diy:electrical_faults
Table of Contents
troubleshooting electrical faults
see also:
Introduction
- this is a guide to help you ascertain what is causing your RCD or circuit breaker to trip
- for automotive electrical issues see:
- any electrical repairs on circuits with voltages higher than 30V should be done by a qualified electrician!
No power
- troubleshooting:
- is it just one device?
- check the power cords are plugged in correctly and the correct power switch is turned on
- is there a local circuit breaker for that power switch - if so check it
- consider removing the cord for 20secs and then re-inserting to “reboot” the device
- does the device have a fuse - this may be blown
- try a different power point in case it is an issue with that power point or that circuit
- otherwise it may be a device failure
- is it just one power board?
- you may have over-loaded it and triggered the circuit breaker or fuse on the board
- remove devices, reset the circuit breaker and try again avoiding excessive wattage or current load rated for that board (usually 2400W in Australia)
- is it just one circuit in the house?
- most likely cause is either the circuit breaker or RCD have tripped - check the circuit board and then see below for troubleshooting
- is it the whole house?
- check you neighbours - it may be a local blackout
- if your house is the only one - check you circuit board main power switch
- if the circuit board seems fine, perhaps your power company has stopped supply due to unpaid bills or a power company issue
Circuit breaker tripped or fuse blown
- this is due to an excessively high current occurring and is usually caused by either:
- short circuit
- this is generally caused by faulty wiring or faulty electrical device
- excessive power load current draw
- most household power circuits in Australia are rated to 10A 240V = 2400W (some circuits are rated to 15A such as kitchen ovens)
- if you exceed 2400W on one circuit then the fuse will blow or circuit breaker will trip
- lightning strike
- this would be a rare cause and likely to trigger all circuit breakers or fuses
- troubleshooting:
- check devices on that circuit to ensure they are not combining to give excessive wattage
- turn all devices off on that circuit, turn circuit breaker back on
- if it trips immediately then there is a short circuit in the wiring from switch board to the power points
- if it doesn't trip, sequentially turn on all power points on that circuit
- if one trips it then that is the fault
- if it hasn't tripped then try sequentially running each device on the circuit
RCD earth leakage safety device triggering
- this is due to detection of current leaking to ground from either the active or neutral wires
- NB. circuit breakers, fuses and power switches are generally breaking the active line of an AC circuit - thus if the RCD is still tripping despite all these being OFF, then the issue is likely to be a faulty RCD device or less commonly, a persistent neutral line to ground leak (these do not generally create enough current to trip an RCD but could do so)
- this is usually caused by either:
- if occurs after new RCDs installed:
- new RCD is more sensitive than older ones and thus may trigger when the old one didnt from low earth leakages of 30mA
- clamp-meter the earth or neutral to measure leakage milliamps with the appliance running before trip, to see how close to 30 mA it is
- MEN/earth bars are not configured correctly for your board layout
- neutral being shared with other RCDs - this is particularly likely if BOTH RCDs have tripped at the same time (both do not need to trip for this fault to be present)
- a faulty appliance
- damaged insulation on wires
- exposed neutral wire contacting ground (could be an active wire but without enough current to trigger the circuit breaker or fuse)
- moisture near electrical wiring
- faulty RCD device
- troubleshooting
- you may know what caused it by it happening as soon as an event happened such as turning a device on or house maintenance where wiring may have been affected
- turn off all circuit breakers that are controlled by that RCD
- if RCD still won't reset to ON, then it may be either:
- a neutral wire leaking current to ground
- a faulty RCD device
- if RCD resets to ON, then sequentially turn back on the circuit breakers
- if the RCD is triggered when turning on a circuit breaker then the fault is in that circuit
- turn all power switches off on that circuit
- if the RCD still trips when turning that circuit breaker on, it suggests a neutral wire leaking current to ground
- if RCD resets stays ON when the circuit breaker is turned on then sequentially turn back on the power switches on that circuit
- if the RCD trips when turning a power switch on then the device connected to that switch is faulty
- if RCD resets stays ON then you may need to run a device on that circuit to see if the device is causing the issue
diy/electrical_faults.txt · Last modified: 2026/02/17 23:01 by gary1