12
Fault Finding

Preliminary Electrical Systems

Check

A. EARTH CONTINUITY CHECK - Appliance must
be electrically disconnected - meter set on W
(Ohms) x 1 scale and adjust zero if necessary.
a) Test leads from any appliance earth point to earth
pin on plug. Resistance should be less than
0.1 W (Ohm), check all earth wires for continuity
and all contacts are clean and tight.
B. INSULATION CHECK - Appliance electrically
disconnected, all switches ON.
a) meter set on W (Ohms) x 1 scale.
Test leads from L to N in appliance terminal
block. If meter reads «0» then there is a short
circuit.
b) meter set on W (Ohm) x 100 scale.
Repeat test with leads from L to E. If meter reads
less than ¥ (infinity) there is a fault.
NOTE - Should it be found that the fuse has failed
but no fault is indicated - a detailed continuity check
(i.e. by disconnecting and checking each
component) is required to trace the faulty
component.
It is possible that a fault could occur as a result of
local burning/arcing but no fault could be found under
test. However a detailed visual inspection should
reveal evidence of burning around the fault.
START
Isolate appliance
and carry out:
A: Earth Continuity
check.
Has inlet fuse blown?
Carry out:
C: Polarity check.
Electricity supply
should now be
satisfactory.
Carry out:
D: Resistance to
Earth check.
Inlet wiring
faulty.
Rectify any
fault.
Isolate appliance and
carry out:
B: Insulation check.
Rectify any fault
including replacing
fuses as necessary.
SOCKET
(face view)
PLUG (with cover
removed)
Earth Wire
Green/Yellow
Neutral Wire
Blue
Brown Blue Green
Yellow
Green
Yellow
Brown
Blue

( )

FUSE

( )

E

NL

NO YES
NO YES
A. IGNITOR SWITCH
B. IGNITOR UNIT
B
L
N
0
1
2
3
4
5
6
220/240
A
Wiring Diagram