Fault Finding
Preliminary Electrical Systems Check
PLUG (with cover removed) | SOCKET |
| (face view) |
Brown Blue Green Yellow
Blue
BrownGreen Yellow
START
Isolate appliance and carry out:
A:Earth Continuity check.
Earth Wire | ( ) |
Green/Yellow | |
Neutral Wire | FUSE |
| |
Blue |
|
N
E(
)
L
NO | YES | Carry out: | Carry out: |
| Electricity supply | ||||
D: Resistance to |
|
| should now be | ||||||
|
|
| C: Polarity check. |
|
|
| |||
|
|
| Earth check. |
| satisfactory. | ||||
|
|
|
|
|
|
| |||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Has inlet fuse blown?
NO | YES |
Inlet wiring faulty. Rectify any fault.
Isolate appliance and carry out:
B:Insulation check. Rectify any fault including replacing fuses as necessary.
A. EARTH CONTINUITY CHECK -
Appliance must be electrically disconnected - meter set on Ω (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 Ω (Ohm), check all earth wires for continuity and all contacts clean and tight.
B. INSULATION CHECK - Appliance electrically disconnected, all switches ON.
a)meter set on Ω (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 Ω (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.
18
