A Grade Electricians
FAQs
How do I repair a blown fuse?
What is the difference between a circuitbreaker and a Safety Switch (RCD Residual Current Device)
How do I know if safety switches (RCDs) are fitted to my home
How do I know if my home has been rewired?
How do I know if my wiring is safe?
How do I repair a blown fuse?
WARNING! Always switch off the main switch(es) to the premises before touching any part of a switchboard. If you are not confident you can undertake this task safety, call a licenced electrician. It is illegal for an unlicenced person to interfer with wiring in an installation.
As a basic rule of thumb, if you need a tool to make repairs, YOU NEED TO BE LICENCED. Fuse wedges may be removed for repair by a competent person, but under no circumstances should the switchboard panel or cover be removed.
Before repairing a fuse, consider what may have caused it to blow in the first place. Was the circuit overloaded (too many high current appliances connected), is an appliance faulty, is there a wiring fault, or has the fuse wire become weak with age and finally failed?
In the pictures above, you will see two parts which couple together. The fuse wedge is the front part of a fuse assembly and is removable, the base is fixed to the switchboard panel. The base has brass connections for the wiring and is live while the main switch is turned on. This is why you always should switch off the main switch(es) before attempting to repair a blown fuse.
An inspection of the fuse wire (or lack of) will give an indication to the cause of the fuse blowing. If the fuse wire has a slight gap in the middle, it indicates a minor overload or aging. Some times it is not obvious the fuse has blown and you may need to pull gently on the fuse wire to see if it has broken in the middle of the fuse wedge.
An overloaded circuit caused by too many appliances operating simultaneously, will blow a larger section of the fuse wire.
A major wiring fault or appliance fault will cause a high current surge and may completely blow all the fuse wire, leaving a blackened fuse wedge. It is very important that the cause of this fault is removed before the fuse is repaired and reinserted. Failure to remove the cause of the fault can damage wiring and lead to a potential house fire.
IMPORTANT! When replacing the fuse wire, it is vital that the correct size fuse wire is used. The fuse wire is in the circuit to protect the wiring and prevent a fire occurring. Using a larger size fuse wire can allow more current to flow through the circuit than the wiring is capable of safely carrying.
Common fuse sizes are;
| Amps | Use |
| 10 | Lights |
| 16 | Power |
| 20 | Air Conditioner, Hotwater |
| 32 | Stove |
How do I know if Safety switches have been installed in my home?
With so much confusion surrounding the difference between safety switches and circuit breakers, it is often common for people to believe they have safety switches when they do not.
The difference between them is explained on ther safety switch page. Click here to learn more. Use your browser back arrow to return back to this page.
Determining if Safety switches are installed, it is necessary to inspect the Electrical Switchboard. A Safety switch looks like a circuit breaker but has a push button on the front of the device for testing purposes. There may be a combination of circuit breakers and one (or more) Safety switch. If you cannot see a device on your switchboard that looks like the Safety switch shown, it is still possible (but unlikely) that you have safety switch protection. Some installations have powerpoint safety switches where the safety switch is inbuilt into the powerpoint. These powerpoints have a test and reset button visible on the front or top of the powerpoint.
If you are still unsure, give us a call and we will advise you further.
Has my home been rewired?
It always amazes me how many people will invest hundreds of thousands of dollars purchasing a home and not think to get the wiring checked before their purchase. There is plenty of unlicenced wiring work installed, as well as damaged or dangerous wiring. Home insurance can be a waste of time if insurance companies find illegal wiring was the cause of damage.
It is common to meet clients who believe their home has been rewired, but on inspection, discover their home still contains perished old wiring.
This can sometimes be due to a misunderstanding. An Electrician may tell their client that they rewired a part of the installation and the client has thought all the old wiring was replaced. The Electrician may have only replaced a section of the wiring.
Inspecting:- An inspection in the roofspace and under the floor (in accessable) is necessary to determine if the installation's wiring is in good condition. Even new wiring can become unsafe due to damage by rodents, pets, etc.
We have seen extremely dangerous situations caused by rats, mice and possums. Often wiring insulation is completely chewed away leaving bare copper conductors. Once damaged, moisture from roden excrement or rain can cause a shortcircuit of wiring and a potential fire.
It is common to find old wiring deteriating faster behind lightfittings, where the outer insulation has been removed and the wiring is close to the roof where the temperature is greater.
If you are inspecting the wiring yourself, look for conduit wiring (wires in metal pipes), cap and casing (wiring in wooden channels), or rubber insulated and sheathed cables (black sheathed cable). Inspecting wiring yourself can only be done visually. It is not safe to inspect wiring behind switches, powerpoints or switchboards.
Disclaimer: the disclaimer class can be used for notes, terms and other little legal type things.