.2., equipment: IEC 61557- 4Parameters:±200 mA both directions, all exposed conductive parts to MPE and in between where distance < 2.5 m.

Limits:

or 2 Ω max. (where RCD built-in)

R ≤Uc

Ipfc

50V

200A0,25 Ω≤ ≤ (where Fuse C20A built-in)

iEc 60364-6 61.3.3., equipment: iEc 61557-2

parameters: 500 v dc 250 v dc for PELV/SELV limits on circuits: r min > 1 mΩ r min > 0.5 mΩ for PELV/SELV floor and wall resistance/impedance r > 50 kΩ (insulated) semiconductive coatings 1 mΩ < r > 1 GΩ Protection against static electricity (EN 61340-5-1)

leakage current - alternative method for testing and tracing insulation problems without disconnection parameters: trms Low range measurement limits: 1 ma/kW or 3.5 ma max. per app. 5 ma max. where heating app. 1/3 x idn where RCD protected circuits. Leakage < 100 ma for fire protection.

fuse: Z loop l-pE / Z line l-l, l-n iEc 60364-6 61.3.6.3., 61.3.11., equipment: iEc 61557- 3parameters / limits are characteristics of particular built-in Fuse, designed for trip-out time of:0.1 s (Explosive), 0.2s (3Phase Circuits), 0.4 s (1Phase systems) or 5 s (fixed connections). Measured values of Impedances from the end of the circuit must be lower than Zs from the table.

In (A)

tip b tip c tip GIa = 5x In (A)

Zs= (Ω) (0,2 s)

Ia= 10x In(A)

Zs= (Ω) (0,2 s)

In(A)

Zs= (Ω) (0,4 s)

2 10 22 20 11 16 13,7

4 20 11 40 5,5 32 6,8

6 30 7,3 60 3,65 47 4,6

10 50 4,4 100 2,2 82 2,6

16 80 2,8 160 1,4 110 2,0

20 100 2,2 200 1,1 147 1,4

rcd: trip out time, trip out current iEc 60364-6 61.3.6.1., 61.3.7., equipment: iEc 61557- 6

More Parameters/Limits could be found in Metrel Handbooks and inside Eurotest/Smartec testers.

RCDrcd trip out at differential id (ms)

1/2 x I∆N 1 x I∆N 2 x I∆N 5 x I∆N

General No trip t∆ < 300 t∆ < 150 t∆ < 40

Selective No trip 130 x t ∆ < 500 60 x t∆ < 200 50 x t∆ < 150

RCD slope range (from-to)

0,5 ÷ 1.0 x l∆N AC

A 0,35 ÷ 1.4 x l∆N

B 0,5 ÷ 2.0 x l∆N

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